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Journal Cover Journal of Applied Ichthyology
   Journal TOC RSS feeds Export to Zotero [8 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0175-8659 - ISSN (Online) 1439-0426
     Published by John Wiley and Sons Homepage  [1603 journals]   [SJR: 0.427]   [H-I: 33]
  • Molecular characterization of the cDNAs of two zona pellucida genes in the
           Chinese sturgeon, Acipenser sinensis Gray, 1835
    • Authors: H.‐M. Yue; H. Cao, X.‐H. Chen, H. Ye, C.‐J. Li, H. Du
      Pages: n/a - n/a
      Abstract: The Chinese sturgeon, Acipenser sinensis, is a large‐sized panadromous cartilagous fish and requires more than ten years to reach sexual maturity. An understanding of the reproductive organs and fertilization process is a precondition for controlled reproduction of this endangered species. The developing oocyte is surrounded by an extracellular matrix composed of the zona pellucide (ZP) protein in several isoforms, all of which play important roles in fertilization and embryo protection. The present study reports the identification of two ZP genes, AsZPAX and AsZPB, in this fish. The full‐length cDNAs of AsZPAX and AsZPB were 2950 base pairs (bp) and 1832 bp, predicting proteins of 946 and 592 amino acid residues, respectively. Both proteins have a conserved ZP domain. In a gene tree, AsZPAX and AsZPB were respectively clustered with their counterparts in other vertebrates. Tissue distribution analysis demonstrated that the AsZPAX RNA was transcribed in both the ovary and the liver, while AsZPB was transcribed exclusively in the ovary. RNA in situ hybridization revealed apparent RNA expression of both AsZPAX and AsZPB in growing oocytes of the 4‐year‐old ovary.
      PubDate: 2014-09-19T02:02:28.604193-05:
      DOI: 10.1111/jai.12586
       
  • Effect of dietary conjugated linoleic acid supplementation on the growth,
           lipid metabolism, and plasma lipid levels of juvenile Amur sturgeon
           (Acipenser schrenckii Brandt, 1869)
    • Authors: C.‐G. Yang; H. Wen, M. Jiang, W. Liu, F. Wu, J. Tian, Q.‐W. Wei
      Pages: n/a - n/a
      Abstract: The study investigated the effects of dietary conjugated linoleic acid (CLA) on the growth, lipid metabolism, and plasma lipid levels of juvenile Amur sturgeon Acipenser schrenckii. In the study design, fish were initially fed a carbohydrate‐enriched diet to obtain ‘high‐lipid or obese’ fish plus a control (NC). In the second step, the high‐lipid fish were divided into four groups and fed increasing levels of CLA at 0% (MC0), 0.5% (MC0.5), 1.0% (MC1.0), and 2.0% (MC2.0) in their diet. The initial control fish (NC) and the other four groups (MC0–2.0) were set up as an experimental series. Each group had three replicate tanks and 15 fish in each tank. After 6 weeks of feeding, specific growth rates and the condition factor were significantly reduced in the 1.0 and 2.0% CLA‐supplemented groups compared with the initial control (NC) and MC0 group. Body lipid content in the 2.0% CLA group was also significantly lower than in the control and other experimental groups. Compared with the MC0 group, lipid liver content in the 2.0% CLA‐supplemented group decreased significantly. Total serum cholesterol was significantly lower in the 1.0% and 2.0% CLA‐supplemented groups. Serum high‐density lipoprotein cholesterol was significantly lower in the 2.0% CLA group than in the MC0 group. There were no differences in survival rate, feed conversion efficiency, body moisture, body protein content, hepatosomatic index, serum triglyceride, or low‐density lipoprotein cholesterol among all experimental groups. The results suggest that adding CLA to fish diets is advisable as it can reduce growth and lipid accumulation in both the body and liver, and affect the regulation of blood lipid levels in juvenile Amur sturgeon.
      PubDate: 2014-09-19T02:01:03.237121-05:
      DOI: 10.1111/jai.12601
       
  • Effects of dietary lipid sources on growth performance, carcass
           composition, and blood parameters of juvenile Chinese sturgeon (Acipenser
           sinensis Gray, 1835)
    • Authors: F. Wu; W. Liu, Q.‐W. Wei, H. Wen, M. Jiang, C.‐G. Yang, J. Tian
      Pages: n/a - n/a
      Abstract: The study investigated the effects of different dietary lipid sources on the growth performance, carcass composition, and blood parameters of juvenile Chinese sturgeon, Acipenser sinensis. Seven iso‐nitrogenous and iso‐energetic diets containing different lipid sources were prepared, i.e. fish oil (FO), soybean oil (SO), groundnut oil (GO), rapeseed oil (RO), corn oil (CO), pork lard (PL), or fish oil: pork lard (1 : 1, FPL). Each experimental diet was fed to triplicate treatments of eight Chinese sturgeon juveniles with initial weights of approximately 47.5 g in indoor tanks for 10 weeks. The FO, SO, and CO treatments had significantly higher weight gain and specific growth rates than the other treatments. Muscle lipid content of the FO treatment was significantly higher than that of the PL treatment, but significantly lower than that of the SO treatment (P 
      PubDate: 2014-09-19T02:00:50.343947-05:
      DOI: 10.1111/jai.12593
       
  • Effects of dietary dextrin on growth, feed utilization and body
           composition of juvenile Chinese sturgeon, Acipenser sinensis Gray, 1835
    • Authors: W. Liu; H. Wen, Q. W. Wei, J. Zhou, M. Jiang, F. Wu, Y. Shi, C. G. Yang, J. Tian
      Pages: n/a - n/a
      PubDate: 2014-09-19T01:58:57.15314-05:0
      DOI: 10.1111/jai.12592
       
  • A short history of sturgeon caviar production in Turkey
    • Authors: Devrim Memis
      Pages: n/a - n/a
      Abstract: Compared to other countries, caviar production in Turkey has a short history, which began principally in the early 1950s, peaked during the 1960s, and began to decline towards the end of the 1970s. Sturgeon fishery was practiced in the estuaries of the rivers Kızılırmak, Yeşilırmak, Sakarya and Çoruh. Thus, processed caviar originated from the districts of Carsamba, Bafra (Samsun City) and Karasu (Sakarya City) and appeared mainly in the markets of Istanbul. Techniques used to capture mature fish were nets set at sea and with hooks (‘karmak’ in Turkish) at the mouth of a river. Two processing techniques were commonly used: (i) malossol/mongol caviar (lightly/highly salted) and (ii) pressed caviar. Landings were mainly recorded in the Istanbul Kumkapı fish hall, reaching 300 tonnes per year in the late 1960s; however, catches declined drastically in the 1970s to only about 30 tonnes. In 1962, caviar production from Acipenser sturio was between 1200 and 1300 kg in the Yeşilırmak River; 1000 to 1200 kg in the Kızılırmak River; and 50 to 80 kg in the Sakarya River. For A. nudiventris, the respective data were 300–400 kg from Yeşilırmak River; 500–600 kg from Kızılırmak River; and 200–250 kg from Sakarya River. The rapid decline in Black Sea sturgeon stocks led to catch restrictions in Turkish coastal areas beginning in 1971. Following the construction of several hydrodams on the main sturgeon rivers in the 1970s, the few sturgeon spawning grounds that remained were drastically affected. Further deterioration of riverine environments was caused by increased pollution in the 1970s–1990s. Sturgeon catches dropped rapidly to less than 10 tonnes after 1975, whereby the fishery collapsed with only a few fish recorded sporadically after 2000. Over the past five years, aquaculture farms began to rear sturgeons for caviar production, with anticipation of initial marketing in 2014–2015. The forecast for 2020 is on the order of 6–8 tonnes of caviar per year.
      PubDate: 2014-09-19T01:56:01.640561-05:
      DOI: 10.1111/jai.12602
       
  • Validation of a methodology to determine female white sturgeon (Acipenser
           transmontanus Richardson, 1836) habitat use within a riverscape during the
           spawning season
    • Authors: V. L. Paragamian; P. Rust
      Abstract: The objective was to use hydrologic and bathymetric models for the riverscape of the Kootenai River, Idaho, USA and integrate these data with radio telemetry locations of two female white Sturgeon, Acipenser transmontanus Richardson, 1836, during the spawning season. The detailed analysis of habitat features and models provided an enhanced understanding of the habitat preferences of spawning White Sturgeon, which could be used to protect or enhance the habitat. Hydrologic models will also provide a basis to incorporate a larger sample of fish in the future. The White Sturgeon habitats were studied during the 2002 and 2003 spawning seasons. Depth sensitive radio transmitters, geographic positioning systems, single‐beam and multibeam echo sounders and multidimensional surface water modeling were used to identify similarities and dissimilarities in the habitat selection of the two monitored female White Sturgeon. The movements of the two fish were not randomly distributed; both fish spent a significant amount of time swimming near the river bottom and thalweg or resting near the river bottom (within 20% of the lower water column [6–9 m]). Mahalanobis distances quantitatively described the similarities between select habitat features of depth, river velocity and riverbed slope at the studied locations and compared the entire spawning reach. The fish occupied sites previously identified as spawning locations. Both fish selected similar depth, median velocity (0.3 m s−1) and bank preferences, avoiding the shallow water on the inside of meander bends and tending to stay in the deeper water on the outside of meanders. They exhibited a tendency to occupy intermediate velocities in parts of the river where the ratio of the velocity at the fish to the maximum velocity in the channel cross‐section was >0.25 and
      PubDate: 2014-09-16T23:44:21.647658-05:
      DOI: 10.1111/jai.12571
       
  • A review of the structure of sturgeon egg membranes and of the associated
           terminology
    • Authors: M. A. M. Siddique; J. Cosson, M. Psenicka, O. Linhart
      Abstract: Knowledge of the morphological properties, species specific differences, development, and function of the sturgeon egg envelope is of importance for a better understanding of sturgeon reproduction as well as for improvement of the caviar quality. The structure of the egg envelope is similar among the various species, comprising an external envelope (thecal cells, basal lamina, and follicular epithelium), a five‐layered oocyte envelope (adhesive layer, alveolar layer, epilayer, and zona radiata externa and interna) and a layer of oocyte matrix and cortical granules. Egg diameters (1.5–4.9 mm), structure and number of the micropyles (2–52), and the size of the micropylar field distinguish eggs of the various species. The development of the egg envelope within the ovary comprises five stages, with further changes following fertilization with the formation of a fertilization cone. The mechanism of polyspermy block in sturgeon eggs and the role of the micropyle and cortical granules in polyspermy block are also described in this review. This review provides information on the morphology and the developmental stages of the egg envelope that will further the understanding of egg biology of acipenserid species. Standardization of terminology describing the egg envelope would minimize confusion and be helpful for future work on acipenserid eggs.
      PubDate: 2014-09-15T03:04:57.567845-05:
      DOI: 10.1111/jai.12604
       
  • Spatial distribution and habitat choice of adult Chinese sturgeon
           (Acipenser sinensis Gray, 1835) downstream of Gezhouba Dam, Yangtze River,
           China
    • Authors: H. Zhang; C. Y. Wang, D. G. Yang, H. Du, Q. W. Wei, M. Kang
      Abstract: Eight hydroacoustic surveys were conducted between 2007 and 2010 to determine the spatial distribution and habitat choice of adult Chinese sturgeon (Acipenser sinensis) within 85 km immediately downstream of Gezhouba Dam, which is the lower‐most dam blocking upstream sturgeon migration in the Yangtze River. A potential 32 A. sinensis were identified; depth, velocity, etc., characteristics were determined at the sturgeon site with an Acoustic Doppler Current Profiler. Most targets (26 individuals, 81.3%) were in water >12 m deep, and most (29 individuals, 90.6%) targets were near the river bottom. All targets stayed in or were close to the river channel (distance to the thalweg about one tenth of the river width). Fish were primarily distributed among four separate and deep areas. Variations in the water level played no significant role in fish distribution. Large, deep areas attracted the most fish. A preliminary analysis of environmental factors including water depth, flow velocity, Froude number and Reynolds number indicated that the bedform morphology (deep areas) was probably the key factor determining the A. sinensis habitat preference. Future conservation of the sturgeon will be more effective when special attention is given to the four refuges.
      PubDate: 2014-09-15T03:04:43.506718-05:
      DOI: 10.1111/jai.12589
       
  • Improving swimming capacity of juvenile Dabry's sturgeon, (Acipenser
           dabryanus Duméril, 1869) in current‐enriched culture tanks
    • Authors: H. Du; Q.‐W. Wei, X. Xie, L.‐L. Shi, J.‐M. Wu, X.‐M. Qiao, Z. G. Liu
      Abstract: Swimming performance is one of the most important capacities for fish to cope with the harsh conditions in natural ecosystems and thus determines fitness of hatchery‐reared fishes for stocking in the wild. Poor swimming capabilities of hatchery‐reared fishes, including sturgeons, may be linked to the fact that the flow regimes in conventional culturing tanks are very often static and with very low currents, obviously differing from the natural environment. The objectives of the present studies were to: (i) learn about the swimming performance of the Dabry's sturgeon Acipenser dabryanus, one of the critically endangered species restricted to the Yangtze River, China; (ii) ascertain if it is possible to improve the swimming capacity of Dabry's sturgeon (DS) by changing the current flow regime in conventional culturing tanks; (iii) determine the potential effects of such an environmental enrichment practice on the growth and survival of DS. Long‐term culturing protocols with two culturing stages were conducted in a conventional tank with static water (Control, CT) as well as in a current‐enriched tank with a step‐controlled water velocity (CET). Results showed after the first culturing stage, which began with 500 15‐day‐old post‐hatch (dph) DS and ended with 40 dph DS, that the survival rates in CT (91.6%) were higher than that in the CET (84.4%). Total length, fork length and weight of DS in CET (n = 30) were higher than in CT (n = 30), but with no significant differences (P > 0.05). The Ucrit (13.2 ± 2.9 cm s−1, or 2.19 ± 0.48 FL s−1, n = 30) of the 40 dph DS in CET were significantly higher (10.2 ± 3.5 cm s−1, or 1.70 ± 0.59 FL s−1, n = 30) than in CT (P  0.05), whereas the Ucrit (48.5 ± 6.9 cm s−1, or 3.25 ± 0.46 FL s−1, n = 20) of the 80 dph DS in CET were also obviously higher (35.9 ± 8.5 cm s−1, or 2.41 ± 0.58 FL s−1, n = 20) in CT (P 
      PubDate: 2014-09-15T03:03:36.127837-05:
      DOI: 10.1111/jai.12591
       
  • Issue Information
    • PubDate: 2014-09-11T09:41:33.400437-05:
      DOI: 10.1111/jai.12594
       
  • Food preference of paddlefish, Polyodon spathula (Walbaum, 1792), in
           polyculture with bighead carp Aristichthys nobilis (Richardson, 1845) in
           non‐fed ponds
    • Authors: Y. J. Zhu; X. M. Li, D. G. Yang
      Abstract: The food preferences of paddlefish (Polyodon spathula) in polyculture with bighead carp (Aristichthys nobilis) are unknown. Three consecutive analyses of gastrointestinal contents of paddlefish and bighead carp were conducted at 3d, 11d and 19d after introduction into the non‐fed ponds. The objectives of this study were to test for competitive interactions between bighead carp and paddlefish, and to document their preferred prey when the two species have a limited food resource. The results showed that paddlefish and bighead carp are basically competitive in their diets. When they were cultured in one pond at the same density, paddlefish fed more quickly and efficiently, depleting the food resources for bighead carp; however, bighead carp were able to switch and trap small food items with the decrease in available food resources. Moreover, larger zooplankton abundance declined in ponds after fish were introduced.
      PubDate: 2014-09-11T00:59:27.684895-05:
      DOI: 10.1111/jai.12590
       
  • Expression pattern of somatolactin in the Chinese sturgeon, Acipenser
           sinensis Gray, 1835
    • Authors: X.‐Q. Leng; C.‐J. Li, H. Cao
      Abstract: Somatolactin (SL) is a pituitary hormone specific to fish and is reported in a variety of teleost species. Although it appears to be involved in many different physiological processes, its biological functions are poorly understood in Acipenseriformes. In this paper the expression pattern of this protein is characterized in Chinese sturgeon (Acipenser sinensis). Structure analysis showed that AsSL had a 24aa signal peptide and a 208aa mature protein, one N‐glycosylation site at positions 145‐147 and seven Cys residues conserved with other SLs. The antiserum was raised against a 15 aa antigen, derived from the Chinese sturgeon somatolactin (AsSL) amino acid sequence. Western blot analysis showed the pituitary‐specific expression of AsSL. In situ hybridization revealed that the mRNA of AsSL was expressed mainly in pars intermedia (PI), although also slightly in proximal pars distalis (PPD), cells expressing AsSL disperse throughout the pars intermedia. These findings provide useful information for future physiological research in Chinese sturgeon.
      PubDate: 2014-09-11T00:59:13.209264-05:
      DOI: 10.1111/jai.12587
       
