Sturgeon Research Research Articles

Metabolomics in sturgeon research: a mini-review.

Sturgeons are ancient fish, with 27 species distributed in the Northern Hemisphere. This review first touches upon the significance of sturgeons in the context of their biological, ecological, and economic importance, highlighting their status as "living fossils" and the challenges they face in genomic research due to their diverse chromosome numbers. This review then discusses how omics technologies (genomics, transcriptomics, proteomics, and metabolomics) have been used in sturgeon research, which so far has only been done on Acipenser species. It focuses on metabolomics as a way to better understand how sturgeons work and how they react to their environment. Specific studies in sturgeon metabolomics are cited, showing how metabolomics has been used to investigate various aspects of sturgeon biology, such as growth, reproduction, stress responses, and nutrition. These studies demonstrate the potential of metabolomics in improving sturgeon aquaculture practices and conservation efforts. Overall, the review suggests that metabolomics, as a relatively new scientific tool, has the potential to enhance our understanding of sturgeon biology and aid in their conservation and sustainable aquaculture, contributing to global food security efforts.

A review of the nutritional value and biological activities of sturgeon processed byproducts.

Sturgeons are a type of subcold water fish distributed in eastern Europe, on both sides of the North Pacific, in eastern Asia, in western North America, and on the east coast of North America. Its production capacity is strong, and it is easy to breed. However, the sturgeon industry has the problems of a single product structure, a short industrial chain and poor market sales. In this context, developing the sturgeon industry is crucial to research the nutritional value of sturgeon processing byproducts and developing diversified products. Therefore, this paper summarizes the research on the nutritional value of sturgeon processing byproducts and the current situation of processing and utilization over the past 10 years. First, CiteSpace visual analysis software and the bibliometric analysis platform were used to analyze the status of sturgeon research. The Web of Science (WOS) database was used as the literature source to fit the keywords of sturgeon literature in the past ten years. After excluding the two keywords sturgeon and sturgeon meat, the relevant literature is analyzed and sorted, focusing on the literature in the last five years. Second, a comprehensive and in-depth review (sturgeon, processing, byproducts as the keywords to search Google Scholar and Web of Science) was conducted on the research of the nutritional components contained in sturgeon and the processing of nutritional components in byproducts to provide a reliable reference for the research and processing of the sturgeon industry.

Reproductive status of a remnant Lake sturgeon (Acipenser fulvescens) population: Spawning and larval drift in the lower Fox River, Wisconsin

AbstractThe Lower Fox River is a modified tributary of Green Bay, Lake Michigan that hosts a remnant Lake Sturgeon (Acipenser fulvescens) population. Reproduction has been confirmed, although annual spawning events have been described as small and concerns regarding the long‐term viability of the population remain. Contemporary and comprehensive surveys of spawning habitat, spawning stock, and production to the larval stage have not been conducted. The goal of this study was to describe spawning habitat, determine the size and demographic structure of the spawning stock, and quantify larval production (2017–2019) to identify impediments to population growth and recovery. Over 130 adults were present during annual spawning runs and spawning activity was consistently concentrated along the eastern riverbank. Adequate population structure exists to support reproductive success, but larval catch was low, ranging from 0 to 14 larvae captured annually. Evaluation of the riverbed below the De Pere Dam suggests the extent of the substrate available for spawning adult Lake Sturgeon is lower (~70% less) than previously described. Habitat deemed suitable for spawning exists offshore below the dam, but most habitat used for spawning is arranged along the eastern man‐made shoreline. However, nearshore spawning is problematic at this location due to fluctuating discharge from dam operation and periodic seiche events. Possible impediments limiting the success of Lake Sturgeon reproduction include dewatering of eggs, retention of eggs and larvae, algae colonization, and egg predation. We discuss these issues in the context of previous Lake Sturgeon research, future monitoring of spawning adults/larval production, and the likelihood that river habitat improvement will foster increased reproductive success.

A satellite-based mobile warning system to reduce interactions with an endangered species.

