Atlantic Sturgeon Populations Research Articles

Stock composition of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) encountered in marine and estuarine environments on the U.S. Atlantic Coast

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) is a large, anadromous fish native to the Atlantic Coast of North America. Although this species once supported important fisheries, centuries of exploitation and habitat degradation have resulted in dramatic declines, presumed extirpation in some rivers, and ultimately listing under the U.S. Endangered Species Act (ESA). Under the ESA, Atlantic sturgeon are listed as five separate Distinct Population Segments (DPSs), which form the basis for federal management. Despite state and federal protections Atlantic sturgeon still face significant threats to their recovery, including fisheries bycatch mortality, marine construction, dredging, dams, and vessel strikes. However, because subadult and adult Atlantic sturgeon migrate extensively across estuarine and marine environments and frequently form mixed-stock aggregations in non-natal habitats, it can be difficult to determine how these threats impact specific populations and DPSs. To better understand ontogenetic shifts in habitat use and stock-specific exposure to anthropogenic threats, we performed a mixed-stock analysis of 1704 Atlantic sturgeon encountered across the U.S. Atlantic Coast. Collections made north of Cape Cod, MA and south of Cape Hatteras, NC were dominated by individuals from regional stocks; however, we found extensive stock mixing in the mid-Atlantic region, particularly in coastal environments where individuals from all five DPSs were commonly observed. Subadults and adults that were encountered in offshore environments had moved, on average, 277 km from their natal source; however, 23% were sampled over 500 km from their natal river suggesting long-distance movements are relatively common in these age classes. Overall, our work highlights that Atlantic sturgeon populations are vulnerable to threats over vast areas and emphasizes the need for continued genetic monitoring to track recovery progress.

Fecundity of Atlantic sturgeon ( Acipenser oxyrinchus Mitchill, 1815) captured by the commercial fishery in the Saint John River, New Brunswick, Canada

Knowledge of fecundity in fishes is important for understanding life history, modeling population dynamics, developing fisheries management and determining conservation status. Sturgeon species are known for their high fecundity but to date only two populations of Atlantic sturgeon (Acipenser oxyrinchus Mitchill, 1815) have been examined for this aspect of their biology. The species is protected in most regions of eastern North America but the Saint John River, New Brunswick supports one of the two remaining commercial fisheries in Canada. Sixty females selected by this fishery were sampled for total length, weight, age, gonad weight and egg number. Absolute fecundity ranged from 153,630 to 1,306,626 eggs, with a mean fecundity of 582,832 ± 261,806 eggs. Absolute fecundity exhibited a significant positive relationship to increasing body weight but not to total length or age. Relative fecundity ranged from 129 to 216 eggs/g gonad weight and although it declined with both increasing body size and age the relationships were not significant. The Gonadosomatic Index (GSI) ranged from 1.3% to 27.0% with a mean of 7.8% ± 4.94 SD. Relative fecundity found in this study was higher and mean GSI lower than reported for other Atlantic sturgeon populations and other sturgeon species. Differences were probably due to location of the fishery downstream from spawning sites and selection of pre-spawning females by the commercial fishery.

Integrating side-scan sonar and acoustic telemetry to estimate the annual spawning run size of Atlantic sturgeon in the Hudson River

There is considerable interest in evaluating the status and trends of sturgeon populations, yet many traditional approaches to estimating the abundance of fishes are intractable due to their biology and rarity. Side-scan sonar has recently emerged as an effective tool for censusing sturgeon in rivers, yet challenges remain for censusing open populations that may visit specific habitats over periods of time (e.g., spawning runs). We use a hierarchical model to integrate side-scan sonar with acoustic telemetry, to estimate the proportion of a spawning run fitted with acoustic tags (12%; 95% CrI = 8%–16%) and extrapolate to the total run size in 2014. Our investigation represents a novel approach to generating run size estimates in a large river and provides the first estimate of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) spawning run size for the Hudson River ([Formula: see text] = 466; 95% CrI = 310–745) since the fishery moratorium in the 1990s. Our estimate suggests that the Hudson River holds one of the largest contemporary populations of Atlantic sturgeon, but also indicates that it remains sharply depleted relative to virgin conditions.