  • Morphological and osteological development during early ontogeny of
           Chinese sturgeon (Acipenser sinensis Gray, 1835)
    • Authors: J. Ma; P. Zhuang, B. Kynard, T. Zhang, L. Z. Zhang
      PubDate: 2014-09-11T00:34:25.92974-05:0
      DOI: 10.1111/jai.12585
       
  • Discriminant analysis of blood biochemical parameters at different
           developmental gonad stages and gender identification for controlled
           breeding of Amur sturgeon (Acipenser schrenckii, Brandt, 1869)
    • Authors: L. Z. Zhang; T. Zhang, P. Zhuang, F. Zhao, B. Wang, G. P. Feng, C. Song, Y. Wang, S. J. Xu
      Abstract: Male and female Amur sturgeon (Acipenser schrenckii) at sexual maturity (age 7 years) were identified under controlled breeding conditions, and the plasma biochemical parameters were determined at different developmental stages of the gonads. The results showed that there was significant difference of the plasma calcium (Ca2+) and lactate dehydrogenase (LDH) content between the sexually mature males and females. The LDH content in males was highest, while the Ca2+ concentration was lowest. During different gonad developmental stages (II,III,IV‐A and IV‐B) of the, the content in the ovaries of plasma total protein (TP), globulin (GLB), total bilirubin (TBIL), triglycerides (TRIG), Ca2+ and inorganic phosphorus (P−) initially showed an upward trend, and decreased thereafter. The values of albumin (ALB), albumin/globulin (A/G) and total cholesterol (CHOL) increased gradually from stage of II to IV‐B, and showed significantly higher levels at the stage of IV‐A to IV‐B (P 
      PubDate: 2014-09-11T00:31:21.67945-05:0
      DOI: 10.1111/jai.12584
       
  • Alarm cues in Lake Sturgeon Acipenser fulvescens Rafinesque, 1817:
           potential implications for life‐skills training
    • Authors: V. Wishingrad; J. R. Sloychuk, M. C. O. Ferrari, D. P. Chivers
      Abstract: An experiment was designed to investigate Lake Sturgeon (Acipenser fulvescens) responses to alarm cues and the ontogeny of anti‐predator behaviour in response to alarm cues in larval and juvenile sturgeon. A method for alarm cue preparation in larval sturgeon using full‐body homogenate and juvenile sturgeon using homogenized skin is described. Larval sturgeon in tanks exposed to alarm cues were shown to exhibit a dramatic increase in activity (e.g. an escape response) (t25 = 4.95, P 
      PubDate: 2014-09-10T23:51:50.532533-05:
      DOI: 10.1111/jai.12580
       
  • Dietary lipid to carbohydrate ratio in beluga, Huso huso (Linnaeus, 1758),
           fed two L‐carnitine levels
    • Authors: M. Mohseni; R. O. A. Ozório
      Abstract: A feeding experiment was carried out to determine the optimal dietary lipid: carbohydrate ratio (L:CHO, in %) on growth performance and feed efficiency in beluga, Huso huso (Linnaeus, 1758), juveniles fed two L‐carnitine supplementation levels. Triplicate groups (25 fish/tank) were fed one of eight isoproteic (41% crude protein) and isoenergetic (20 kJ kg−1 diet) diets with increasing L:CHO ratios (12 : 21, 15 : 16, 18 : 5 and 21 : 0) and one of two L‐carnitine supplements (0 or 300 mg kg−1). Fish (initial body weight 480 ± 18.4 g) were housed in 24 fiberglass tanks and fed to apparent satiation for 114 days. Fish fed the 18 : 5: and 21 : 0 had higher weight gain, growth rate, feed conversion ratio and protein efficiency ratio than fish fed the other diets. Growth performance was significantly improved by supplementing 300 mg L‐carnitine to diets. Liver lipid increased with increasing dietary L:CHO ratios and decreased with dietary L‐carnitine level. These results indicated that juvenile beluga did not utilize dietary carbohydrate as efficiently as lipid. Moreover, diets with a dietary lipid:CHO ratio between 18 : 5 and 21 : 0 and supplemented with 300 mg L‐carnitine kg−1 successfully improved growth performance and feed utilization of beluga sturgeon reared in intensive culture conditions.
      PubDate: 2014-09-10T23:11:20.567593-05:
      DOI: 10.1111/jai.12567
       
  • Forensic investigations into a GenBank anomaly: endangered taxa and the
           importance of voucher specimens in molecular studies
    • Authors: C. B. Dillman; P. Zhuang, T. Zhang, L.‐Z. Zhang, N. Mugue, E. J. Hilton
      Abstract: Whole mitochondrial genome (mitogenome) sequences provide a powerful approach for investigating and hypothesizing relationships at a broad range of phylogenetic levels, and these data have been used extensively across the diversity of fishes. Mitogenome sequence studies have typically used an exemplar approach wherein one individual is sampled and sequenced. However, as more laboratories are producing these data, taxon sampling within clades, including within‐species sampling, is naturally increasing. There are currently eleven acipenserids with complete mitogenome sequences available for download and use from GenBank. Exploration of these sequences indicates that the mitogenome for Acipenser sinensis, the Chinese sturgeon, may either be incorrectly identified or the result of undocumented hybridization with A. gueldenstaedtii. Recently, new material with vouchered specimens has been collected and investigated with DNA sequence data from four mtDNA loci to test whether the published mitogenome of A. sinensis was recovered in the same clade with the new vouchered material. This example reinforces the need for voucher specimens and materials for genetic sequence data.
      PubDate: 2014-09-06T02:23:55.803371-05:
      DOI: 10.1111/jai.12568
       
  • Modelling attempts utilized in sturgeon research: a review of the
           state‐of‐the art
    • Authors: I. Jarić; J. Gessner, M.‐L. Acolas, P. Lambert, E. Rochard
      Abstract: The objective of this paper was to understand trends in modelling over time within sturgeon research and the effects of modelling applications on the scientific community using a bibliometric approach on articles from the ISI Web of Knowledge online database between 1996 and 2012. The results indicate an increasing contribution of modelling within the general field of sturgeon research. The population models analyzed mainly focused upon the impacts of fisheries, dams, stocking, genetics and elasticity/sensitivity analyses. Habitat suitability models, hydrodynamic models, bioenergetic models and general statistical models focused on the effects of habitat availability, species distribution, survival, growth and spawning migrations. The largest number of publications originated from North America, with a regional focus on the West Coast and Mississippi/Great Lakes regions. In contrast, model development and application was lacking for the Aral Sea region and Siberia. Moreover, thus far there were no published population models for north‐western European and Mediterranean sturgeon populations. The models have only been applied to a limited number of species and, with an increased Red List status of a species, the number of publications decreased substantially. Such results should be considered as a warning sign with regard to the effective implementation of conservation strategies for endangered species, given that the development of models is considered a key tool for the optimization of management and protection measures.
      PubDate: 2014-09-06T02:23:38.622874-05:
      DOI: 10.1111/jai.12572
       
  • Toxicity of smelter slag‐contaminated sediments from Upper Lake
           Roosevelt and associated metals to early life stage White Sturgeon
           (Acipenser transmontanus Richardson, 1836)
    • Authors: E. E. Little; R. D. Calfee, G. Linder
      Pages: n/a - n/a
      Abstract: The toxicity of five smelter slag‐contaminated sediments from the upper Columbia River and metals associated with those slags (cadmium, copper, zinc) was evaluated in 96‐h exposures of White Sturgeon (Acipenser transmontanus Richardson, 1836) at 8 and 30 days post‐hatch. Leachates prepared from slag‐contaminated sediments were evaluated for toxicity. Leachates yielded a maximum aqueous copper concentration of 11.8 μg L−1 observed in sediment collected at Dead Man's Eddy (DME), the sampling site nearest the smelter. All leachates were nonlethal to sturgeon that were 8 day post‐hatch (dph), but leachates from three of the five sediments were toxic to fish that were 30 dph, suggesting that the latter life stage is highly vulnerable to metals exposure. Fish maintained consistent and prolonged contact with sediments and did not avoid contaminated sediments when provided a choice between contaminated and uncontaminated sediments. White Sturgeon also failed to avoid aqueous copper (1.5–20 μg L−1). In water‐only 96‐h exposures of 35 dph sturgeon with the three metals, similar toxicity was observed during exposure to water spiked with copper alone and in combination with cadmium and zinc. Cadmium ranging from 3.2 to 41 μg L−1 or zinc ranging from 21 to 275 μg L−1 was not lethal, but induced adverse behavioral changes including a loss of equilibrium. These results suggest that metals associated with smelter slags may pose an increased exposure risk to early life stage sturgeon if fish occupy areas contaminated by slags.
      PubDate: 2014-09-04T02:28:46.19732-05:0
      DOI: 10.1111/jai.12565
       
  • Sound production of spawning lake sturgeon (Acipenser fulvescens
           Rafinesque, 1817) in the Lake Winnebago watershed, Wisconsin, USA
    • Authors: C. Bocast; R. M. Bruch, R. P. Koenigs
      Pages: n/a - n/a
      Abstract: The primary goal of this study was to obtain accurate data of previously undocumented lake sturgeon (Acipenser fulvescens Rafinesque, 1817) spawning sounds, generated during wild sturgeon reproduction. Biologists have long known that lake sturgeon produce low‐frequency sounds during spawning bouts; energy from these sounds can break the surface of the water occasionally and propagate harmonics in the terrestrial atmosphere, creating a faint drumming popularly known as ‘sturgeon thunder’. Understanding the contribution of this sonic behavior in context is essential for gaining a more comprehensive scientific appreciation of the process of sturgeon spawning, and accurate acoustic data should prove useful for fisheries managers seeking to monitor or enhance sturgeon stocks for reproductive activity. Recordings were made at several locations on the Wolf and Embarrass rivers during the 2011–2013 spawning seasons. Drumming sounds ranging from 5 to 8 Hz fundamental frequency were evident. Other characteristic noises associated with spawning lake sturgeon, including low‐frequency rumbles and hydrodynamic sounds, were identified. Other high frequency sounds were also discovered. All of these sounds coalesce into a distinctive acoustic signature of lake sturgeon spawning activity. Knowledge of this sonic signature can be used to accurately document reproductive activity at multiple locations over extended periods using remote recording tools and techniques.
      PubDate: 2014-09-04T02:17:35.651628-05:
      DOI: 10.1111/jai.12556
       
  • Seasonal changes in oocyte maturational competence, ovulatory competence
           and gonadotropin sensitivity of ovarian follicles in hybrid sturgeon,
           bester (Huso huso × Acipenser ruthenus)
    • Authors: M. Ishihara; B. Tokui, T. Abe, S. Ijiri, S. Adachi
      Pages: n/a - n/a
      Abstract: Oocyte maturation and ovulation in sturgeon species are induced by injection of hormones such as the luteinizing hormone‐releasing hormone (LHRH). Appropriate timing for the LHRH injection is determined by monitoring the maturational stage of the ovarian follicles. In the present study, ovarian follicles from a group of female bester sturgeon (Huso huso × Acipenser ruthenus) were sampled continuously from September to May and incubated in 100% L‐15 medium (pH 8.2) containing 17α‐hydroxyprogesterone or salmon pituitary extract (SPE) for 48 h at 15°C. After incubation, ratios of oocyte maturational competence (OMC; ability of oocytes to undergo final oocyte maturation in response to maturation‐inducing steroid, MIS), ovulatory competence (OC; ability of ovarian follicles to ovulate under MIS stimulation), and GTH sensitivity (ability of ovarian follicles to respond to GTH) were examined. Almost all oocytes maintained OMC throughout the sampling period. However, OC was acquired in circa December and May. The ratio of follicles that acquired ovulatory competence showed wide variation among individuals. Most females first acquired a higher degree of ovulatory competence in May, although some only did so around December. SPE‐induced oocyte maturation was relatively high throughout the entire experiment, and the ovulation rate showed a tendency similar to that of the ovulatory competence. LHRH‐a injections in May successfully induced ovulation in all females. Higher hatching rates resulted in females whose ovarian follicles showed an increasing trend of ovulatory competence and GTH sensitivity for ovulation in May. These results indicate that ovulatory competence and GTH sensitivity can be used as indicators to determine the timing of LHRH injections for sturgeon.
      PubDate: 2014-09-03T02:43:35.252178-05:
      DOI: 10.1111/jai.12579
       
  • Identification of genes involved in gonadal sex differentiation and the
           dimorphic expression pattern in undifferentiated gonads of Russian
           sturgeon Acipenser gueldenstaedtii Brandt & Ratzeburg, 1833
    • Authors: S. Hagihara; R. Yamashita, S. Yamamoto, M. Ishihara, T. Abe, S. Ijiri, S. Adachi
      Abstract: The establishment of a sexing technique at an early developmental stage is an important issue in sturgeon aquaculture, yet the mechanism of sex differentiation in sturgeons remains poorly understood. This study aimed to identify genes involved in gonadal sex differentiation and to investigate sexually dimorphic gene expression in undifferentiated gonads. RNA‐seq analyses using next‐generation sequencers were carried out on undifferentiated gonads of five 9‐month‐old juvenile Russian sturgeon Acipenser gueldenstaedtii. A total of 45 686 832 (8498 Mb) and 79 743 269 (7887 Mb) quality‐controlled reads were obtained using Ion PGM and HiSeq 2000 sequencers, respectively, and were assembled into 338 648 contigs (N50: 532 b). tBLASTx analyses identified 26 transcripts potentially involved in gonadal differentiation. Read‐mapping analyses were performed to obtain relative transcript levels (RPKM values). Multivariate analyses of the RPKM values of five transcripts (gsdf, dmrt1a, dmrt1b, foxl2 and cyp19a1a) showed that the five individuals could be separated into two distinct groups. One group, comprising two individuals, had increased levels of foxl2, hsd17b1 and cyp19a1a, suggesting differentiation into females. Alternatively, levels of gsdf were higher in the other three individuals, suggesting differentiation into males. We describe the levels of 26 transcripts potentially involved in gonadal differentiation in undifferentiated sturgeon gonads and suggest that levels of gsdf, foxl2, hsd17b1 and cyp19a1a are appropriate sexing markers for sturgeon at an early developmental stage.
      PubDate: 2014-08-30T03:33:37.137056-05:
      DOI: 10.1111/jai.12588
       
  • Proximate composition and fatty acid profile in different tissues of wild
           female Chinese sturgeon (Acipenser sinensis Gray, 1835)
    • Authors: C. Song; P. Zhuang, L. Z. Zhang, T. Zhang, J. Y. Liu
      PubDate: 2014-08-30T03:33:22.658434-05:
      DOI: 10.1111/jai.12583
       
  • Relative recruitment success of stocked age‐1 vs age‐0 lake
           sturgeon (Acipenser fulvescens Rafinesque, 1817) in the Nelson River,
           northern Canada
    • Authors: C. A. McDougall; D. J. Pisiak, C. C. Barth, M. A. Blanchard, D. S. MacDonell, D. Macdonald
      Abstract: Success of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) stocking programmes has rarely been evaluated. As of the early 1990s, Lake Sturgeon populations were nearly extirpated from several sections of the upper Nelson River, Manitoba, at least in part due to historical overexploitation. Between 1994 and 2011, 20 885 fingerlings (age‐0, untagged) and 1117 yearlings (age‐1, 1014 PIT tagged) were stocked into an upper Nelson River reach. In fall 2012, a Lake Sturgeon population inventory using gill nets assessed post‐release survival/retention of stocked fish. Of 91 unique Lake Sturgeon captured, 67 (74%) possessed PIT tags, signifying they were stocked at age‐1. Relative recruitment success was conservatively estimated to be 17.7 times greater for age‐1 vs age‐0 stocked fish based only on PIT tag recapture data. However, including 19 additional fish identified as stocked at age‐1 based on atypical ‘first’ annuli patterns, the revised relative recruitment success rate was 130 times greater for age‐1 vs age‐0. An interpreted consensus ageing method produced correct age assignment 97% of the time for juveniles of known age, despite complications caused by overwinter growth in the hatchery.
      PubDate: 2014-08-30T03:32:02.860725-05:
      DOI: 10.1111/jai.12555
       