Earth‐observing satellites are a major research tool for spatially explicit ecosystem nowcasting and forecasting. However, there are practical challenges when integrating satellite data into usable real‐time products for stakeholders. The need of forecast immediacy and accuracy means that forecast systems must account for missing data and data latency while delivering a timely, accurate, and actionable product to stakeholders. This is especially true for species that have legal protection. Acipenser oxyrinchus oxyrinchus (Atlantic sturgeon) were listed under the United States Endangered Species Act in 2012, which triggered immediate management action to foster population recovery and increase conservation measures. Building upon an existing research occurrence model, we developed an Atlantic sturgeon forecast system in the Delaware Bay, USA. To overcome missing satellite data due to clouds and produce a 3‐d forecast of ocean conditions, we implemented data interpolating empirical orthogonal functions (DINEOF) on daily observed satellite data. We applied the Atlantic sturgeon research model to the DINEOF output and found that it correctly predicted Atlantic sturgeon telemetry occurrences over 90% of the time within a 3‐d forecast. A similar framework has been utilized to forecast harmful algal blooms, but to our knowledge, this is the first time a species distribution model has been applied to DINEOF gap‐filled data to produce a forecast product for fishes. To implement this product into an applied management setting, we worked with state and federal organizations to develop real‐time and forecasted risk maps in the Delaware River Estuary for both state‐level managers and commercial fishers. An automated system creates and distributes these risk maps to subscribers’ mobile devices, highlighting areas that should be avoided to reduce interactions. Additionally, an interactive web interface allows users to plot historic, current, future, and climatological risk maps as well as the underlying model output of Atlantic sturgeon occurrence. The mobile system and web tool provide both stakeholders and managers real‐time access to estimated occurrences of Atlantic sturgeon, enabling conservation planning and informing fisher behavior to reduce interactions with this endangered species while minimizing impacts to fisheries and other projects.

Antifungal effects of alcoholic extract of Thymus vulgaris on Siberian sturgeon (Acipenser baerii) eggs compared with malachite green effects

The economic losses due to fungal contamination in development of sturgeon and the side effects of malachite green in the environment are very important. Therefore, it is essential to investigate and introduce suitable natural substances instead of malachite green. The aim of this study was to compare antifungal effect of Thymus vulgaris with malachite green on fungi isolated from Siberian sturgeon eggs obtained from International Sturgeon Research Institute. The samples were inoculated in culture media (SDA) and Glucose-Peptone Agar at 25°C for 5-7 days and then isolated fungi were identified. The antifungal effect of T. vulgaris extract was evaluated by disc diffusion method and MIC and MFC of fungi was measured. In this study, Saprolegnia spp ., Fusarium spp ., Rhodotorula spp ., Penicillium spp ., Trichoderma spp ., Chrysosporium spp .and sterile hyphaewere isolated and identified from fertilized eggs of A. baerii. According to the results, T. vulgaris extract had a significant effect on all isolated fungal species. The most effective sample was observed on Saprolegnia and the least effective ones were Fusarium and Trichoderma. The MIC and MFC of alcoholic extract for Saprolegnia spp ., Fusarium spp., Rhodotorula spp ., Penicillium spp ., Trichoderma spp ., Chrysosporium spp ., sterile hyphae were ≥0.75, 3, 1.5, 1.5, 0.75, 1.5, ≤0.75 mg/ml, and ≥1.5, ≥3, 3, 3, 1.5, 3 and 1.5 mg/ml, respectively. Due to high frequency of Saprolegnia spp . in A. baerii eggs, and the significant effect of alcoholic extract of T. vulgaris, it could be used as a good alternative for malachite green to reduce the frequency of fungal contamination and its economic losses during reproductive seasons of A. baerii.