Comparing abundance estimates from closed population mark-recapture models of endangered adult Atlantic sturgeon

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 39:63-76 (2019) - DOI: https://doi.org/10.3354/esr00957 Comparing abundance estimates from closed population mark-recapture models of endangered adult Atlantic sturgeon J. E. Kahn1,2,*, C. Hager3, J. C. Watterson4, N. Mathies3, K. J. Hartman2 1National Marine Fisheries Service, Office of Protected Resources, Silver Spring, Maryland 20910, USA 2Division of Forestry and Natural Resources, West Virginia University, Morgantown, West Virginia 26506-6125, USA 3Chesapeake Scientific, Williamsburg, Virginia 23185, USA 4U.S. Department of the Navy, Naval Facilities Engineering Command, Atlantic Norfolk, Virginia 23508, USA *Corresponding author: jason.kahn@noaa.gov ABSTRACT: Atlantic sturgeon Acipenser oxyrinchus oxyrinchus were listed as 5 distinct population segments under the US Endangered Species Act in 2012. At that time, only 2 abundance estimates of the Atlantic sturgeon population were available: one from commercial fisheries landings in the Hudson River ending in 1995 and one from mark-recapture research in the Altamaha River, Georgia, in 2004 and 2005. In 2013, we verified spawning in the York River, Virginia, system and initiated a multiple-year mark-recapture study focusing on spawning-run abundance. We used a Schumacher-Eschmeyer model and Program CAPTURE to produce estimates of annual spawning abundances from 2013 to 2018. The Schumacher-Eschmeyer estimates of spawning-run abundance with 95% confidence intervals from 2013 to 2018 were 75 (31-190), 157 (115-244), 184 (150-238), 222 (137-576), 212 (157-328), and 145 (89-381), respectively. Because Atlantic sturgeon do not spawn every year, the trends in estimates do not suggest a recovering or declining population, but rather variability in proportions of the adult population that return to spawn each year. The estimates produced in Program CAPTURE using M0 (null), Mt (Chao Mt and Darroch), Mh (Chao Mh and Jackknife), and Mth (Chao Mth) models all produced similarly reliable estimates. The models that consider a behavioral response to initial capture (Mb, Mbh, and Mtb) failed to produce reliable estimates for this data, likely because as an endangered species, the dataset for Atlantic sturgeon was sparse. The Jackknife equation (model Mh) was the most precise every year with reliable accuracy and therefore is recommended. KEY WORDS: Anadromous · Conservation · Endangered species · Fish · Mark-recapture · Monitoring · Native fish · Population ecology · Population modeling Full text in pdf format Supplementary material PreviousNextCite this article as: Kahn JE, Hager C, Watterson JC, Mathies N, Hartman KJ (2019) Comparing abundance estimates from closed population mark-recapture models of endangered adult Atlantic sturgeon. Endang Species Res 39:63-76. https://doi.org/10.3354/esr00957 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 39. Online publication date: June 06, 2019 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2019 Inter-Research.

Genetic monitoring of natural sturgeon spawning in the lower Volga for the period 2017-2018

Genetic monitoring of natural sturgeon spawning in the lower Volga for the period 2017-2018

Contemporary and historical effective population sizes of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) is an anadromous fish of considerable conservation concern, following its long history of overfishing and exposure to a variety of other anthropogenic stressors. Though reaching a large size, population abundances (Nc) of Atlantic sturgeon are not easily surveyed using traditional fishery methods because of their relative scarcity and their many age classes, often exhibiting extensive and differential movements that render them not readily amenable to traditional sampling efforts. A metric of their vulnerability to inbreeding and a possible alternative to Nc for abundance monitoring is effective population size (Ne). We surveyed 14 Atlantic sturgeon populations across their range using a suite of DNA microsatellite markers. Contemporary levels of Ne ranged from 1 in the St. Marys River, Florida–Georgia, to 156 in the Hudson River, New York. Historical Ne estimates averaged about 11.5 × higher than contemporary estimates, with a high of 927 for the Kennebec River population. Because of a mix of life history characteristics that make traditional Ne estimates based on imperfectly mixed year classes of juveniles questionable, we propose and provide results of a new, more robust and diagnostic approach based on sequential cohorts, termed Ne Max. Although contemporary Ne values obtained were at levels that might be considered troublesome, we suggest that the unique life history factors of this species may render it more resistant than other taxa to inbreeding effects. Because of the many differences among populations in size, age, and sex ratio and in harvest histories, we do not believe that a reliable extrapolation factor between Ne and Nc is yet possible. However, ongoing monitoring of Ne and Nc in populations might be sensitive to population changes and could form the basis of determining a relationship between Ne and Nc.