  • Effects of Ca and Mg concentrations in seawater on the growth and energy
           
    • Authors: M. L. Wang; X. M. Zhang, T. X. Gao, P. D. Zhang
      Abstract: Effects of seawater calcium (Ca) and magnesium (Mg) concentrations on the growth and energy budget of juvenile Paralichthys olivaceus (Temminck & Schlegel, 1846) were investigated at 20°C and a salinity of 30 psu. The Ca/Mg ratio (Ca : Mg = 1 : 3) in the experimental water was kept constant. Five treatments were set: C1, C2, C3, C4, and C5, and the Ca and Mg concentrations were 700, 1100, 1600, 2200, and 2800 (mg L−1), respectively. After a 60‐day feeding trial the P. olivaceus survival rates were not affected significantly by Ca or Mg concentrations in the range of 700–2800 mg L−1. However, the specific growth rates (SGR) and weight gain (WG) of all treatments decreased with ascending Ca and Mg concentrations. The Ca and Mg concentrations had a strong influence on various energy parameters, namely, energy deposited for growth (G), energy lost for respiration (R), and energy lost in excretion (U), but had little influence on energy lost in feces (F). This indicated that the growth rate differences under different concentrations of Ca and Mg mainly resulted from differences of assimilation efficiency and energy channeled into respiration. The highest net growth efficiency was attained at the lowest concentration of Ca and Mg in seawater, and the higher concentrations of Ca and Mg increased the energy channeled to respiration and excretion, which led to significant reduction in growth. Therefore, the optimal growth of P. olivaceus could be obtained by regulating the concentration of Ca and Mg at 700 mg L−1, where the average energy budget was: 100C (100% energy consumed in food) = 47.21 (±0.63) G + 32.89 (±0.42) R + 16.71 (±0.56) F + 3.19 (±0.05) U.
      PubDate: 2014-08-30T03:31:45.303419-05:
      DOI: 10.1111/jai.12477
       
  • Using mark‐recapture data in an individual‐based model to
           evaluate length‐at‐age differences between two Snake River
           white sturgeon (Acipenser transmontanus Richardson, 1836) populations in
           Idaho, USA
    • Authors: P. Bates; J. Chandler, K. Lepla, K. Steinhorst
      Abstract: Despite showing similar abundance estimates, population surveys of wild white sturgeon (Acipenser transmontanus Richardson, 1836) in the Bliss and Hells Canyon reaches of the Snake River display very different stock structures. To better understand these differences, an individual based model was developed using empirical mark‐recapture metrics from 343 white sturgeon recaptured in the Bliss reach [at‐large 1.0–19.9 years], and 580 white sturgeon recaptured in the Hells Canyon reach [at‐large 1.0–21.2 years]. After calculating annual growth increments from these recaptures, individuals from each reach were assigned to size bins then randomly chosen from within each bin to ‘grow’ theoretical fish. This process was bootstrapped 1000 times, producing a mean length‐at‐age trajectory for each reach. From these data, mark‐recapture samples were assigned estimated ages and fitted to a three‐parameter logistic growth curve. Results indicate a wide disparity in length‐at‐age of white sturgeon between reaches, with the Bliss population displaying an intrinsic rate of increase [K = 0.118] twice that of the Hells Canyon population [K = 0.059]. This is due primarily to slow juvenile growth in the Hells Canyon population relative to juvenile growth in the Bliss population. The much slower growth rate of juveniles in the Hells Canyon reach has consequences to population demographics, such as age at first maturity. Although growth differences are large, both populations appear to be stable or increasing in abundance despite being regulated by very different mechanisms.
      PubDate: 2014-08-25T04:57:12.015752-05:
      DOI: 10.1111/jai.12557
       
  • Historical biomass and sustainable harvest of Great Lakes lake sturgeon
           (Acipenser fulvescens Rafinesque, 1817)
    • Authors: T. Haxton; G. Whelan, R. Bruch
      Abstract: Historical abundance and biomasss of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) in the Great Lakes were estimated from historical commercial harvest data from 1879 to 1920 using two modeling techniques: a surplus production model with a Bayesian approach, and a depletion model. In addition, theoretical sustainable levels of exploitation and temporal recovery periods were estimated based on the surplus production model. The historical biomass of Lake Sturgeon in the Great Lakes during the period from 1879 to 1885 varied for each model and ranged from 313 900 to 6 473 000 kg (0.5–16.7 kg ha−1) using the surplus production model to 968 000 to 25 414 000 kg (2.4–31.7 kg ha−1) using the depletion model. The intrinsic population growth rate as determined from the surplus production model ranged from 0.079 to 0.123, and the theoretical sustainable exploitation rate ranged from 2.0 to 3.1%. The predicted recovery period for the overexploited populations was in excess of 60 years given recruitment assuming all other impediments to population recovery were removed.
      PubDate: 2014-08-25T04:46:10.195223-05:
      DOI: 10.1111/jai.12569
       
  • The effect of essential fatty acid (EFA) enrichment of Artemia sp. nauplii
           on the enzymatic activity of Atlantic sturgeon (Acipenser oxyrinchus
           Mitchill, 1815) larvae – preliminary study
    • Authors: M. Kamaszewski; M. Wójcik, T. Ostaszewska, R. Kasprzak, R. Kolman, M. Prusińska
      PubDate: 2014-08-23T02:30:34.482873-05:
      DOI: 10.1111/jai.12561
       
  • Variation in lake sturgeon (Acipenser fulvescens Rafinesque, 1817)
           abundance in rivers across Ontario, Canada
    • Authors: T. Haxton; M. Friday, T. Cano, C. Hendry
      Abstract: The objectives of this study were to (i) assess the variation in relative abundance of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) subjected to various man‐induced stresses and physical characteristics at a landscape scale across Ontario; and (ii) ascertain the factors that explain the variability observed among rivers using a multivariate approach. A standardized index netting program targeting juvenile and adult Lake Sturgeon was conducted over two field seasons at 22 river sites across Ontario. Each river had unique or different human‐induced stresses and physical characteristics. Relative abundance of Lake Sturgeon varied in river across the Ontario landscape. A principal component analysis was conducted using site physical characteristics with the associated anthropogenic stressors. The catch‐per‐unit‐effort (CPUE) for juvenile and adult Lake Sturgeon were then regressed with the scores of principal components having eigenvalues >1. The variation observed was best explained by the negative relationship observed between CPUE and the presence of hydroelectric generating stations. Historical commercial fisheries also had an effect on Lake Sturgeon abundance whereas subsistence fisheries seemed to focus on rivers that were not regulated and where Lake Sturgeon numbers were greater. Research and recovery efforts should focus on minimizing the impact of hydroelectric generation on Lake Sturgeon while achieving socioeconomic goals.
      PubDate: 2014-08-23T02:29:40.660359-05:
      DOI: 10.1111/jai.12550
       
  • Induced spawning of wild‐caught adult lake sturgeon: assessment of
           hormonal and stress responses, gamete quality, and survival
    • Authors: J. Genz; C. A. McDougall, D. Burnett, L. Arcinas, S. Khetoo, W. G. Anderson
      Abstract: This research assessed the endocrine and physiological effects of Ovaprim™ and synthetic homologous sturgeon gonadotrophic releasing hormone (GnRH) on spawning male and female adult lake sturgeon, Acipenser fulvescens (Rafinesque, 1817). Wild‐caught adults were administered Ovaprim, GnRH, or Ringers solution (control), and serial blood samples were collected for up to 27 days following capture and hormone administration. Circulating cortisol levels appeared to increase following administration of both hormonal treatments. However, circulating cortisol was higher and plasma pH lower at capture than at any other time for all treatments, indicating that capture and transport stress were the largest disrupting factors, more so than the effects of induced spawning. Plasma concentrations of estradiol and testosterone in both sexes were similar to previously reported values. In all treatments the circulating estradiol and testosterone never significantly exceeded the values at capture prior to endocrine manipulation of the reproductive axis. Similarly, testosterone in males and estradiol in females in the muscle tissue were consistently at the same or lower concentrations than at capture. The apparent survival of all of the study animals following return to their native river indicated that the stress effects from capture and induced spawning were not severe. In concert, our results suggest that hormonal injections can be used to aid in gamete collection from wild A. fulvescens, without negative effects on long‐term broodstock survival. Hatching success, larval survival to the juvenile stage, egg diameter, and concentrations of protein, triglyceride, and glucose in the egg, sperm, and ovarian fluid (but not seminal plasma), were the same or greater in GnRH‐treated fish than gametes from the Ovaprim‐treated group, suggesting that utilization of GnRH may be preferable to other common methods of spawning induction.
      PubDate: 2014-08-23T02:29:26.035759-05:
      DOI: 10.1111/jai.12548
       
  • Population characteristics of pallid sturgeon, Scaphirhynchus albus
           (Forbes & Richardson, 1905), in the lower Platte River, Nebraska
    • Authors: M. J. Hamel; M. A. Pegg, J. J. Hammen, M. L. Rugg
      Abstract: Pallid sturgeon, Scaphirhynchus albus (Forbes & Richardson, 1905), have been studied intensively in recent years to understand a declining adult population that does not seem to be naturally reproducing; however, most of this effort has occurred in the main‐stem Missouri and lower Mississippi rivers. Pallid sturgeon are known to occupy tributary streams intermittently, but the importance of tributaries for completion of essential life stages for pallid sturgeon remains unknown. Tributaries may provide uses for fish spawning and reproduction, nursery or refuge habitat, and areas for foraging. Therefore pallid sturgeon population characteristics were studied in the Platte River, Nebraska, a large tributary to the Missouri River. During 2009–2012 137 pallid sturgeon were captured. Pallid sturgeon were found throughout the lower 159 km of the Platte River throughout the entire year (March–November); however, pallid sturgeon were more abundant in the lower‐most 52 km during 2009 and 2010. Capture locations were in comparatively deeper water along flow gradients between the thalweg and mid‐channel sandbars. Most pallid sturgeon were of hatchery origin and dispersed an average of 197.5 km (±233 SD) from the original stocking location to the Platte River capture site. Although the direct reasons for are unknown, the lower Platte River may be providing habitat or resources that are not typically found in the channelized Missouri River. Continued research in the Platte River and other large tributaries may provide insight for recovery of endemic, large‐river species. Persistence of large‐river fishes may depend on population connectivity at multiple scales; identifying these connections is critical.
      PubDate: 2014-08-22T05:27:28.83838-05:0
      DOI: 10.1111/jai.12560
       
  • Morphometric comparisons of the Gulf sturgeon (Acipenser oxyrinchus
           desotoi Mitchill, 1815) in western and eastern population extremes
    • Authors: P. F. Mickle; M. S. Peterson, J.‐M. Havrylkoff, P. O. Grammer
      Abstract: The Gulf sturgeon, Acipenser oxyrinchus desotoi Mitchill 1815, is an anadromous fish native to the Gulf of Mexico (GOM). This threatened species ascend northern GOM rivers ranging from the Pearl River, Louisiana to the Suwannee River, Florida. The drainage fidelity seen within this species coupled with the complex migration patterns create many unknowns concerning the functionality between drainages and size classes. Being a threatened species that cannot be sacrificed, morphometric measurements are difficult to acquire due to minimized handling times and non‐lethal data collection methods. Seven morphometric measurements of Gulf sturgeon were compared between western and eastern GOM rivers and multiple size classes (juvenile, sub‐adult, and adult). Principal Component, Discriminant Function, and Maximum Chance Criterion analyses were conducted and identified differentiating morphometrics and classified groupings among size classes and rivers of Gulf sturgeon. This morphometric approach has the potential to be used in parallel with molecular findings and should allow managers to identify sub‐populations for a variety of threatened and endangered species.
      PubDate: 2014-08-22T05:27:06.712903-05:
      DOI: 10.1111/jai.12559
       
  • Population size of pallid sturgeon, Scaphirhynchus albus (Forbes &
           Richardson, 1905), in the lower Missouri River near Kansas City, Missouri,
           USA
    • Authors: K. R. Winders; K. D. Steffensen
      Abstract: The objectives of this study were to investigate the population size of hatchery‐reared and wild pallid sturgeon, Scaphirhynchus albus (Forbes & Richardson, 1905), in a 43.3 river kilometer (rkm) reach of the Missouri River downstream of Kansas City, Missouri, USA and compare these with previous published estimates. This reach has been shown to represent the abundance and distribution of the pallid sturgeon population throughout the lower Missouri River, and was therefore chosen for this study in order to monitor progress towards recovering this federally endangered species. The robust‐design approach was used within the Program MARK using mark‐recapture data of fish sampled from 2011 to 2013. The annual population estimates of pallid sturgeon varied from 6.1 to 11.1 fish/rkm, of which known hatchery‐origin pallid sturgeon (5.5 to 10.2 fish/rkm) were much more abundant than those of wild origin (0.6 to 0.9 fish/rkm). These population estimates are drastically fewer than those published for another reach of the lower Missouri River and represent far less advancement (12–18%) towards meeting the five wild adult fish/rkm criteria for considering reclassification of pallid sturgeon.
      PubDate: 2014-08-19T01:10:26.110624-05:
      DOI: 10.1111/jai.12558
       
  • Identification of a robust Lake Sturgeon (Acipenser fulvescens Rafinesque,
           1917) population in Goulais Bay, Lake Superior
    • Authors: T. C. Pratt; W. M. Gardner, J. Pearce, S. Greenwood, S. C. Chong
      Abstract: Lake Sturgeon (Acipenser fulvescens Rafinesque, 1917) in Lake Superior are greatly depressed from their historic abundance, and few populations meet the rehabilitation goals identified by management agencies. A netting program targeting juvenile Lake Sturgeon (ages 3–15) was implemented from 2010 to 2012 in Goulais Bay, a shallow, productive bay in the south‐eastern part of the lake, to determine abundance, distribution, population characteristics (size structure, condition, age structure, mortality and growth), and recruitment patterns. Five‐hundred and thirty‐one individuals were captured over the 3‐year study, resulting in a mark‐recapture estimate of 4977 (95% CIs 3295–7517) juveniles. Catch rates in this study were higher than in any other location in Lake Superior, with sturgeon being broadly distributed around the bay. Estimated annual survival rate ranged from 0.691 to 0.858, depending on the method used. The majority of fish captured were between 620 and 800 mm in total length and were between 4 and 10 years of age (range 1–29 years). Recruiting year‐classes were apparent every year, with no apparent effects due to lampricide treatments (a suspected threat to age‐0 Lake Sturgeon) in the Goulais River. Year‐class strength was positively related to spring water levels. It is possible that this robust Goulais Bay population could help re‐populate the south‐eastern part of Lake Superior, which contains a number of large, productive embayment areas that formerly supported large Lake Sturgeon populations.
      PubDate: 2014-08-19T01:08:59.291922-05:
      DOI: 10.1111/jai.12566
       
  • Effect of temperature and substrate on whole body cortisol and size of
           larval white sturgeon (Acipenser transmontanus Richardson, 1836)
    • Authors: L. C. Bates; M. A. Boucher, J. M. Shrimpton
      Abstract: White sturgeon (Acipenser transmontanus Richardson, 1836) larvae were reared at two temperatures (13.5 or 17.5°C) with or without gravel as a substrate to examine the effect of rearing environment on growth and whole body cortisol, an index of stress (initial weight 23.4 mg; four replicate tanks per treatment). Larvae were sampled 8, 16, and 24 days post‐hatch. Larvae were larger when reared with substrate and at warmer temperatures. For whole body cortisol, a significant age by temperature interaction was observed with the highest values on day 16 for larvae from warm water treatments. Larvae reared in gravel consistently showed significantly lower whole body cortisol than larvae reared without substrate. In response to mechanical agitation, there was a significant effect of time following disturbance. Increased growth and reduced stress hormone levels make substrate rearing of yolksac larvae an important technique for enhancement efforts in artificial and natural environments. The positive effects of temperature on growth, however, with higher whole body cortisol, suggest that larval white sturgeon development may be better at cooler temperatures.
      PubDate: 2014-08-19T01:08:41.777671-05:
      DOI: 10.1111/jai.12570
       