The use of trifluralin to control fungal infection and to increase hatching rate of fertilized eggs of brood ship sturgeon (Acipenser nudiventris) in Guilan Province

A brood ship sturgeon with the weight of 10 kg, produced 3.6 kg eggs. After the fertilization process, 300 g of eggs (approximately 8800±120 eggs) were distributed into each box of Youchtchenko incubator (each incubator has 4 boxes). The research was carried out with 4 treatments and 3 replications in each treatment. The research was conducted at the International Sturgeon Research Institute and Beheshti Sturgeon Restoration and Genetic Conservation Center, in 2017. Treatments included control (no added trifluralin herbicide) and 3 different concentrations of trifluralin, treatment 1 (0.1 mg L-1), treatment 2 (0.05 mg L-1), treatment 3 (0.025 mg L-1). Trifluralin was added 24 hours after placing the fertilized eggs in the incubator. 48 hours after incubation, the number of fungal eggs reached the highest level in treatments. However, in the control treatment it was significantly more than other treatments) p<0.05(. In treatments 2 and 3 the remaining eggs and the hatching rate, were significantly lower than other treatments) p<0.05(. Possibly, the use of trifluralin in two concentrations of 0.025 and 0.05 mg L-1 had negative effects, which may be due to low concentrations and use as a temporary bath. After 96 hours, the eggs were completely hatched. Hatching rate in treatment 1, was significantly more than control and treatments 2 and 3 (p<0.05). The results indicated that trifluralin can be successfully used in the proper function of Youchtchenko incubator, at a concentration of 0.1 mg L-1.

If you build it, will they come? Spawning habitat remediation for sturgeon

Habitat loss is a widely recognized contributor to global declines in sturgeon populations yet habitat remediation has been limited for this highly endangered group of fish. In support of future sturgeon restoration efforts, this review examines habitat remediation needs and uncertainties. Consideration of the bio‐spatial scale of remediation identified needs ranging from local to the whole river scale. Additionally, the context of remediation ranges from reintroducing sturgeon to habitats where they have been extirpated to conservation of currently functional habitat. While multiple remediation scales and contexts are discussed, the focus on spawning and early rearing habitat and associated biological and physical monitoring reflects the range of current projects and the importance of early rearing habitats. Four case studies are presented that examine four distinct remediation contexts (mitigation, rejuvenation, re‐creation, repatriation) and three bio‐spatial scales (whole river, spawning reach, spawning location) under which remediation has been attempted. Evaluation of existing remediation works indicates that many show limited long‐term success, which is most often a response to substrate infilling in remediated habitats. Material presented in this review will help align sturgeon research and monitoring approaches in support of effective remediation. The limited number of remediation projects to‐date attests to the importance of learning from existing projects and cross‐species comparisons, to maximize the effectiveness of future restoration efforts.

Expression Patterns of Atlantic Sturgeon (Acipenser oxyrinchus) During Embryonic Development.

During teleost ontogeny the larval and embryonic stages are key stages, since failure during this period of tissue differentiation may cause malformations, developmental delays, poor growth, and massive mortalities. Despite the rapid advances in sequencing technologies, the molecular backgrounds of the development of economically important but endangered fish species like the Atlantic sturgeon (Acipenser oxyrinchus) have not yet been thoroughly investigated. The current study examines the differential expression of transcripts involved in embryonic development of the Atlantic sturgeon. Addressing this goal, a reference transcriptome comprising eight stages was generated using an Illumina HiSequation 2500 platform. The constructed de novo assembly counted to 441,092 unfiltered and 179,564 filtered transcripts. Subsequently, the expression profile of four developmental stages ranging from early (gastrula) to late stages of prelarval development [2 d posthatching (dph)] were investigated applying an Illumina MiSeq platform. Differential expression analysis revealed distinct expression patterns among stages, especially between the two early and the two later stages. Transcripts upregulated at the two early stages were mainly enriched in transcripts linked to developmental processes, while transcripts expressed at the last two stages were mainly enriched in transcripts important to muscle contraction. Furthermore, important stage-specific expression has been detected for the hatching stage with transcripts enriched in molecule transport, and for the 2 dph stage with transcripts enriched in visual perception and lipid digestion. Our investigation represents a significant contribution to the understanding of Atlantic sturgeon embryonic development, and transcript characterization along with the differential expression results will significantly contribute to sturgeon research and aquaculture.

Adverse health effects and histological changes in white sturgeon (Acipenser transmontanus) exposed to dietary selenomethionine.