  • Spawning migrations and reproductive parameters of the kaluga sturgeon,
           Huso dauricus (Georgi, 1775), and Amur sturgeon, Acipenser schrenckii
           (Brandt, 1869)
    • Authors: V. N. Koshelev; G. Ruban, A. Shmigirilov
      Abstract: Mature specimens of kaluga sturgeon Huso dauricus (Georgi, 1775) and Amur sturgeon Acipenser schrenckii (Brandt, 1869) were previously abundant in catches throughout their range that included the Amur River basin and coastal waters of the Sea of Okhotsk and Sea of Japan. However, both kaluga and Amur sturgeon now reach maturity mainly in the Amur Estuary and sea waters. The most intensive migration from the estuary to the river takes place in spring, from mid‐May to mid‐June (with a peak 21–25 May), and in autumn, from mid‐August to late September (with a peak 16–25 August). The migration of kaluga and Amur sturgeon spawners is anadromous. Spring spawners numerically prevail over autumn spawners in the kaluga sturgeon, whereas an inverse situation is observed in the Amur sturgeon. Average body sizes of females in both species and that of male kaluga sturgeon have decreased over the past 5–10 years. The Amur and kaluga sturgeons from the Amur River mature earlier than those from the Amur Estuary. The average absolute fecundity of both species has decreased in recent years because of a reduction in the proportion of spawners in older age classes.
      PubDate: 2014-08-18T07:55:46.598336-05:
      DOI: 10.1111/jai.12549
       
  • Non‐lethal gill biopsy of juvenile hybrid sturgeon (Acipenser
           ruthenus ♀ × A. schrenckii ♂): validity
           and impact on growth and osmoregulation
    • Authors: F. Zhao; P. Zhuang, T. Zhang, L. Zhang, J. Liu, J. Hou
      Abstract: The objective of this study was to validate a gill biopsy method for non‐lethal monitoring of the osmoregulatory status of young sturgeon in estuary areas. After gill biopsy, hybrid sturgeon (Acipenser ruthenus ♀ × A. schrenckii ♂) were transferred from freshwater to brackish water (10 ppt) for 6 weeks. Mortality, serum osmolality, ion concentrations and gill Na+, K+‐ATPase activity of fish exposed to brackish water was measured. No detrimental effects on subsequent survival, growth or osmoregulation of hybrid sturgeon were observed.
      PubDate: 2014-08-18T07:55:32.431904-05:
      DOI: 10.1111/jai.12554
       
  • An AFLP‐based approach for the identification of sex‐linked
           markers in Amur sturgeon Acipenser schrenckii Brandt, 1869
    • Authors: T.‐Q. Xiao; C.‐Y. Lu, C. Li, L. Cheng, D.‐C. Cao, X.‐W. Sun
      Abstract: Sturgeon species are widely known for their caviars. A large part of the expense associated with caviar production is due to the length of time individuals must be reared before reaching maturity. Sex identification at an early age would reduce costs of broodstock rearing. A DNA AFLP‐fingerprinting approach was used to identify sex‐specific markers and sex‐associated markers that exhibit a difference between female and male Amur sturgeon Acipenser schrenckii Brandt, 1869. AFLP analysis of six females and six males using 64 primer combinations yielded a total of 7116 AFLP bands of which 1264 (17.76%) bands were polymorphic. The polymorphism exhibited differences between female (15.64%) and male (16.34%) groups. Sex‐specific markers were not detected among the AFLP bands. However, 42 presumed sex‐associated bands that exhibited large differences between females and males were identified in 34 primer combinations. None of the 28 SCAR markers derived from the 39 sequences exhibited sex specificity when tested against 15 females and 15 males. Nevertheless, five SCAR markers exhibited a significant difference between the sexes. Sequence analysis using blastn in GenBank revealed high homology for 10 fragments, among which C4 was associated with the secretion of prolactin in mammals, but was not sex‐specific based on testing of SCAR markers. The five SCAR markers and the clone C4 may represent candidate genes for future research of sex specificity.
      PubDate: 2014-08-18T07:45:35.924163-05:
      DOI: 10.1111/jai.12553
       
  • Clearhead icefish, (Protosalanx hyalocranius Abbott, 1901) (Salmoniformes,
           Salangidae), a new non‐native species has established a population
           in the Amur River, China
    • Authors: F. J. Tang; W. Liu, J. L. Wang, J. Henne, X. S. Cui
      PubDate: 2014-08-14T06:29:30.065471-05:
      DOI: 10.1111/jai.12454
       
  • Linking movements of lake sturgeon (Acipenser fulvescens Rafinesque, 1817)
           in a small hydroelectric reservoir to abiotic variables
    • Authors: C. A. McDougall; P. J. Blanchfield, W. G. Anderson
      Abstract: Quantifying the extent to which abiotic factors influence lake sturgeon (Acipenser fulvescens Rafinesque, 1817) movement and utilization of areas where they are susceptible to entrainment may be useful for management of hydroelectric operations. Over two open–water seasons, acoustic telemetry was used to monitor tagged adults (n = 25) and subadults (n = 24) throughout a 9.8 km long run‐of‐the‐river reservoir located on the Winnipeg River, Manitoba, Canada. Movement and utilization patterns were examined for correlation with abiotic variables. Despite considerable individuality, the adult sample population increasingly utilized the lower sections of the reservoir when air and water temperatures were high, daylight hours were long, river flow was increasing, and flows were high. However, our hypothesis of a pronounced concentration of Lake Sturgeon occurring immediately upstream of the generating station when high flows coincided with the summer/fall period was not supported. This may be attributed to the presence of a shallow river narrows located 2.1 km upstream of the station, which appeared to restrict the extent of seasonal/flow influenced downstream movement by adults. Movements of individual subadults were also correlated to seasonal and flow variables, but directionality was not consistent and population level trends in utilization did not appear to be correlated to abiotic variables. Results suggest that in small reservoirs, adult utilization of the areas immediately upstream of hydroelectric facilities may be influenced more by seasonality than by flow conditions.
      PubDate: 2014-08-13T07:38:44.391619-05:
      DOI: 10.1111/jai.12546
       
  • Biochemical comparison between eggs from female Chinese sturgeon
           (Acipenser sinensis Gray, 1835) reconditioned in freshwater and eggs from
           wild females: evaluation of female reconditioning as a conservation
           culture technique
    • Authors: L. Wei; W. Qiwei, S. Li
      Abstract: Chinese sturgeon (Acipenser sinensis Gray, 1835) eggs from wild females (‘wild eggs’) and eggs from females reconditioned in freshwater (‘freshwater eggs’) were compared for biochemical factors related to their good chemical and physical condition and successful fertilization. Dry weights did not differ between the two groups of eggs. Wild eggs had a significantly higher protein content but lower lipid content than freshwater eggs. There were multiple and significant differences in the fatty acids between eggs from the two groups, but there was no difference for vitellin (Vn). The levels of phosphorus (P), magnesium (Mg), vitamin A (VA) and vitamin E (VE) in wild eggs were significantly higher than in freshwater eggs, but calcium (Ca) and zinc (Zn) levels did not differ between the two groups. These results can be used to discriminate wild eggs and reconditioned eggs. Also suggested is to decrease lipids and increase protein levels in freshwater eggs for better egg quality. Mg, P, VA and VE should also be given as sturgeon food supplements.
      PubDate: 2014-08-13T07:38:28.871246-05:
      DOI: 10.1111/jai.12547
       
  • Predicted effects of future climate warming on thermal habitat suitability
           for Lake Sturgeon (Acipenser fulvescens, Rafinesque, 1817) in rivers in
           Wisconsin, USA
    • Authors: J. Lyons; J. S. Stewart
      Abstract: The Lake Sturgeon (Acipenser fulvescens, Rafinesque, 1817) may be threatened by future climate warming. The purpose of this study was to identify river reaches in Wisconsin, USA, where they might be vulnerable to warming water temperatures. In Wisconsin, A. fulvescens is known from 2291 km of large‐river habitat that has been fragmented into 48 discrete river‐lake networks isolated by impassable dams. Although the exact temperature tolerances are uncertain, water temperatures above 28–30°C are potentially less suitable for this coolwater species. Predictions from 13 downscaled global climate models were input to a lotic water temperature model to estimate amounts of potential thermally less‐suitable habitat at present and for 2046–2065. Currently, 341 km (14.9%) of the known habitat are estimated to regularly exceed 28°C for an entire day, but only 6 km (0.3%) to exceed 30°C. In 2046–2065, 685–2164 km (29.9–94.5%) are projected to exceed 28°C and 33–1056 km (1.4–46.1%) to exceed 30°C. Most river‐lake networks have cooler segments, large tributaries, or lakes that might provide temporary escape from potentially less suitable temperatures, but 12 short networks in the Lower Fox and Middle Wisconsin rivers totaling 93.6 km are projected to have no potential thermal refugia. One possible adaptation to climate change could be to provide fish passage or translocation so that riverine Lake Sturgeon might have access to more thermally suitable habitats.
      PubDate: 2014-08-11T04:22:58.670483-05:
      DOI: 10.1111/jai.12543
       
  • Comparing commercial and recreational harvest characteristics of
           paddlefish Polyodon spathula (Walbaum, 1792) in the Middle Mississippi
           River
    • Authors: R. N. Hupfeld; Q. E. Phelps
      Abstract: Here we contrast the relative influence of the commercial and recreational harvest sectors on the Middle Mississippi River paddlefish Polyodon spathula (Walbaum, 1792) population. We performed a creel survey of randomly selected commercial fishers and recreational anglers to gather characteristic harvest information to make comparisons between sectors. We found that the commercial sector harvested predominately large, mature paddlefish. Conversely, the recreational sector tended to harvest a greater proportion of small, immature paddlefish. Because these sectors are harvesting different portions of the population, the relative influence on the dynamic rate functions and potential conflict between sectors must be taken into account for fishery management decisions. One approach would be to increase the minimum length limit, to allow for equal harvest between the commercial and recreational harvest sectors. Ultimately, this will allow for both harvest sectors to harvest the same portion of the population, as well as increase the reproductive potential of the population. Additionally, obtaining an accurate assessment of the catch and effort for both sectors is imperative for the management and allocation of a shared resource.
      PubDate: 2014-08-07T02:20:20.962218-05:
      DOI: 10.1111/jai.12552
       
  • The effect of multi‐year vs single‐year stocking on lake
           sturgeon (Acipenser fulvescens Rafinesque, 1817) genetic diversity
    • Authors: A. B. Welsh; J. R. Jackson
      Abstract: Many lake sturgeon (Acipenser fulvescens Rafinesque, 1817) populations in the Great Lakes have not recovered from previous threats, whereby stocking can increase population abundances. Stocking in Oneida Lake, New York used two approaches: single‐year stocking using sturgeon from the Des Prairies River and multi‐year stocking using sturgeon from the St. Lawrence River. Stocked A. fulvescens were sampled and assigned to their corresponding stocking strategy based on age. Samples were analyzed at 12 microsatellite loci to evaluate how a single year of stocking (N = 273) and multiple years of stocking (N = 100) affected genetic diversity and effective population size (Ne). Single‐year stocking resulted in lower genetic diversity, likely due to a small number of parents. Multi‐year stocking retained most of the genetic diversity of the source population, compensating for the few parents available in a single year. Although multi‐year stocking resulted in a higher Ne, the Ne:N ratio was lower (0.34) compared to single‐year stocking (0.65), likely due to unequal sex ratios and family size variance across years. It is recommended that stocking of Lake Sturgeon take place over several years. However, consistent numbers need to be stocked each year and family size should be equalized across cohorts in order to maximize Ne.
      PubDate: 2014-08-02T01:08:31.620494-05:
      DOI: 10.1111/jai.12544
       
  • The need for genetic support in restocking activities and ex situ
           conservation programmes: the case of the Adriatic sturgeon (Acipenser
           naccarii Bonaparte, 1836) in the Ticino River Park
    • Authors: E. Boscari; L. Congiu
      Abstract: The Adriatic sturgeon (Acipenser naccarii Bonaparte, 1836), endemic to the North Adriatic region, was recently reclassified by IUCN as ‘Critically endangered and possibly extinct in the wild’ since no natural spawning has been recorded in the last 20 years. Its survival relies on restocking activities originating from a single captive broodstock collected by a private aquaculture plant (V.I.P.) in the 1970s and is currently reduced to 13 individuals. Few alternative brood‐stocks of F1 animals have been retained for use in the near future. Thus far, brood‐stocks, as well as all stocks released in the wild, have been randomly chosen without regard to their genetic composition. The consequence of breeding programmes with no genetic input was evaluated in the Ticino River Park (TRP) in Italy. A parental allocation procedure based on microsatellite markers useful for tetraploids was used following a Band‐Sharing approach. Levels of relatedness within the TRP F1 captive breeders (Stock_1) and among animals released by TRP in the past (Stock_2) were explored and compared with the stock of wild origin. The pronounced decrease in genetic diversity observed in the analysed sample suggests the need for complete reorganization and coordination of conservation efforts for this species, paying particular attention to the long‐term preservation of the genetic diversity. Also identified is the only potentially suitable stock of F1 animals that should be used as source of future breeders.
      PubDate: 2014-08-02T01:08:27.428554-05:
      DOI: 10.1111/jai.12545
       
  • Status and management of lake sturgeon (Acipenser fulvescens Rafinesque,
           1817) in the upper St. Croix River and Namekagon River, Wisconsin, USA
    • Authors: J. Kampa; G. Hatzenbeler, M. Jennings
      Abstract: The upper St. Croix River and Namekagon River have been managed with a closed lake sturgeon (Acipenser fulvescens Rafinesque, 1817) fishing season since 1994. Lake Sturgeon abundance and distribution have not been assessed above the confluence of the two rivers since this regulation was established. We documented abundance, distribution and movement of the Lake Sturgeon in both rivers from their confluence upstream to the first dam on each river during 2008–2012. Captured with boat‐mounted direct current electrofishing and by hook and line, 136 sturgeon ranging from 37 cm to 140 cm total length were tagged. Annual electrofishing catch was only 6% of the catch during the 1960s on a 32 km reach of the Namekagon River. Size structure showed that recruitment was significantly higher during the 1960s in the Namekagon River. Lake Sturgeon movement between rivers was documented during both sampling periods with direct line movements of >80 km. While still depressed, the A. fulvescens population below the first dam upstream from the confluence of the Namekagon River and the upper St. Croix River is naturally recruiting and appears to have the potential to restore itself with a closed fishing season.
      PubDate: 2014-07-30T05:33:08.10332-05:0
      DOI: 10.1111/jai.12541
       
  • Salinity effects on Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus
           Mitchill, 1815) growth and osmoregulation
    • Authors: P. J. Allen; Z. A. Mitchell, R. J. DeVries, D. L. Aboagye, M. A. Ciaramella, S. W. Ramee, H. A. Stewart, R. B. Shartau
      Abstract: The Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus Mitchill, 1815) is an anadromous sturgeon species, yet little is known with regard to its osmoregulatory ability and habitat use at early life stages. In order to examine whether salinity poses a physiological challenge to juvenile Atlantic sturgeon near the sizes where they may begin to move into saline habitats, growth and osmoregulatory ability were tested. Juvenile Atlantic sturgeon (mean initial weight: 440 g) were acclimated to one of three salinity conditions (0, 10, or 33 ppt) representing the range of salinities they would be expected to encounter. Growth was measured over a 6‐month period, and osmoregulatory ability (i.e. blood plasma osmolality and ionic concentrations) was measured after 4 months. Mean weight and length increased in all treatments, but fish in 0 and 10 ppt grew more than fish in 33 ppt. Blood plasma osmolality was regulated at similar levels regardless of salinity. Therefore, juvenile Atlantic sturgeon have the physiological capability to move between salinity habitats, but grow faster in low salinities.
      PubDate: 2014-07-29T06:28:49.557538-05:
      DOI: 10.1111/jai.12542
       
  • Impact of live food on survival and growth of hatchery‐reared sea
           trout (Salmo trutta trutta L.) parr in the wild
    • Authors: R. Czerniawski; J. Domagala, T. Krepski, M. Pilecka‐Rapacz
      Abstract: Survival rates and growth parameters of hatchery‐reared sea trout (Salmo trutta trutta L.) fry were determined after stocking in the wild. The larvae were hatchery‐reared for 12 weeks in two groups: fry were fed either on live zooplankton and live chironomidae larvae (LFG), or fed a pellet diet (PFG). The survival rate and specific growth rates were higher in the LFG than in the PFG group. Most effective for hatchery‐reared fish intended for stocking was the natural, live feed. The mean number of chironomid larvae found in the stomachs of fish that were initially captured in the wild was significantly higher in the LFG than in the PFG group. The live diet supplied in the rearing period had a positive impact on the foraging skills of the sea trout fry and their survival in the wild after their release on 24 April 2010.
      PubDate: 2014-07-29T06:28:41.392399-05:
      DOI: 10.1111/jai.12503
       