It has been shown that selenium (Se) released to the aquatic environment can have devastating effects on local wildlife. White sturgeon (Acipenser transmontanus) have a life history particularly susceptible to contaminants, and their protection is of interest as they are culturally and economically important, and many populations are classified as endangered. During the present 72-d dietary study, multiple signs of decreased health and Se lethality were observed. Juvenile white sturgeon were given diets containing 1.4 μg, 5.6 μg, 22.4 μg, or 104.4 μg selenomethionine/g food (dry mass). Selenium accumulated in muscle and liver tissue in a dose-dependent manner. Edema causing exophthalmos developed within 15 d and 23 d, and lethal effects occurred in 54% and 22% of fish in the high- and medium-dose groups, respectively. Growth and hepatosomatic index were significantly lower in the high-dose group, which also had a high incidence of food avoidance. Histology of the liver revealed a dose-dependent increase in melanomacrophage aggregates and decrease of energy stores, which indicated toxicity. These results indicate that white sturgeon are susceptible to the effects of Se accumulation over relatively short time periods. This stresses the need for continued sturgeon research and studies looking into the environmental fate and regulation of released Se. Environ Toxicol Chem 2016;35:1741-1750. © 2015 SETAC.

Confirmation of induced hybrid from female ship sturgeon (Acipenser nudiventrisLovetsky, 1828) and male Siberian sturgeon (Acipenser baerii, Brandt, 1869) using microsatellite markers

Journal of Applied IchthyologyVolume 31, Issue 6 p. 1002-1005 Short Communication Confirmation of induced hybrid from female ship sturgeon (Acipenser nudiventris Lovetsky, 1828) and male Siberian sturgeon (Acipenser baerii, Brandt, 1869) using microsatellite markers M. Hassanzadeh Saber, Corresponding Author M. Hassanzadeh Saber Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, Iran Author's address: Mohammad Hassanzadeh Saber, Genetics & Biotechnology Department, International Sturgeon Research Institute, P. O. Box: 41635-3464, Rasht, Iran. E-mail: saber.merag@gmail.comSearch for more papers by this authorS. Baradaran Noveiri, S. Baradaran Noveiri Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, IranSearch for more papers by this authorM. Pourkazemi, M. Pourkazemi Iranian Fisheries Science Research Institute, Agricultural Research Education and Extension Organization (AREEO), Tehran, IranSearch for more papers by this authorM. R. Nowruzfashkhami, M. R. Nowruzfashkhami Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, IranSearch for more papers by this authorM. Yarmohammadi, M. Yarmohammadi Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, IranSearch for more papers by this authorM. A. Salari Aliabadi, M. A. Salari Aliabadi Khorramshahr University of Marine Sciences and Technology, Khorramshahr, IranSearch for more papers by this authorH. Zolgharnein, H. Zolgharnein Khorramshahr University of Marine Sciences and Technology, Khorramshahr, IranSearch for more papers by this authorM. T. Ronagh, M. T. Ronagh Khorramshahr University of Marine Sciences and Technology, Khorramshahr, IranSearch for more papers by this author M. Hassanzadeh Saber, Corresponding Author M. Hassanzadeh Saber Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, Iran Author's address: Mohammad Hassanzadeh Saber, Genetics & Biotechnology Department, International Sturgeon Research Institute, P. O. Box: 41635-3464, Rasht, Iran. E-mail: saber.merag@gmail.comSearch for more papers by this authorS. Baradaran Noveiri, S. Baradaran Noveiri Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, IranSearch for more papers by this authorM. Pourkazemi, M. Pourkazemi Iranian Fisheries Science Research Institute, Agricultural Research Education and Extension Organization (AREEO), Tehran, IranSearch for more papers by this authorM. R. Nowruzfashkhami, M. R. Nowruzfashkhami Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, IranSearch for more papers by this authorM. Yarmohammadi, M. Yarmohammadi Genetics and Biotechnology Department, International Sturgeon Research Institute, Agricultural Research Education and Extension Organization (AREEO), Rasht, IranSearch for more papers by this authorM. A. Salari Aliabadi, M. A. Salari Aliabadi Khorramshahr University of Marine Sciences and Technology, Khorramshahr, IranSearch for more papers by this authorH. Zolgharnein, H. Zolgharnein Khorramshahr University of Marine Sciences and Technology, Khorramshahr, IranSearch for more papers by this authorM. T. Ronagh, M. T. Ronagh Khorramshahr University of Marine Sciences and Technology, Khorramshahr, IranSearch for more papers by this author First published: 03 October 2015 https://doi.org/10.1111/jai.12878Citations: 3Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume31, Issue6December 2015Pages 1002-1005 RelatedInformation

Modelling attempts utilized in sturgeon research: a review of the state-of-the art

Summary 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.

Relative age of references as a tool to identify emerging research fields with an application to the field of ecology and environmental sciences

Emerging scientific fields are commonly identified by different citation based bibliometric parameters. However, their main shortcoming is the existence of a time lag needed for a publication to receive citations. In the present study, we assessed the relationship between the age of references in scientific publications and the change in publication rate within a research field. Two indices based on the age of references are presented, the relative age of references and the ratio of references published during the preceding 2 years, and applied thereafter on four datasets from the previously published studies, which assessed eutrophication research, sturgeon research, fisheries research, and the general field of ecology. We observed a consistent pattern that the emerging research topics had a lower median age of references and a higher ratio of references published in the preceding 2 years than their respective general research fields. The main advantage of indices based on the age of references is that they are not influenced by a time lag, and as such they are able to provide insight into current scientific trends. The best potential of the presented indices is to use them combined with other approaches, as each one can reveal different aspects and properties of the assessed data, and provide validation of the obtained results. Their use should be however assessed further before they are employed as standard tools by scientists, science managers and policy makers.

Erratum to: Analysis of publications on sturgeon research between 1996 and 2010

The online version of the original article can be found under doi:10.1007/s11192-011-0583-7.I. Jaric´ (&)Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1,11000 Belgrade, Serbiae-mail: ijaric@imsi.rsI. Jaric´ J. GessnerLeibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, GermanyJ. GessnerSociety to Save the Sturgeon, Rostock, Germany

Analysis of publications on sturgeon research between 1996 and 2010

Sturgeon species are among the commercially most valuable and the most endangered groups of fish. To assess the existing literature published within the field of sturgeon research over the past 15 years (1996---2010) we applied a bibliometric approach, in order to identify patterns and trends of the published research in this field. The analysis was performed based upon articles obtained from the ISI Web of Knowledge online database. The results revealed that although all 27 sturgeon species have been objects of the research, species that are endangered or facing a high probability of extinction have received disproportionately less attention. White sturgeon (Acipenser transmontanus) was the most frequently studied species, but it was recently surpassed by Persian sturgeon (A. persicus). Early life phases have been among the central objects of the research, and genetics, especially the use of microsatellite DNA, is becoming increasingly popular and had the highest impact. Research related to aquaculture was prominent, while the research related to hybrids (as a commodity of aquaculture production) was decreasing in popularity. Papers dealing with conservation issues were most frequently focused on European sturgeon (A. sturio). A steady increase in the number of published articles over time was observed. However, the overall citation rate declined significantly over time. During the period reviewed, the sturgeon research published in peer reviewed journals dominantly originated from the USA and EU. Nevertheless, considering the current trend in output, it is very likely that the Asian countries, mainly Iran and China, will surpass them within the next 5---10 years. International and inter-institutional collaboration both tended to increase the impact of the research. Stimulation and improvement of the international cooperation should be considered as future priorities.

Evidence of Metapopulation Dynamics in Shortnose Sturgeon in the Southern Part of Their Range

AbstractThe shortnose sturgeon Acipenser brevirostrum is one of the most endangered members of the sturgeon family because of overexploitation, depressed population levels, and a shrinking range. The lack of historical data on shortnose sturgeon populations has led to an increase in sturgeon research over the last three decades; however, most recent studies have not focused on southern populations. The objective of this study was to estimate the abundance, annual survival, and temporary emigration rates of shortnose sturgeon in the Ogeechee River, Georgia. Shortnose sturgeon were captured with gill and trammel nets for a mark–recapture analysis from 1 June to 31 August in each of the 3 years from 2007 to 2009. Over the three summers of sampling, we conducted a total of 864 net sets and captured 168 individual shortnose sturgeon with an additional 51 recaptures. Our analysis revealed that the best‐fitting robust design population models incorporated interactions among water temperature, dissolved oxygen, and total effort in which capture and recapture probabilities were set equal and temporary emigration parameters were set to zero or held constant. Abundance estimates (95% confidence interval [CI]) were 404 (175–633), 264 (126–402), and 203 (32–446) individual sturgeon for 2007, 2008, and 2009, respectively. Population parameter estimates of annual survival and temporary emigration, combined with documented emigration and immigration of tagged individuals to and from the adjacent Altamaha River, provided evidence that the Ogeechee River stock is not discrete but possibly a metapopulation with the Altamaha River.