  • Seasonal diet composition of juvenile and adult pallid sturgeon,
           Scaphirhynchus albus (Forbes & Richardson, 1905), in the channelized
           lower Missouri River
    • Authors: K. R. Winders; J. E. Dattilo, T. R. Huffmon, V. H. Travnichek
      Abstract: Although habitat alterations and reproductive success are the main contributors to declines of the pallid sturgeon, Scaphirhynchus albus (Forbes & Richardson, 1905) listed in 1990 as federally endangered, disrupted trophic links within diets of pallid sturgeon populations have been hypothesized as partial contributors. The objective of this study was to evaluate pallid sturgeon food habits within a 500 km reach of the lower channelized Missouri River using non‐lethal pulsed gastric lavage. Trotlines, gill nets, trammel nets, and benthic otter trawls were used to collect 284 pallid sturgeon, which ranged in fork length from 265 to 1047 mm. Stomach contents of pallid sturgeon included fish (Cyprinidae and Ictaluridae), aquatic insects, copepods, leeches, and mussels. Cyprinids were the most abundant prey item; ictalurids were also of high abundance. Otter trawl catch rates of ictalurids and cyprinids were not spatially correlated to the respective abundances in pallid sturgeon diets; however, the ratio of the average catch rate to the average number of fish per pallid sturgeon indicated preference for cyprinids (1.5 : 1), particularly Macrhybopsis species, relative to ictalurids (7 : 1). Our results support the need for management of native cyprinids, especially Macrhybopsis species, which have been in decline within the entire range of the pallid sturgeon. However, pallid sturgeon are also able to consume ictalurids, a species which has remained in high abundance in the lower Missouri River.
      PubDate: 2014-07-29T06:28:36.845458-05:
      DOI: 10.1111/jai.12540
       
  • First length–weight relationships of 11 fish species in the Aegean
           Sea
    • Authors: S. Yapici; P. K. Karachle, H. Filiz
      Abstract: Weight‐length relationships were established for eleven marine fish species caught in the SE Aegean Sea, Turkey. Additionally, a bibliographic review of such relationships for these species was conducted. Based on the results, the values of b parameter varied between 2.477 and 3.496, with one species having isometric growth, five negative and six positive allometric growth. Furthermore, for Aulopus filamentosus there exist no information in the literature, whilst for Callanthias ruber and Gnathophis mystax, there are no such information available from the Mediterranean.
      PubDate: 2014-07-28T06:03:56.7133-05:00
      DOI: 10.1111/jai.12459
       
  • Weight–length and length–length relationships for reef fish
           species from the Cape Verde Archipelago (tropical north‐eastern
           Atlantic)
    • Authors: M. T. Oliveira; M. N. Santos, R. Coelho, V. Monteiro, A. Martins, P. G. Lino
      Abstract: This study reports weight–length and length–length relationships for selected coastal reef fish species of the Cape Verde Archipelago (tropical north‐eastern Atlantic). Specimens were caught with different types of gear (long‐lines, hand‐lines, purse‐seines and traps) during commercial fishing activities and sampled during fish market operations. A total of 8328 individuals were sampled, representing 29 species from 14 Families. This study provides the first references on weight–length and length–length relationships for five and 23 fish species worldwide, for 10 and 24 species for the Eastern Atlantic and for 12 and 26 species for Cape Verde Archipelago, respectively. Additionally, it provides revised weight–length relationships for 11 species from Cape Verde waters.
      PubDate: 2014-07-10T02:49:11.807088-05:
      DOI: 10.1111/jai.12497
       
  • Spatiotemporal occurrence and feeding habits of tonguefish, Cynoglossus
           lighti Norman, 1925, larvae in Ariake Bay, Japan
    • Authors: G. Kume; K. Furumitsu, H. Nakata, T. Suzuki, M. Handa, A. Yamaguchi
      Abstract: Spatiotemporal occurrence and feeding habits of tonguefish (Cynoglossus lighti Norman, 1925) larvae were investigated in an offshore area (>5 m in depth) of the inner part of Ariake Bay, Japan. All specimens were symmetric, free‐swimming larvae. Although their seasonal abundance and distribution in the study site varied from year to year, spawning started in June and the larval abundance was high in August and September with a wide distribution in the inner part of the bay. Both present and previous study results strongly suggest that larvae may settle primarily in the estuary and near‐shore areas of Ariake Bay after their wide distribution in the offshore area of the bay during the free‐swimming stage. Larvae showed a clear feeding rhythm in which they fed on prey mainly during the daytime. Larvae fed exclusively on copepods, and identified prey were mostly Paracalanidae (mainly Parvocalanus crassirostris), Microsetella norvegica, and Oithona davisae. Pre‐metamorphosis larvae fed primarily on Paracalanidae and O. davisae, whereas O. davisae formed a smaller proportion of the early‐metamorphosis diet. In early metamorphoses, larvae fed preferentially on Paracalanidae and M. norvegica.
      PubDate: 2014-07-10T02:45:21.155113-05:
      DOI: 10.1111/jai.12498
       
  • Length–weight relationships for freshwater fish species from the
           Pantanal of the Negro River, Brazil
    • Authors: V. F. Batista‐Silva; D. Bailly, É. A. Gubiani, F. E. S. Costa, V. L. Lescano de Ameida, T. Liparelli
      Abstract: The present study describes the length‐weight relationships (LWRs) of 28 species captured in Santa Virgínia Bay, in the Pantanal of the Negro River, Mato Grosso do Sul State, Brazil, over 3 years (1999 to 2001). The study provides the first references on LWRs for thirteen of these species.
      PubDate: 2014-07-07T04:16:28.621174-05:
      DOI: 10.1111/jai.12495
       
  • Effect of artificial baits on the catch efficiency of monofilament gill
           nets
    • Authors: M. Dartay; E. Duman
      First page: 841
      Abstract: Greater success in catching fish with gill nets is possible if more the fish are attracted to the nets. Bait has been successfully used to lure fish into the gill nets. With the aim of increasing the catch efficiency of monofilament gill nets, a study was conducted between January 2009 and December 2010 to test the effect of artificial baits on the efficiency of 40, 50 and 55 mm monofilament gill nets in the Keban Dam Lake (Elazığ/Turkey). The catch rate of the baited nets was compared to similar nets without bait. Baited nets caught 482 fish (71.8% of the total, seven species). Non‐baited nets caught 189 fish (28% of the total, seven species). The majority of fish (238) were caught using baited gill nets with 40 mm mesh. The most commonly caught species was Capoeta trutta. The differences between the baited gill nets and non‐baited gill nets were statistically significant (P 
      PubDate: 2014-04-02T02:11:29.771069-05:
      DOI: 10.1111/jai.12434
       
  • Spatial and seasonal variations in fish assemblages of the Yangtze River
           estuary
    • Authors: Y. R. Shi; M. Chao, W. M. Quan, X. Q. Shen
      First page: 844
      Abstract: This study aimed to test the hypothesis that biotic influences play a role in determining estuarine fish assemblages. Thus the mechanisms that regulate the observed spatial niche segregation between fish species with morphological and ecological similarities within estuaries were investigated. Fishes were sampled seasonally at 30 stations along an entire salinity gradient of the Yangtze River estuary from spring 2010 to winter 2011, using bottom trawling (10 mm mesh size in the cod end). A total of 62 species belonging to 28 families were collected. Marine migrants (21) and estuarine species (19) dominated the assemblage and accounted for the highest abundances (marine migrants = 42.5%, estuarine species = 38.3%), with the marine migrants having the highest biomass (57.2%). Canonical correspondence analyses indicated that chlorophyll a, salinity, temperature, and geographic distance were the four main variables influencing the occurrence of fishes within the system. A stable fish assemblage in the upper zone during the wet season (spring and summer) was more obvious than in the dry season. The Pianka index showed a clear spatial segregation in four pairs of tonguesoles species (Cygonobius), and in most pairs of gobiids (Gobiidae), and a high degree of overlapping (>0.60) in only four pairs of gobiid species during the wet season. However, according to the results of the null model the observed segregating or pattern sharing was not caused by interspecific competition.
      PubDate: 2014-05-07T03:06:57.788885-05:
      DOI: 10.1111/jai.12448
       
  • Interspecific habitat associations of juvenile salmonids in Lake Ontario
           tributaries: implications for Atlantic salmon restoration
    • Authors: J. H. Johnson; M. A. Chalupnicki
      First page: 853
      Abstract: Diel variation in habitat use of subyearling Chinook salmon (Oncorhynchus tshawytscha), subyearling coho salmon (O. kisutch), yearling steelhead (O. mykiss), and yearling Atlantic salmon (Salmo salar) was examined during the spring in two tributaries of Lake Ontario. A total of 1318 habitat observations were made on juvenile salmonids including 367 on steelhead, 351 on Chinook salmon, 333 on Atlantic salmon, and 261 on coho salmon. Steelhead exhibited the most diel variation in habitat use and Chinook the least. Juvenile salmonids were generally associated with more cover and larger substrate during the day in both streams. Interspecific differences in habitat use in both streams occurred with Atlantic salmon (fast velocities) and coho salmon (pools) using the least similar habitat. Chinook salmon and Atlantic salmon used similar habitat in both streams. These findings should help guide future management actions specific to habitat protection and restoration of Atlantic salmon in Lake Ontario tributaries.
      PubDate: 2014-06-02T23:50:25.947034-05:
      DOI: 10.1111/jai.12456
       
  • Growth and reproduction of the non‐native icefish Neosalanx
           taihuensis Chen, 1956 (Salangidae) in a plateau lake, southwestern China
    • Authors: F.‐Y. Zhu; S.‐W. Ye, Z.‐J. Li, T.‐L. Zhang, J. Yuan, Z.‐Q. Guo, J.‐F. Tang, J.‐S. Liu
      First page: 862
      Abstract: Growth, reproduction and abundance traits of the invasive icefish Neosalanx taihuensis Chen, 1956 were investigated monthly from July 2009 to May 2011 in Lake Erhai on the Yunnan‐Guizhou Plateau, south‐western China, in order to explore the changes in life‐history traits after translocation. The results indicated that the icefish exhibited obvious plasticity in growth and reproduction traits. Growth of the fish in Lake Erhai was faster than that in native waters and in other translocated reservoirs. By fitting the von Bertalanffy growth model to the data, it was estimated that icefish obtain an asymptotic size of 96.12 mm, a K of 1.61, and a t0 of ‐0.26; the calculated overall growth performance index φ′ was 4.17. The strategy of reproduction changed from multiple‐ to single‐spawning. The spawning period was from October to December with the absolute and relative fecundities of 1250 ± 169 eggs per ind and 2557 ± 245 eggs per g, respectively. Plasticity in icefish growth and reproduction in Lake Erhai greatly facilitated its population establishment, making it one of the most abundant fish species. The icefish invasion in the lake may be one of the reasons for the decrease or extinction of native fish species populations, and some measures for the control of this invasive fish are suggested.
      PubDate: 2014-07-02T01:13:00.806782-05:
      DOI: 10.1111/jai.12475
       
  • Reproduction, growth and mortality of the exploited sillaginid, Sillago
           ciliata Cuvier, 1829
    • Authors: F. A. Ochwada‐Doyle; J. Stocks, L. Barnes, C. A. Gray
      First page: 870
      Abstract: The goal of this study was to examine the age and size composition, growth, reproductive biology and mortality of Sillago ciliata Cuvier, 1829 in one of the largest estuarine commercial fisheries in south‐eastern Australia. The study also aimed to present a qualitative comparison of latitudinal variations in some of these characteristics along the eastern Australian coastline. The sampled population contained fish aged up to 10 years with a maximum size of 39.2 cm fork length (LF), and was dominated by 1–5 year olds. Sexual divergence in both the age and size structure of the population was recorded. Female S. ciliata grew slightly faster and attained a greater maximum size (L∞ = 33.79 cm LF, k = 0.50 year−1 and t0 = −0.57 years) than males (L∞ = 29.73 cm LF, k = 0.49 year−1 and t0 = −0.67 years). Females also matured at a significantly larger size (19.13 cm) and older age (1.63 years) than males (size: 17.07 cm, age: 1.10 years). Reproductive activity was highest between September and March. There were no differences between males and females in terms of mortality rate; the estimated total population, natural and fishing mortality rates were Z = 0.64, M = 0.42 and F = 0.22, respectively. Although these mortality rates suggest that S. ciliata in the Clarence River are relatively resilient to current rates of exploitation, regular monitoring of their commercial and recreational catch as well as their population structure is recommended in order to maintain sustainable fisheries. Potential latitudinal shifts in the spawning period, age structure and growth of S. ciliata along eastern Australia were also revealed.
      PubDate: 2014-06-20T06:31:22.463756-05:
      DOI: 10.1111/jai.12478
       
  • Stock structure delineation using variation in otolith chemistry of
           snakehead, Channa punctata (Bloch, 1793), from three Indian rivers
    • Authors: K. Miyan; M. Afzal Khan, S. Khan
      First page: 881
      Abstract: Otolith chemistry was used to study the stock structure of Channa punctata collected from the River Ganga and its tributaries, the rivers Yamuna and Gomti. Whole sagittal otoliths were subjected to acid digestion to analyse the trace elements (Ca, Na, Mg, Sr, Mn, Ba, Fe and K) using ICP‐AES. Data were subjected to appropriate statistical treatments, such as univariate anova, ancova, manova and DFA in order to delineate the fish stock(s) accurately. Mean concentrations of Ca, Mg, Sr, Mn, Ba, Fe and K in the otoliths of the fish from selected sites of the different rivers were significantly (P  0.05). In classification statistics, 96% of individuals were correctly classified to their original groups. The scatter plot of DF‐I vs DF‐II depicted the presence of different stocks in the River Ganga and its selected tributaries. Variations in the microchemistry of the otoliths showed the presence of four C. punctata stocks in the three selected rivers.
      PubDate: 2014-06-30T07:18:16.427809-05:
      DOI: 10.1111/jai.12479
       
  • Effect of stocking strategy on distribution and recapture rate of common
           carp Cyprinus carpio L., in a large and shallow temperate lake:
           implications for recreational put‐and‐take fisheries
           management
    • Authors: A. Specziár; B. Turcsányi
      First page: 887
      Abstract: It is hypothesized that the stocking procedure influences survival, growth and distribution of introduced fishes; however, there is still limited information on the effect of various stocking strategies on recaptures in natural freshwaters. The present study aim was to investigate how the rate and distribution of anglers' catches of common carp (Cyprinus carpio) vary with the stocking season (spring, summer and autumn), lake area, method (shore and offshore releases), and fish size (≤500 and >500 g) in the large and shallow Lake Balaton, Hungary. In 2010, 4500 two‐summer‐old individually‐tagged common carp were stocked to test 36 release set‐ups (three seasons × three lake areas × two methods × two size groups). Anglers reported the date, location and fish size (standard length and weight) on 787 recaptures within 2 years after the release. Recapture rate was highest in summer and lowest in autumn stockings, but was not affected by the stocking area, method or fish size. Regarding space, the widest dispersals were in recaptures in autumn and in the centre of the lake, but fish movement was not influenced by the stocking method or fish size. In conclusion, in summer the stocking quotas should be evenly distributed along the entire shoreline; early spring stockings may be optimized for transport costs and concentrated by each lake basin. Late autumn stockings should be avoided, and the capacity of effective wintering ponds should be developed. This study also provides a good framework for testing fisheries management alternatives in other intensively fished habitats.
      PubDate: 2014-07-01T03:37:03.615582-05:
      DOI: 10.1111/jai.12488
       
  • Changes in fatty acid profiles of three tissue types in channel catfish
           Ictalurus punctatus (Rafinesque, 1818) transferred from river to pond
           environments
    • Authors: M. P. Young; G. W. Whitledge, J. T. Trushenski
      First page: 895
      Abstract: Little information is available regarding the time scale over which tissue fatty acid (FA) profiles change when fish transition between prey resources with different FA profiles, specifically when fish move from a main river channel to a floodplain habitat. The objective of this study was to evaluate changes in the FA composition of muscle, liver, and adipose fin tissues of channel catfish Ictalurus punctatus transferred from the Kaskaskia River, Illinois to earthen ponds at the Center for Fisheries, Aquaculture, and Aquatic Sciences Pond Facility, Makanda, Illinois, mimicking migration from river to floodplain habitat. Over time, n‐3 and C18 polyunsaturated FA (C18 PUFA) decreased in all tissues, whereas monounsaturated fatty acids (MUFA) increased with pond residence time. Liver profiles changed more rapidly than the muscle or adipose fin profiles (significant change in
      PubDate: 2014-07-07T02:28:37.776882-05:
      DOI: 10.1111/jai.12485
       