Influence of dietary l-selenomethionine exposure on growth and survival of juvenile Huso huso

The influence of different levels of dietary selenium in juvenile Huso huso was investigated in an 8 week growth trial. The present study was conducted at the International Sturgeon Research Institute with the objective to determine the effects of dietary selenium on growth, survival and whole body proximate composition. Six experimental diets were prepared by adding dietary concentrations of 0, 5, 10, 20, 40 and 80 μg g−1 diet selenium in the form of l-selenomethionine (SeMet) resulting in dietary concentrations of 1.26, 2.44, 3.01, 5.37, 11.56 and 20.26 μg Se g−1 diet on a dry weight basis. Juvenile H. huso with a mean weight of 3.5 ± 2.0 g and mean total length of 8.5 ± 2.5 cm were obtained from the Shahid Marjani hatchery and acclimated to formulated diets for 20 days, after which the fish were divided into six experimental groups and moved to 18, 500-L tanks with 13 fish per tank in a completely randomized design and fed diets supplemented with selenium. Three replicates were used for each experimental group. A one way anova and the correlations analysis were used to determine the relationship between the data at 95% confidence interval by spss software for windows (ver.14.0) and the means were compared using the Duncan’s Multiple Range Test. After 8 weeks mean survival rate was 75 ± 9% across all groups. Comparison of results showed that although good growth was observed in all groups, H. huso in experimental groups 4 and 5 fed above 11 μg Se g−1 diet showed faster and higher growth rates. No significant differences were observed among the hematological parameters studied. Selenium accumulated in all tissues studied in a dose dependent manner with highest levels observed in the liver. Results obtained showed that selenium had no histopathological effects on the tissues studied. It is evident from the results of this study that dietary concentrations of selenium between 11.56 and 20.26 μg Se g−1 diet can be considered the threshold dietary concentrations for suitable growth in juvenile H. huso. Further research is required to study the interactive effects of Se with other chemical and physical stressors in order to establish suitable supplementary levels of selenium to increase immune response and disease resistance in H. huso.

Current status and trends in shovelnose sturgeon (Scaphirhynchus platorynchus) management and conservation

Summary The objective of this study was to update information regarding the status of shovelnose sturgeon fisheries. Although a substantial amount of shovelnose sturgeon research has been conducted in the past decade, the study purpose was not to provide a comprehensive review of the literature; the primary interest was in the status, trends, and management of Scaphirhynchus platorynchus fisheries in North America. Biologists were surveyed in all 24 states within the native distribution of the species; results indicate that commercial harvest is currently permitted in eight states, recreational harvest is allowed in 13 states, and that regulations vary within rivers and jurisdictional boundaries. Although recreational exploitation of shovelnose sturgeon is thought to be low and not a significant threat to populations, commercial harvest is a major concern in states with a commercial fishery. In the last decade harvest has increased in all states with commercial shovelnose sturgeon fisheries, but recent implementation of regulations has decreased harvest in some states. Approximately half of the states with extant shovelnose sturgeon populations conduct routine monitoring of the species, and the understanding of shovelnose sturgeon populations is increasing.

Immune responses and behavior alterations of Persian sturgeon fingerlings Acipenser persicus exposed to sublethal concentrations of diazinon

Diazinon is an organophosphate pesticide widely used in agricultural areas (especially paddy fields) in Iran. Similar to other pesticides, diazinon may enter aquatic systems due to run-off and affect various organisms living in rivers and estuaries. Persian sturgeon Acipenser persicus is one of the most economically important species in the Caspian Sea, which enters Iranian rivers, such as the Sefidroud River, for breeding. Fish eggs hatch in the river and fingerlings migrate to the sea after a period of time. The International Sturgeon Research Institute in Rasht, Iran, produces and releases millions of fingerling sturgeons into the coastal area of the Caspian Sea annually and the fingerlings may thus be affected by this pesticide. This study was carried out to determine sublethal effects of diazinon on some hematological indices of Persian sturgeon under lab conditions. Fish were exposed to concentrations of 0, 0.01, 1.095 (0.25 LC50), 2.19 (0.5 LC50) or 3.285 ppm (0.75 LC50) diazinon and responses were studied after 12, 24 and 96 h. After 12 h exposure, the fingerlings exposed to 2.19 and 3.285 ppm revealed a series of abnormal responses such as muscle paralysis, change in gills and abdominal color, erratic swimming, rapid operculum movement, and loss of body balance. The exposed sturgeons also exhibited a significantly lower number of erythrocyte (RBC) and leukocyte count (WBC) after 24 and 96 h exposure. Similarly, after 96 h, there was a significant decrease in hematocrit (Htc). Results also revealed a decrease in lymphocyte numbers and an increase of meta neutrophils, band neutrophils and total neutrophils after 24 and 96 h diazinon. Data suggest that diazinon affects physiological and hematological functions of A. persicus, which may finally affect survival of the fish. Diazinon concentration of 0.01 ppm has been recorded in water of the Sefidroud River, where about five million Persian sturgeon fries are released annually by the Iranian department of fishery hatcheries. Since this level of pesticide was found to be toxic for fish fries, it is critical to avoid any toxic impact by regular monitoring of diazinon levels in the river water.

Mass culture of fairy shrimp Streptocephalus proboscideus (Crustacea ? Anostraca) and its use in larviculture of the Persian sturgeon, Acipenser persicus

This study was conducted with cysts of Streptocephalus proboscideus obtained from the University of Gent-Belgium. The cysts were hatched in Environmental Protection Agency (EPA) medium. The nauplii were reared at the Sturgeon Research Institute using a pure culture of Scenedesmus obliquus alga supplied at a density of 5 × 103 cell mL−1 that gradually increased to 1 × 104, 5 × 104 and 1 × 105 cell mL−1 with the growth of the nauplii. The nauplii attained sexual maturity and started producing cysts in 8 days and yielded a mean cyst number of 220±40 female−1 brood−1 cysts. These cysts were used in the larviculture of Persian sturgeon, Acipenser persicus (Borodin). Forty-three larvae of Persian sturgeon (mean weight: 15.4±1.1 mg; mean length: 27.1±2.7 mm) with roughly absorbed yolk sacs were stocked in three aquaria and fed S. proboscideus nauplii at 8-h intervals. By the end of the experiment (day 5), the mean weight and length of Persian sturgeon larvae were 51.4±13.3 mg and 20.7±1.4 mm respectively.

Modification of a Passive Gear to Sample Paddlefish Eggs in Sandbed Spawning Reaches of the Lower Yellowstone River

AbstractA passive sampling technique was developed to collect eggs and confirm potential spawning sites for paddlefish Polyodon spathula in sandbed reaches of the lower Yellowstone River, Montana and North Dakota. In 2000, egg collectors modeled after the mats used in sturgeon research proved difficult to retrieve from the riverbed and did not collect eggs. In 2001 and 2002, tubular egg collectors designed to remain suspended off the bottom were successfully retrieved 97% of the time and collected 130 acipenseriform eggs along suspected spawning sites (99% of differentiable eggs were genetically confirmed as paddlefish). In both years, eggs were typically collected in mid‐June after peak periods of Yellowstone River discharge and at river temperatures of 15–22°C. During collection periods in 2001 and 2002, 20% and 45% of retrieved tubes, respectively, had at least one egg, and 84% of all eggs were found on tubes retrieved from the channel thalweg. Although eggs were spatially distributed in a clumped manner at sample sites, the mean number of eggs per tube was low (&lt;4), suggesting either collector inefficiency, the inability to deploy collectors in close proximity to concentrations of spawning paddlefish, or the widespread distribution of spawning effort over the lower Yellowstone River.