  • Occurrence of Apristurus species in the Galicia Bank Seamount (NE
           Atlantic)
    • Authors: C. Rodríguez‐Cabello; M. Pérez, R. Bañon
      First page: 906
      Abstract: The aim of this study was to identify some of the Apristurus species by combining morphometric and genetic tools. Several specimens of the genus Apristurus were caught on the Galicia Bank Seamount (NE Atlantic), between 1460 and 1809 m depths, during a multidisciplinary survey carried out in 2011 within the framework of the INDEMARES Project. Morphometric and genetic analyses were conducted to aid the identification of the specimens collected. A total of 20 specimens were identified, of which 18 corresponded to Apristurus aphyodes (Nakaya and Stehmann, ), one to A. profundorum (Goode and Bean, ) and one to A. melanoasper Iglesias, Nakaya & Stehmann, . Genetic results based on the mtDNA COI sequences (682–690 bp fragment of the COI gene) support the identification of A. profundorum and A. melanoasper, with a bootstrap of 99 and 96%, respectively. The identification of A. aphyodes was also performed using a 499 bp fragment of the 16S mitochondrial gene. These are the first records of the Apristurus species from Galician waters, which extends their known area of distribution and provides more information on different biological and ecological aspects of this complex taxonomic group.
      PubDate: 2014-07-07T02:24:25.296055-05:
      DOI: 10.1111/jai.12480
       
  • Effect of the coexistence on the replication of striped jack nervous
           necrosis virus (SJNNV) and red‐spotted grouper nervous necrosis
           virus (RGNNV) using an in vitro approach
    • Authors: B. Lopez‐Jimena; E. Garcia‐Rosado, C. Infante, D. Castro, J. J. Borrego, M. Carmen Alonso
      First page: 916
      Abstract: Viral nervous necrosis virus (VNNV) is the aetiological agent of viral nervous necrosis (VNN), a widespread disease affecting different marine and freshwater fish species. Striped jack nervous necrosis virus (SJNNV) and red‐spotted grouper nervous necrosis virus (RGNNV) are the only genotypes of the Betanodavirus genus recorded in the Iberian Peninsula to date, but a high percentage of wild specimens simultaneously carrying both genotypes has been recently reported. The coexistence of the two viruses may affect the course of both viral infections. In the present study, viral genome quantification by two absolute real‐time PCR protocols has been performed to characterise the effect of the RGNNV‐SJNNV coexistence (coinfection and superinfection) on the replication of each genotype in E‐11 cells. This is the first study showing the effect of the coexistence on the viral replication of two genotypes within the Betanodavirus genus. The results obtained in vitro showed the partial inhibition of SJNNV replication by the coexistence with RGNNV, whereas RGNNV replication was favoured in coinfection or superinfection with SJNNV.
      PubDate: 2014-06-30T07:26:26.189436-05:
      DOI: 10.1111/jai.12473
       
  • Histopathology and helminth parasites of African catfish Clarias
           gariepinus (Burchell, 1822) in relation to heavy metal pollution in a
           subtropical river system
    • Authors: M. Barson; N. Mabika, R. G. Cooper, T. Nhiwatiwa
      First page: 923
      Abstract: In a study aimed to determine the histopathology, component parasite communities and level of selected heavy metals, African catfish Clarias gariepinus from three rivers in Zimbabwe (Gwebi, Manyame and Mukuvisi) were analysed for heavy metals (Cd, Cr, Cu, Fe, Ni, Pb, Zn) in the gills, liver, kidney and muscles. The histopathology of these tissues was assessed by microscopic examination of stained thin sections. Metazoan parasite diversity and species composition in fish along different sites of the rivers were determined and compared. Levels of Cd, Fe, Pb and Zn were lowest in the Gwebi, Cr and Cu in the Manyame, and Ni in the Mukuvisi River. There were significant differences (P 
      PubDate: 2014-06-30T07:18:21.865783-05:
      DOI: 10.1111/jai.12464
       
  • Geographic variation of body morphology of the Atlantic bluefin tuna,
           (Thunnus thynnus, Linnaeus, 1758)
    • Authors: P. Addis; M. Secci, M. Pischedda, U. Laconcha, H. Arrizabalaga
      First page: 930
      Abstract: Geometric morphometric methods were used to explore body shape morphology in 260 Atlantic bluefin tuna, Thunnus thynnus, collected in Sardinia (Western Mediterranean) during the breeding phase and in the Bay of Biscay (North Eastern Atlantic) during the feeding phase. The shape of each specimen was captured by high resolution digital images and recording the 2‐D coordinates of seven morphological landmarks. A general procruste analysis (GPA) was applied in order to eliminate any morphological variations resulting from size, position or orientation of specimens. A thin plate‐spline (TPS) method was then used to provide a graphical representation of the shape conformation between two sets of data. Results of the regression model between the direct and indirect measurements accounted for a R2 = 0.98. The Principal Components Analysis shows differences linked to the two sampling areas, accounting for 37% and 19.97% of the body shape variation in the first (PC1) and second (PC2) principal component, respectively. Specifically, the deformation grid projection highlights the major differences regarding the anterior‐ventral part of the body (landmark 5‐6‐7). These differences might not necessarily be linked to an actual population substructure. Instead, it was hypothesized that such body shape differences were due to the diverse life phases during which specimens were collected, since the reproductive specimens show a ‘pot‐bellied’ shape, which was larger than for the feeding specimens that showed a ‘slimmer’ shape. Analyses of likely sexual dimorphism conducted on Sardinian specimens did not reveal any significant differences; whereas body shape differences related to the pre‐ and post‐reproductive sizes were detected.
      PubDate: 2014-06-09T05:24:52.777162-05:
      DOI: 10.1111/jai.12453
       
  • Helminth communities of the Turkish endemic fish, Pseudophoxinus crassus
           (Ladiges, 1960): four helminth parasites for a new host record
    • Authors: A. Aydogdu; F. Erk'akan, N. Keskin, D. Innal, I. Aslan
      First page: 937
      Abstract: Tuz Gölü (Salt Lake) Basin is one of the largest hypersaline lakes in the world and of extremely high biological importance owing to its high diversity and high level of endemism. It is hypothesized that the basin environment and the endemism of Pseudophoxinus crassus – a species of ray‐finned fish in the Cyprinidae family and found only in Turkey – might contribute to the host‐specific parasite characters. A total of 92 P. crassus specimens were collected by electrofishing between spring 2009 and autumn 2010 from the İncesu Stream in Konya Province, Turkey. By the end of the study period, four parasitic helminth species (Gyrodactylus latus, Asymphylodora imitans, Bothriocephalus acheilognathi and Pomphorhynchus laevis) were recorded. All had been reported previously from other hosts (non‐host specific). Among these parasites G. latus and A. imitans are new records for the helminth fauna of Turkey. Prevalence and infestation intensity, length classes, and sex compositions of infested populations, as well as the seasonality of infestation were obtained and the results compared with other studies.
      PubDate: 2014-04-21T07:20:15.615501-05:
      DOI: 10.1111/jai.12442
       
  • Genetic diversity and population structure in the mtDNA control region of
           Liza haematocheilus (Temminck & Schlegel, 1845)
    • Authors: T. Gao; Y. Li, C. Chen, N. Song, B. Yan
      First page: 941
      Abstract: The redlip mullet (Liza haematocheilus) is a commercial marine species widespread in the Northwestern Pacific. The genetic diversity and population structure of the redlip mullet collected from 2007 to 2010 along Chinese and Japanese coastal regions, were investigated by mitochondrial DNA. A total of 82 L. haematocheilus individuals were collected from five locations and 41 haplotypes were obtained. A pattern of distribution of genetic variability with high level of haplotype diversity (0.9642 ± 0.0104) and moderate nucleotide diversity (0.0162 ± 0.0085) was detected. The minimum spanning tree constructed with 41 haplotypes showed three divergent clades, corresponding to those defined in the NJ tree. Analyses of molecular variance and the population statistic FST also revealed significant genetic structures among populations of L. haematocheilus. The demographic history of L. haematocheilus was examined using neutrality tests and mismatch distribution analysis, which indicated a Pleistocene epoch population expansion. Comparisons of the Hakodate and Qingdao populations in different years demonstrated that marginal but significant (P  0.05) in the Hakodate populations. Knowledge of their genetic diversity and genetic structure is crucial to establishing appropriate fishery management for the species.
      PubDate: 2014-04-03T04:22:18.220955-05:
      DOI: 10.1111/jai.12409
       
  • Age and growth characteristics of Schizopygopsis younghusbandi Regan, 1905
           in the Yarlung Tsangpo River in Tibet, China
    • Authors: Y.‐J. Duan; C.‐X. Xie, X.‐J. Zhou, B.‐S. Ma, B. Huo
      First page: 948
      Abstract: To better understand the biology of Schizopygopsis younghusbandi Regan, 1905 and its relationship with management considerations, this study describes the relationships between otolith size and fish length and age, verifies annual periodicity of otolith annulus formation, and estimates the S. younghusbandi growth parameters. These age and growth characteristics were studied using 694 specimens collected from August 2008 to August 2009. Otoliths grew asymmetrically throughout the range of standard length (SL) studied, showing a clear pattern of alternating translucent and opaque bands. Marginal increment ration (MIR) analysis of specimens up to 6 years of age indicated that one opaque band and one translucent band were laid down each year. Maximum observed age was 17 years, corresponding to a female of 35.8 cm SL and 589.1 g body weight (BW). The SL‐BW relationship was described as BW = 1.122 × 10−5 SL3.030 for sexes combined. The von Bertalanffy growth function was used to model back‐calculated lengths as Lt = 338.4 (1−e−0.233 (t + 0.403)) for males, and Lt = 433.9 (1−e−0.194 (t + 0.397)) for females. Growth performance of S. younghusbandi was relatively higher than those of other Schizothoracinaes inhabiting the same river.
      PubDate: 2014-04-21T07:21:00.779511-05:
      DOI: 10.1111/jai.12439
       
  • Diet shift response in round goby, Neogobius melanostomus, based on size,
           sex, depth, and habitat in the western basin of Lake Erie
    • Authors: H. A. Thompson; T. P. Simon
      First page: 955
      Abstract: This study examines the diet of the round goby (Neogobius melanostomus) in the western basin of Lake Erie. As an invasive benthic feeder, the round goby has the potential to affect smallmouth bass and other native species. Round goby (n = 100) were collected during summer 2011 and stomach contents were examined to determine diet patterns and possible ontogenetic diet shifts. Individual round goby were grouped by sex, size (small 
      PubDate: 2014-04-22T23:50:38.701311-05:
      DOI: 10.1111/jai.12441
       
  • An evaluation of multiple‐pass seining to monitor blackstripe
           topminnow Fundulus notatus (Rafinesque, 1820) in the Sydenham River
           (Ontario, Canada)
    • Authors: S. M. Reid; S. Hogg
      First page: 962
      Abstract: Multiple‐pass (i.e. removal) sampling and mark‐recapture experiments were undertaken in the Sydenham River (Ontario, Canada) to assess the effectiveness of seining to detect and estimate the local abundance of blackstripe topminnow, Fundulus notatus (Rafinesque, 1820) as well as to compare catch characteristics from closed and open (with and without block nets) sample units. Probability of species detection using three‐pass seining was estimated to be 0.58 in closed units, and 0.51 in open units. To be 95% confident of occupancy status, a minimum of five repeat surveys is required. A decline in catch occurred in only half of the sample units, population size estimates were often imprecise, and attempts to generate mark‐recapture population estimates were unsuccessful. Mean capture probabilities were 0.48 in closed units and 0.65 in open units, when depletion occurred. For blackstripe topminnow and other fishes encountered, there were no significant differences between closed and open units in the frequency of depletion or capture probability. Compared to single‐pass surveys, monitoring programs that employ three seine hauls are more likely to detect the presence of the blackstripe topminnow and any decline in local abundance.
      PubDate: 2014-04-04T05:28:59.465597-05:
      DOI: 10.1111/jai.12447
       
  • Diet of marine fish larvae and juveniles that use rocky intertidal pools
           at the Portuguese coast
    • Authors: M. Dias; A. Silva, H. N. Cabral, C. Vinagre
      First page: 970
      Abstract: The use of tidal pools during early ontogeny is likely to enhance growth, condition and survival chances of the transient marine fish larvae and juveniles that use them. However, the diet of such individuals within tidal pools is poorly known; this knowledge is important to understand why such high numbers of individuals use these environments in spring and summer on the Portuguese coast. Transient marine fishes were sampled monthly over a two‐year period in four tidal pools of a rocky reef on the west Portuguese coast. The diet composition in the tidal pools of the most abundant marine fish larvae/juveniles, Diplodus sargus and Atherina spp., were investigated. Stomach and gut contents of 483 individuals (354 D. sargus ranging in total length from 9 to 87 mm and 134 Atherina spp. ranging in total length from 10 to 31 mm) were analyzed and dietary indices estimated for the different developmental stages. The diet of D. sargus composed mainly harpacticoid copepods, chironomid larvae, ostracods, chironomid adults and amphipods; whereas the diet of Atherina spp. was mainly harpacticoid copepods, ostracods and gastropods. Along the ontogenetic development, the proportions and diversity of food items in the D. sargus diet varied. Importance of the harpacticoid copepods decreased with increasing fish size, while that of amphipods and isopods increased. Larvae and juvenile D. sargus and Atherina spp. found in rocky reef tidal pools are opportunistic consumers of a wide range of prey and thus take advantage of the high prey availability in these habitats.
      PubDate: 2014-05-05T05:32:32.182181-05:
      DOI: 10.1111/jai.12450
       
  • Bio‐economic analysis of the Mar Menor (Murcia, SE Spain)
           small‐scale lagoon fishery
    • Authors: F. Maynou; P. Martínez‐Baños, M. Demestre, R. Franquesa
      First page: 978
      Abstract: An integrated fisheries management tool based on a bio‐economic model was applied to the demersal fishery in the Mar Menor coastal lagoon in SE Spain, with the objective of exploring solutions to ensure the sustainability of this activity. The hypothesis is that excess harvesting in recent years by fishers trying to offset growing production costs has led to the inefficient use of lagoon fishery resources. The authors established the basic bio‐economic conditions of the fishery in 2012 by means of field sampling and personal interviews with producers, and analyzed the response of several biological and economic indicators (target species biomass and yield, fleet profits) to a management scenario based on limiting the fishing season of one of the main types of fishing gear (fish traps, locally known as ‘paranzas’). Results show that a reduction in fishing mortality of two overexploited species (Sparus aurata and Lithognathus mormyrus) will help recover the biomass of these stocks by more than 40% as well as increase the economic value of the fishery, with profits increasing by 17% over a 4‐year period.
      PubDate: 2014-06-09T05:47:44.083141-05:
      DOI: 10.1111/jai.12460
       
  • Enumeration of gut associated extracellular enzyme‐producing yeasts
           in some freshwater fishes
    • Authors: S. Banerjee; K. Ghosh
      First page: 986
      Abstract: Extracellular enzyme‐producing yeasts might be involved in the supplementation of enzymes within the gastrointestinal tract of fish. The present study was intended to detect yeasts in the intestine of three Indian major carps (Labeo rohita, Catla catla, Cirrhinus mrigala), three exotic carps (Hypophthalmichthys molitrix, Ctenopharyngodon idella, Cyprinus carpio), as well as Nile tilapia (Oreochromis niloticus), and to identify the most promising extracellular enzyme‐producing (e.g. amylase, protease, lipase, cellulase, xylanase and phytase) yeast strains by 18S rDNA sequence analysis. Selected for qualitative enzyme assay were 121 yeast strains, from which 28 were further studied for quantitative enzyme assay. The strain CMH6A isolated from C. mrigala exhibited the best extracellular enzyme activities except for amylase and cellulase. The strain ONF19B isolated from O. niloticus was noted as the best extracellular enzyme producer among the strains that produced all of the extracellular enzymes studied. Sequencing of the 18S rDNA fragment followed by nucleotide blast in the National Centre for Biotechnology Information (NCBI) GenBank revealed that strains CMH6A and ONF19B were similar to Pichia kudriavzevii (Accession no. KF479403) and Candida rugosa (Accession no. KF479404), respectively. The test of antagonism (in vitro) revealed that the isolated yeasts could not affect the growth of the autochthonous gut bacteria. This might indicate likely co‐existence of autochthonous yeasts and bacteria in the fish gut. Further research is necessary to explore the possibilities of utilizing the extracellular enzyme‐producing yeasts detected in the present study for commercial aquaculture.
      PubDate: 2014-06-02T23:37:42.939375-05:
      DOI: 10.1111/jai.12457
       
  • Influence of Tribulus terrestris extract on the survival and
           histopathology of Oreochromis mossambicus (Peters, 1852) fry before and
           after Streptococcus iniae infection
    • Authors: S. Yilmaz; S. Ergün, H. Kaya, M. Gürkan
      First page: 994
      Abstract: The aim of this study was to determine the effects of Tribulus terrestris extract (TT) on growth performance, disease resistance and histopathological changes in intestine and liver tissues of Oreochromis mossambicus (Peters, 1852) first‐feeding fry before and after exposure to Streptococcus iniae. Five isonitrogenous and isocaloric diets were formulated to contain 0 (control), 200, 400, 600, and 800 mg kg−1 TT. After feeding for 45 days, fish were infected with S. iniae and mortalities recorded. Final weight, weight gain and SGR of tilapia fry fed the 400 mg kg−1 TT diet were significantly greater than that of control diet. In the challenge experiment, the best survival rate was obtained with 400 mg kg−1 TT supplementation. Infection by S. iniae appeared to have a negative effect on histopathological findings and outcome than did TT‐800 used alone. However, administration of TT (200 or 400 mg extract kg−1) resulted in overall improvement in the intestine and liver histopathology, emphasizing the protective potential of TT. The present study suggests the protective potential of TT in alleviating intestinal and hepatic damage that can occur after a S. iniae infection. It was concluded that 400 mg kg−1 TT can enhance growth and disease resistance during first–feeding of O. mossambicus fry. This suggests that TT may be an alternative to antibiotics in controlling streptococcal disease in tilapia culture.
      PubDate: 2014-06-09T05:25:28.800465-05:
      DOI: 10.1111/jai.12458
       
  • Response of splenic melanomacrophage centers of Oreochromis niloticus
           (Linnaeus, 1758) to inflammatory stimuli by BCG and foreign bodies
    • Authors: W. G. Manrique; G. Silva Claudiano, T. R. Petrillo, M. Pardi Castro, M. A. Pereira Figueiredo, M. A. Andrade Belo, J. R. Engracia Moraes, F. Ruas Moraes
      First page: 1001
      Abstract: The study objective was to make histological, histochemical and morphometric evaluations on the splenic Melanomacrophage centers (MMCs) of tilapias, Oreochromis niloticus (Linnaeus, 1758), that were subjected to chronic inflammation stimuli by implantation (IMP) of a glass coverslip in the subcutaneous tissue and through inoculation of the bacillus Calmette‐Guerin (BCG). Randomly distributed in four groups were 150 tilapias: IMP (n = 45); IMP+BCG (n = 45); BCG (n = 45); and control (n = 15). Nine fish per treatment and three control fish were sampled on days 3, 7, 14, 21 and 33. The results demonstrated that increased numbers and areas of these structures were related to the type of stimulus, and that these were greater for the specific response. The principal pigment component identified was hemosiderin. Results suggest that the intensity of the MMC response in O. niloticus depended on the type of inflammatory stimulus used, and that it was greater in fish inoculated with BCG, which induced a granulomatous inflammation when compared to the foreign body inflammatory response induced by the glass coverslips.
      PubDate: 2014-04-09T05:39:04.524854-05:
      DOI: 10.1111/jai.12445
       
  • Where are the little ones: distribution and abundance of the threatened
           serranid Epinephelus daemelii (Günther, 1876) in intertidal habitats
           in New South Wales, Australia
    • Authors: D. Harasti; C. Gallen, H. Malcolm, P. Tegart, B. Hughes
      First page: 1007
      Abstract: A survey of intertidal habitats, including coastal rock pools, was undertaken across New South Wales (NSW), Australia, February to May 2012, to test the hypothesis that the distribution and abundance of threatened juvenile black cod Epinephelus daemelii (Günther, 1876) does not differ across marine bioregions. An assessment was also provided on their habitat use and site fidelity. Various methods were trialled to determine the best method for detecting juvenile E. daemelii, with the most suitable method being the deployment of small baited underwater high definition video cameras for a period of 30 min. Using these baited video cameras, sampling occurred across four bioregions in NSW, covering approximately 800 km of coastline. Within each bioregion, a minimum of nine locations was selected, and at each location a minimum of six intertidal habitats was surveyed for the presence of E. daemelii. Of 412 sites surveyed, a total of 20 juveniles (mean size = 16.7 cm ± 1.1 cm SE) were found in intertidal habitats along approx. 420 km of coastline. The smallest juvenile was LT 3 cm and the largest fish was stereo measured at LT 26.5 cm. E. daemelii were found to tolerate a large range of water quality parameters, particularly temperature (mean 21.7°C ± 0.7 SE, min = 16.8°C and max = 31.2°C) and dissolved oxygen (mean 11.2 mg L−1 ± 1.3 SE, min = 5.7 mg L−1 and max = 19.2 mg L−1). E. daemelii were found in habitats dominated by boulders and overhangs, indicating a preference for structural features that provide solid cover. No E. daemelii were recorded at sites that had algae as the dominant habitat type. Juvenile E. daemelii were found to display site fidelity to rock pool habitats, with two individuals recorded as remaining at their same sites for a period of 471 days, even though the rock pools were open to the ocean at high tides. This study indicates that the abundance of juvenile E. daemelii is low, especially north of Port Stephens where adults are most abundant. Use of the small baited video cameras proved to be a successful sampling method to confirm that juvenile E. daemelii utilise rock pool and shallow reef intertidal habitats in the early stages of their life cycle.
      PubDate: 2014-04-04T05:28:57.368216-05:
      DOI: 10.1111/jai.12446
       
  • Gillnet selectivity for freshwater fish species in three lentic systems of
           Greece
    • Authors: O. Petriki; K. Erzini, D. K. Moutopoulos, D. C. Bobori
      First page: 1016
      Abstract: Gillnet size selectivity was studied for freshwater fish species, based on experimental fishing trials carried out with multimesh gillnets in lentic freshwater systems in Northern Greece. Selectivity estimates were based on a large range of mesh sizes, i.e. more than 10 different mesh sizes ranging from 8 to 90 mm bar length. Results showed that the model, in which both mean and standard deviation of the curve were defined as a linear function of the mesh size, revealed the best fit. For seven (i.e. Αlburnus sp. Volvi, Aspius aspius, Carassius gibelio, Lepomis gibbosus, Pachychilon macedonicum, Squalius prespensis and Vimba melanops) of the 11 studied species and the hybrid (Alburnus belvica × Rutilus prespensis), gillnet selectivity parameters were estimated for the first time, contributing to the evaluation of gillnet fisheries' impacts on fish species populations and consequently to fisheries management and species conservation.
      PubDate: 2014-06-30T07:03:30.279211-05:
      DOI: 10.1111/jai.12476
       
  • New record of the mesoparasitic copepod Pennella filosa (L., 1758) on
           striped marlin Kajikia audax, (Collette, 2006) from Cabo San Lucas, Baja
           California Sur, Mexico
    • Authors: S. Hernández‐Trujillo; R. Funes‐Rodríguez, R. González‐Armas, S. Ortega‐García
      First page: 1028
      PubDate: 2014-05-06T06:52:46.036888-05:
      DOI: 10.1111/jai.12349
       
  • Gene pool and population structure in larval Herklotsichthys
           quadrimaculatus (Rüppell, 1837)
    • Authors: R. C. Thomas; P. D. Beldia, W. L. Campos, M. D. Santos
      First page: 1031
      PubDate: 2014-04-05T00:40:22.023518-05:
      DOI: 10.1111/jai.12438
       
  • First record of the red‐spotted wrasse Lappanella fasciata (Cocco,
           1833) (Labridae) in the Aegean Sea
    • Authors: A. C. Keskin; H. Dereli, E. Irmak
      First page: 1035
      PubDate: 2014-06-20T06:30:49.186987-05:
      DOI: 10.1111/jai.12463
       
  • Record of a newly introduced fish, red‐bellied pacu Piaractus
           brachypomus (Cuvier, 1818) (Characiformes, Serrasalmidae), in a tropical
           wetland system, India
    • Authors: K. Roshni; C. R. Renjithkumar, B. M. Kurup
      First page: 1037
      PubDate: 2014-06-20T06:25:46.848232-05:
      DOI: 10.1111/jai.12462
       
  • First record of the Indian Ocean anchovy Stolephorus insularis Hardenberg,
           1933 from the northeastern Mediterranean coast of Turkey
    • Authors: C. Dalyan; E. Yemişken, D. Erguden, C. Turan, L. Eryilmaz
      First page: 1039
      PubDate: 2014-06-30T07:18:23.67335-05:0
      DOI: 10.1111/jai.12467
       
  • Invasion characteristics of Pterygoplichthys ambrosettii (Holmberg, 1893)
           in the lower Paranapanema River, Brazil
    • Authors: D. A. Z. Garcia; F. S. Almeida, Â. T. Silva e Souza, J. R. Britton, M. L. Orsi
      First page: 1041
      PubDate: 2014-06-23T08:39:28.718207-05:
      DOI: 10.1111/jai.12468
       
  • First record of the redbelly tilapia, (Tilapia zillii Gervais, 1848), in
           Iran
    • Authors: R. Roozbhfar; M. Dehestani‐Esfandabadi, S. Roozbehfar
      First page: 1045
      PubDate: 2014-06-17T01:47:40.234531-05:
      DOI: 10.1111/jai.12469
       
  • Fistularia commersonii Rüppell, 1838 in the Mediterranean Sea:
           filling the Libyan gap
    • Authors: H. Elbarassi; A. E. Bashir, E. Azzurro
      First page: 1047
      PubDate: 2014-06-23T08:40:15.674341-05:
      DOI: 10.1111/jai.12470
       
  • The silver‐cheeked toadfish Lagocephalus sceleratus (Gmelin, 1789)
           reaches Italian waters
    • Authors: E. Azzurro; L. Castriota, M. Falautano, F. Giardina, F. Andaloro
      First page: 1050
      PubDate: 2014-06-24T09:52:22.716653-05:
      DOI: 10.1111/jai.12471
       
  • First record of Chrysiptera cyanea (Quoy and Gaimard, 1825) (Perciformes:
           Pomacentridae) in the Mediterranean Sea
    • Authors: L. Lipej; B. Mavrič, J. Dulčić
      First page: 1053
      PubDate: 2014-06-30T07:18:25.889643-05:
      DOI: 10.1111/jai.12472
       
  • Development and characterization of eleven microsatellite markers for an
           endangered cavefish (Triplophysa rosa Chen and Yang, 2005) using 454
           sequencing
    • Authors: J. Zhao; K. Zhao, Z. Peng
      First page: 1056
      Abstract: Triplophysa rosa is an endangered cave‐dwelling and endemic fish species found only in Chongqing, southwestern China. The genetic data available for this species is very limited. Polymorphic microsatellites were identified in the genome of T. rosa using 454 sequencing. Of the 145 loci screened, 106 were amplified successfully and 11 showed polymorphic patterns. The number of alleles ranged from 2 to 6, and the observed and expected heterozygosity varied from 0.061 to 0.543 (mean = 0.349) and from 0.248 to 0.789 (mean = 0.551), respectively. The polymorphic information content (PIC) ranged from 0.215 to 0.744 (mean = 0.486), indicating moderate levels of polymorphism. In addition, cross‐species amplification was tested for the 106 loci in Triplophysa moquensis, which showed a high level of transferability (76.4%), implying that the microsatellite markers developed here could be used effectively for other closely related species.
      PubDate: 2014-07-28T06:04:20.474612-05:
      DOI: 10.1111/jai.12474
       
  • Occurrence of the boarfish, Capros aper (Linneaus, 1758) in Edremit Bay,
           northern Aegean Sea (Osteichtyes: Caproidae)
    • Authors: Z. Erdogan; H. Torcu Koc, A. Bektas, C. Sarıgöl, T. Özbay
      First page: 1059
      PubDate: 2014-07-14T01:27:20.242714-05:
      DOI: 10.1111/jai.12500
       
  • Occurrence of the Kessler's gudgeon Romanogobio kesslerii (Dybowski, 1862)
           (Cyprinidae) in the Upper Vistula River (Poland)
    • Authors: M. Nowak; A. Klaczak, P. Szczerbik, J. Mendel, W. Popek
      First page: 1062
      PubDate: 2014-07-14T01:54:00.879861-05:
      DOI: 10.1111/jai.12501
       
  • Application of mesohabitat fish use information to identify guilds for
           lotic systems
    • Authors: M. A. Pegg; A. T. Behmer, P. Parasaweicz, J. N. Rogers
      First page: 1065
      PubDate: 2014-07-14T01:27:22.888402-05:
      DOI: 10.1111/jai.12502
       
  • Length–weight relationships of six freshwater cyprinid fishes of
           Iran
    • Authors: H. Nowferesti; S. Asgardun, P. Zare
      First page: 1069
      Abstract: Length–weight relationships were estimated for six cyprinid species of Iran. One of these species is endemic to Iran and the L–W parameters for three of the species are given for the first time.
      PubDate: 2014-06-14T02:31:44.38821-05:0
      DOI: 10.1111/jai.12373
       
  • Length–weight relationships of four fish species caught in the
           Northern Persian Gulf (Horomzgan waters, Iran)
    • Authors: H. Raeisi; M. Daliri, A. Hosseini, E. Kamrani, G. H. Moradinasab, M. Aghajanpour, M. Moein, M. Naderi
      First page: 1071
      Abstract: Length–weight relationships (LWRs) for four little‐known fish species collected in the northern Persian Gulf (south of Iran) are presented, namely, Leiognathus lineolatus, Grammoplites suppositus, Eupleurogrammus muticus and Acanthocepola abbreviate. Thus far, these are the first LWRs for these species in the international scientific literature.
      PubDate: 2014-05-30T07:10:54.939043-05:
      DOI: 10.1111/jai.12407
       
  • Length–weight relationships for 37 freshwater fish species of Iran
    • Authors: H. R. Esmaeili; A. Gholamifard, S. Vatandoust, G. Sayyadzadeh, R. Zare, S. Babaei
      First page: 1073
      Abstract: Length–weight parameters were estimated for 37 freshwater fish species of Iran belonging to seven families. Significant length–weight relationships with high correlation coefficients were found for all species.
      PubDate: 2014-04-03T04:41:37.798744-05:
      DOI: 10.1111/jai.12433
       
  • Length–weight relationships of 33 selected fish species from the
           Cauca River Basin, trans‐Andean region, Colombia
    • Authors: A. Zuluaga‐Gómez; T. Giarrizzo, M. Andrade, A. Arango‐Rojas
      First page: 1077
      Abstract: This study provides length–weight relationships (LWRs) for 33 fish species sampled with several types of fishing gear in six expeditions between 2010 and 2011, during the dry and wet seasons in the middle and lower Cauca River Basin, Northern Colombia. The report represents the first reference on LWRs for 28 species and also provides the new maximum size for 15 species.
      PubDate: 2014-04-03T04:52:47.198609-05:
      DOI: 10.1111/jai.12435
       
  • Length‐weight relationships of dominant fish species from
           Caxiuanã National Forest, Eastern Amazon, Brazil
    • Authors: T. M. S. Freitas; B. S. Prudente, N. F. Fontoura, L. F. A. Montag
      First page: 1081
      Abstract: The present work presents parameters of the length–weight relationships (LWR) for 12 species of freshwater fish from rivers within the Caxiuanã National Forest, Eastern Amazon. Data coverage include the main taxonomic groups in the sampling area: Characiformes: Acestrorhynchidae, Anostomidae, Curimaridae, Erythrinidae, Hemiodontidae; Siluriformes: Auchenipteridae; Perciformes: Sciaenidae. LWR parameters are estimated for the first time for five species: Leporinus affinis, Bryconops melanurus, Pygopristis denticulata, Serrasalmus gouldingi and Triportheus albus. Relative growth patterns were evenly distributed among species, one‐third showing negative allometry (b  3; n = 4).
      PubDate: 2014-04-02T02:11:33.764622-05:
      DOI: 10.1111/jai.12436
       
  • Length–weight relationships and growth parameters of two endemic
           fish species (Floridichthys polyommus Hubbs, 1936 and Fundulus persimilis
           Miller, 1955) from the Yucatan Peninsula, Mexico
    • Authors: M. Badillo‐Alemán; J. L. Bonilla‐Gómez, J. Tzeek‐Tuz, A. Gallardo‐Torres, X. Chiappa‐Carrara
      First page: 1084
      Abstract: This study reports length‐weight relationships and growth parameters for Floridichthys polyommus Hubbs, 1936 and Fundulus persimilis Miller, 1955 from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatan Peninsula, Mexico. Specimens were collected between April 2009 and March 2010. The resulting length‐weight relationship for F. polyommus was: W = 0.0180 Lt3.37 and W = 0.0142 Lt3.35 for F. persimilis. This study presents the first estimation for both species of the von Bertalanffy growth model parameters, the growth performance index, the L50, and is the first report of the length‐weight relationship for F. persimilis.
      PubDate: 2014-04-09T03:57:26.933611-05:
      DOI: 10.1111/jai.12443
       
  • Length–weight and length–length relationships and length at
           first maturity for freshwater fish species of the Salto Santiago
           Reservoir, Iguaçu River Basin, Brazil
    • Authors: É. A. Gubiani; S. da S. Horlando
      First page: 1087
      Abstract: Length‐weight (LWR) and length‐length (LLR) relationships were estimated for 20 species and lengths at first maturity (L50) for six species of freshwater fishes caught in the Salto Santiago Reservoir, Iguaçu River Basin, Brazil. In nine species significant differences were found in the LWR between sexes. Average b‐value for species with no differences between sexes in LWR was 3.12 (SE = ±0.05). Average b‐value in LLR was 0.823. First references on LWRs and L50 are presented for 13 and four fish species, respectively, as well as the new maximum total lengths for eight species.
      PubDate: 2014-04-21T07:20:18.006574-05:
      DOI: 10.1111/jai.12444
       
  • Length‐weight relationships of 29 fish species from the Tucuruí
           Reservoir (Tocantins/Araguaia Basin, Brazil)
    • Authors: J. R. Garcia‐Ayala; E. M. Brambilla, F. A. Travassos, E. D. Carvalho, G. S. David
      First page: 1092
      Abstract: The length‐weight relationships (LWRs) are described for 29 fish species in the region of the Tucuruí Reservoir, located in the Tocantins/Araguaia Basin, northern Brazil. Fishes in fourteen sites were sampled seasonally for 10 years, from 2001 to 2010. Significant differences between sexes were found for two species, while 27 species had similar LWRs for males and females. The relationship of standard length and total length is presented for all species as well as the minimum and average size of reproductive females and seasonality of occurrence. No information on LWRs of these 29 species was heretofore available in FishBase.
      PubDate: 2014-05-06T06:52:48.982095-05:
      DOI: 10.1111/jai.12449
       
  • Length‐weight relationship of stingrays in Kuala Selangor, Malaysia
    • Authors: K. C. Lim; V. C. Chong, P. E. Lim, T. Yurimoto
      First page: 1096
      Abstract: Length‐weight relationships of three sympatric species of stingrays from a coastal mudflat, Malaysia were estimated. A total of 290 individuals (150 Himantura walga, 78 Dasyatis bennetti, and 57 Dasyatis zugei) were sampled using barrier net, gill net and beam trawl. The length‐weight relationship based on disc length and width generally showed positive allometric growth (b > 3) for all species. This study reports the first findings regarding the length‐weight relationships of these stingray species in Malaysian waters.
      PubDate: 2014-05-30T06:52:29.558482-05:
      DOI: 10.1111/jai.12455
       
  • Length‐weight relationships of fishes in the Wu Jiao nature reserve
           and adjacent areas, China
    • Authors: Y. Zeng; Y.‐Y. Huang, Y.‐B. Chen, Z.‐J. Li
      First page: 1099
      Abstract: The length‐weight relationships LWRs) (W = aLb) of four fish species caught in 2010–2012 from the Wujiao Nature Reserve and adjacent areas are reported. LWRs of these species are documented for the first time.
      PubDate: 2014-06-20T06:31:20.273872-05:
      DOI: 10.1111/jai.12461
       
  • Length–weight relationships of six freshwater fish species from the
           semiarid region of Brazil
    • Authors: J. L. Costa Novaes; R. Silva da Costa, B. Leite Mourato, D. Peretti
      First page: 1101
      Abstract: Evaluated were the length–weight relationships of six freshwater fish species caught in the Santa Cruz Reservoir in the semiarid region of Brazil: one Characidae, one Prochilodontidae, one Anostomidae, two Loricariidae and one Cichlidae, providing the first references of length–weight relationships and new maximum lengths for these species.
      PubDate: 2014-06-30T07:18:18.284352-05:
      DOI: 10.1111/jai.12481
       
  • Length‐weight relationships of four snowtrout species from the
           Kashmir Valley in India
    • Authors: F. A. Mir; J. I. Mir, R. Singh Patiyal, P. Kumar
      First page: 1103
      Abstract: Length–weight relationships (LWR) are presented for one species of the genus Schizopyge [S. curvifrons (Heckel, 1838)] and three species of the genus Schizothorax [S. esocinus (Heckel, 1838), S. labiatus (McClelland, 1842) and S. plagiostomus (Heckel, 1838)] from different water bodies of the Kashmir Valley, India. A total of 774 specimens were sampled and measured from January to November 2011. No information regarding LWRs of these species was available in FishBase.
      PubDate: 2014-06-20T06:31:24.097812-05:
      DOI: 10.1111/jai.12482
       
  • Survival of hatchery Gulf sturgeon (Acipenser oxyrinchus desotoi Mitchill,
           1815) in the Suwannee River, Florida: A 19‐year evaluation
    • Abstract: An experimental release of 1192 hatchery‐reared, individually PIT tagged, 220 days old (296–337 mm TL) Gulf sturgeon, Acipenser oxyrinchus desotoi, was undertaken in 1992 in the Suwannee River, Florida. The original objectives of the 1992 release experiment were to: (1) evaluate survival rate of cultured Gulf sturgeon in the wild vs survival rate of their wild 1992 cohort counterparts, (2) determine the differential effect of release site within the river upon long‐term survival, and (3) evaluate comparative growth rates of recaptured hatchery vs captured wild 1992 cohort Gulf sturgeon. The present investigation addressed those original objectives, plus an additional fourth objective: (4) evaluation of hatchery fish recapture rate change over the 19‐year experiment. The primary objective was to determine efficacy of potential conservation aquaculture for this species in terms of long‐term survival in the wild. Follow‐up 1993–2011 gill net sampling in freshwater reaches (rkm 4–237) and the estuarine river mouth (rkm −6 to 4) yielded recaptures representing 13.0% of the total released. Mean annual hatchery fish mortality (including emigration) rate estimated for the 19‐year period (1993–2011) was more than twice that for same cohort wild fish. Mark‐recapture survival probability (phi) for hatchery fish, 1993–2011, was substantially lower (0.733) than for their wild counterparts (0.888). Mean annual hatchery fish recapture rate, as a percentage of all 1992 cohort fish recaptures, declined significantly after age‐7, coinciding with age of onset of migration into the open Gulf of Mexico. Hypothesized causal factors may be differentially lower fitness in the marine habitat or permanent outmigration due to natal river imprinting failure. Hatchery fish recapture rates varied significantly for fish from the ten release sites, being highest near the river mouth, and lowest for the furthest upriver sites in the Suwannee River and its Santa Fe River tributary. Hatchery fish also displayed a significantly lower growth rate than their wild counterparts through age 3000 days. Cumulative hatchery fish mortality of 99.87% over 19 years predicts
       
  • Initial evaluation of the release programme for Dabry's sturgeon
           (Acipenser dabryanus Duméril, 1868) in the upper Yangtze River
    • Abstract: This paper evaluates the outcome of the first release programme for Acipenser dabryanus rehabilitation in its natural habitat and focuses specifically on the growth rate of released juveniles, and on the dispersal of the fish after release. To conserve and restore natural recruitment, the conservation propagation programme has released hatchery‐reared juveniles annually in the upper Yangtze River. This paper summarized the release activities and analysed post‐release monitoring data. From 2010 to 2012, 7030 juveniles aged 1–3 years were released in the Shuifu and Yibin reaches of the upper Yangtze River. Incidental catches of 112 samples were recorded during the three‐year observation period. Recapture sites were located between Yibin and Chongqing reaches (approximate range of 385 km), with 72.3% of the individuals recaptured within 20 km from the release site. Incidental catches were mainly in shallow water within 20 m of the riverbank. Body weight of the released sturgeon initially declined but this lost weight was soon regained. The low recaptured rate indicates that only a few of the released juveniles were able to survive and settle in the upper Yangtze River. The observed movement patterns suggest a potential additional downstream release site for future consideration to improve the performance of the released fish.
       
  • Current status of feeding stocks of the kaluga sturgeon Huso dauricus
           Georgi, 1775, and Amur sturgeon Acipenser schrenckii Brandt, 1889, in
           Russian waters
    • Abstract: Biological parameters of the kaluga Huso dauricus and Amur Acipenser schrenckii sturgeons have been analyzed in their foraging areas in Russian waters. Results show that both species are now sufficiently abundant only in catches from the lower Amur River, its mouth, and the Amur Estuary. The largest Amur sturgeon individuals occur in the estuary, while the largest kaluga sturgeon reside in the estuary as well as in the Sea of Okhotsk. Catches made in the river consist mainly of juvenile fish. The average body sizes of kaluga and Amur sturgeons in catches from the lower Amur River and the Amur Estuary have decreased significantly compared to records from 1929 to 1930. Between 2006 and 2011, the proportions of mature kaluga and Amur sturgeons in the river catches averaged 2.9 and 5.1%, respectively, and at its mouth and in the estuary by 42.6 and 32.8%, respectively. Abundance of kaluga sturgeon (age >1 year) in the lower Amur and the estuary in 2011 reached 345 000 individuals at a biomass of 7110 tonnes (t). Abundance of Amur sturgeon (age >1 year) in the same area and time reached 289 000 individuals at a biomass of 1946 t. The main stocks of the respective species (324 300 individuals or 94% in Kaluga, 263 570 individuals or 91.2% in Amur sturgeon) are concentrated in the Amur Estuary. To restore their populations in the Amur, a ban on all types of commercial fishing at the spawning grounds and juvenile foraging grounds should be implemented. It is also necessary to increase the number of hatchery‐reared juveniles and allow them to grow to a greater body size before release into the Amur.
       
  • How to sample juvenile Lake Sturgeon, (Acipenser fulvescens Rafinesque,
           1817), in Boreal Shield rivers using gill nets, with an emphasis on
           assessing recruitment patterns
    • Abstract: Adaptive management and recovery initiatives for long‐lived, late‐maturing species such as Lake Sturgeon, Acipenser fulvescens, are complicated by temporal lags. By the time anthropogenic impacts on critical periods (spawning, larval hatch, age‐0 survival) would be manifested in adult populations, decades might have passed. However, recruitment patterns and population trajectory responses (both positive and negative) can be identified by examining the juvenile life stage. This study describes and evaluates a gill net method for sampling juvenile Lake Sturgeon between 250 and 800 mm fork length (FL) resident in Boreal Shield rivers in relative proportion to their abundance. The method is based on previous observations of deepwater preference (>10–15 m), and employs mesh sizes of 25.4, 50.8, 76.2, 127.0 and 152.4 mm stretched measure. Selectivity curves were generated based on 1040 Lake Sturgeon captures from six reaches of the Winnipeg and Nelson rivers, Canada. A normal (common spread) curve approximated a normal distribution centered on ~390 mm FL, and relative selection exceeded 0.65 across the 250–800 mm FL range. For the Slave Falls Reservoir (Winnipeg River), Spearman's rank‐order correlation (ρ) for zone‐specific cohort‐frequency distributions in adjacent sampling years ranged from 0.85 to 0.93, while the score for the entire reservoir was 0.95, suggesting inter‐annual consistency. The method allows for rapid and robust assessments of relative abundance and cohort strength for juvenile Lake Sturgeon within large Boreal Shield river systems, and facilitates biological comparisons among reaches and over time. Incidentally, cohort frequency results derived herein indicate that juvenile recruitment in regulated Boreal Shield rivers can be erratic, irrespective of size of the spawning stock. Such a pattern could be an inherent characteristic of the species that needs to be accounted for when developing adaptive management and species recovery plans.
       
  • Effect of dietary carbohydrate sources on the growth performance, feed
           utilization, muscle composition, postprandial glycemic and glycogen
           response of Amur sturgeon, Acipenser schrenckii Brandt, 1869
    • Abstract: The present study was conducted to compare growth performance, feed utilization, muscle composition, and postprandial glycemic and glycogen responses of juvenile Amur sturgeon, Acipenser schrenckii, fed different carbohydrate diets in order to select the most appropriate carbohydrate sources for this species. Six experimental diets were formulated containing 22% glucose, fructose, maltose, dextrin, α‐starch or cornstarch, respectively. Triplicate groups of 20 fish (average weight: (4.7 ± 0.1) g, means ± SD) were randomly fed one of the six diets for eight weeks. Results showed that the weight gain rate was highest in fish fed the dextrin (716.0%) or α‐starch diet (782.9%), and lowest in fish fed the fructose diet (333.2%). Specific growth rate and feed efficiency showed a similar weight gain rate pattern. Apparent digestibility of dietary carbohydrate for Amur sturgeon was the fructose, glucose> maltose> dextrin> α‐starch > cornstarch diet; apparent digestibility of dietary protein was the fructose> glucose, maltose, dextrin> cornstarch> α‐starch diet. Contents of muscle moisture, ash and crude lipid were significantly affected by the difference in dietary carbohydrate sources (P  0.05). Dietary carbohydrate sources significantly affected plasma glucose and liver glycogen concentrations in sturgeon in different periods after feeding (P 
       
  • Effects of different dietary lipid sources on growth performance, tissue
           fatty acid composition and serum lipid indices of juvenile Amur sturgeon,
           Acipenser schrenckii Brandt, 1869
    • Abstract: The present study was conducted to investigate the effects of different dietary lipid sources on the growth performance, tissue fatty acid composition and serum lipids indices of juvenile Acipenser schrenckii. Seven experimental diets were formulated with 10% lipid originating from fish oil (FO), sunflower oil (SFO), tallow oil (TO), pork lard (PL), rapeseed oil (RO), corn oil (CO) and soybean oil (SBO), respectively. Triplicate groups of 20 Amur sturgeon [initial body weight (9.83 ± 0.19) g; means ± SD] were cultured in 405‐L flow‐through aquaria and assigned to the experimental diets for 8 weeks. Results showed that fish fed the SBO diet had the highest weight gain rate (611.29%), significantly higher than that of fish fed the FO (539.14%), CO (540.56%) or SFO (451.27%, the lowest) diet (P 
       
  • Verifying success of artificial spawning reefs in the St.
           Clair–Detroit River System for lake sturgeon (Acipenser fulvescens
           Rafinesque, 1817)
    • Abstract: Lake sturgeon (Acipenser fulvescens) were historically abundant in the St. Clair – Detroit River System (SCDRS), a 160 km river/channel network. In the SCDRS, lake sturgeon populations have been negatively affected by the loss/degradation of natural spawning habitat. To address habitat loss for lake sturgeon and other species, efforts are underway to restore spawning substrate by constructing artificial reefs. The main objective of this study was to conduct post‐construction monitoring of lake sturgeon egg deposition and larval emergence near two of these artificial reefs: Fighting Island Reef (FIR) in the Detroit River, and Middle Channel Reef in the St. Clair River. An additional site in the St. Clair River where lake sturgeon spawn on a coal clinker bed was also investigated. From 2010 to 2012, viable eggs and larvae were collected from all of these reefs, indicating that conditions are suitable for egg deposition, incubation, and larval emergence. In the St. Clair River, the results indicate the likelihood of other spawning sites upstream of these artificial reef sites.
       
  • Migration of juvenile and sub‐adult Chinese sturgeon Acipenser
           sinensis Gray, 1835 in the Yangtze River, China below the Gezhouba Dam
    • Abstract: Acoustic telemetry data and recapture information were collected to study the distribution and migration of sub‐adult and juvenile Chinese sturgeon Acipenser sinensis. From 2007 to 2012, 187 537 tagged cultured fish (4637 sub‐adults and 182 900 juveniles) were released at two sites on the Yangtze River. Subsequently, 482 fish were caught, comprising 198 cultured fish and 284 wild fish, mostly near sandbanks and sandbars with flat topography and slow water flow rates. Acoustic monitoring showed that a single sub‐adult fish migrated upstream to the spawning grounds just below the Gezhouba Dam, a distance of 157 km at an upstream ground speed of 0.40–1.40 km h−1 (mean, 0.70 km h−1). Nine acoustically monitored sub‐adults made a downstream migration of 45–1521 km at a ground speed of 0.08–3.80 km h−1. The ground migration speed of fish upstream to Wuhan (rkm 1678–1071) was significantly lower than that from Wuhan to the Yangtze estuary (rkm 1071–94). There was no significant difference in the ground migration speed between cultured and wild individuals. Knowledge of the movement and migration patterns of the stocked juvenile and sub‐adult Chinese sturgeon will help to locate areas of the downstream channel in the lower reaches of the Yangtze River critical to the sturgeon and to evaluate the potential impact of the Three Gorges Dam on their downstream migration.
       
 
 
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