DPS and population origin of subadult Atlantic Sturgeon in the Hudson River

Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus is listed under the U.S. Endangered Species Act as five Distinct Population Segments (DPS). Subadult Atlantic Sturgeon are highly migratory in coastal waters and often move to non-natal estuaries where they encounter a variety of anthropogenic disturbances that may compromise their survival. The Hudson River estuary hosts large numbers of subadult Atlantic Sturgeon seasonally, but their DPS and population origin is unknown. We used microsatellite DNA analysis at 11 loci and sequence analysis of the mitochondrial DNA control region in Individual Based Assignment testing to determine the origin of 148 subadult Atlantic Sturgeon that were collected in the tidal Hudson River estuary between river kilometers (RKM)5 and RKM 124 north of the Battery in New York City (RKM 0). We also determined the origin of eight dead specimens (subadults and adults) that were likely victims of vessel strikes and found floating between RKM27 and RKM60. We determined that 142 of 148 subadults assigned to the Hudson River (New York Bight DPS), the vast majority (138 of 142) with at least 95%, and usually, 100%, probability. All eight dead specimens assigned to the Hudson River with greater than 99% probability. Of the six subadult specimens that did not assign to the Hudson, two each assigned to the Kennebec River (Gulf of Maine DPS) and Delaware River (New York Bight DPS), one to the Ogeechee River (South Atlantic DPS), and one to the James River (Chesapeake Bay DPS). Our analysis allows the effects of anthropogenic threats in the Hudson River to be apportioned to the DPS and natal river populations of Atlantic Sturgeon found there and serves as a model for genetic population composition analysis for subadult Atlantic Sturgeon in other impacted estuaries.

Genetic differentiation of spring-spawning and fall-spawning male Atlantic sturgeon in the James River, Virginia.

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae) populations are currently at severely depleted levels due to historic overfishing, habitat loss, and pollution. The importance of biologically correct stock structure for effective conservation and management efforts is well known. Recent improvements in our understanding of Atlantic sturgeon migrations, movement, and the occurrence of putative dual spawning groups leads to questions regarding the true stock structure of this endangered species. In the James River, VA specifically, captures of spawning Atlantic sturgeon and accompanying telemetry data suggest there are two discrete spawning groups of Atlantic sturgeon. The two putative spawning groups were genetically evaluated using a powerful microsatellite marker suite to determine if they are genetically distinct. Specifically, this study evaluates the genetic structure, characterizes the genetic diversity, estimates effective population size, and measures inbreeding of Atlantic sturgeon in the James River. The results indicate that fall and spring spawning James River Atlantic sturgeon groups are genetically distinct (overall FST = 0.048, F’ST = 0.181) with little admixture between the groups. The observed levels of genetic diversity and effective population sizes along with the lack of detected inbreeding all indicated that the James River has two genetically healthy populations of Atlantic sturgeon. The study also demonstrates that samples from adult Atlantic sturgeon, with proper sample selection criteria, can be informative when creating reference population databases. The presence of two genetically-distinct spawning groups of Atlantic sturgeon within the James River raises concerns about the current genetic assignment used by managers. Other nearby rivers may also have dual spawning groups that either are not accounted for or are pooled in reference databases. Our results represent the second documentation of genetically distinct dual spawning groups of Atlantic sturgeon in river systems along the U.S. Atlantic coast, suggesting that current reference population database should be updated to incorporate both new samples and our increased understanding of Atlantic sturgeon life history.

Genetic characterization of Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus, in the Edisto River, South Carolina and identification of genetically discrete fall and spring spawning

Once widely abundant, most subpopulations of the endangered Atlantic sturgeon are now estimated to be only 1–10% of their historical levels. The Edisto River has been sampled for a long period and extensively for juvenile Atlantic sturgeon from separate spring- and fall-spawned cohorts. Our objectives are to characterize the genetic diversity, stability, adaptive potential, and potential genetic structure of Atlantic sturgeon in the Edisto River and to identify any past bottlenecks experienced by this species, as well as to conduct forward simulation modeling of the population under multiple population trajectories. Our results indicate that fall- and spring-spawned Atlantic sturgeon in the Edisto River are genetically distinct (overall $${{F}_{ST}}$$ = 0.092) with little gene flow or admixture between groups, both of which are diverse from a neutral genetic marker standpoint. Genetic diversity of both groups is on the higher end of published population diversity values. A lack of inbreeding and recent bottlenecks also bode well for these two groups of sturgeon, although future projections indicate a loss of allelic richness and genetic diversity even with population stability. Our effective population size estimates are moderate compared to published estimates for other Atlantic sturgeon populations. The most significant finding of our research is the genetic distinctness of the fall- and spring-spawned Atlantic sturgeon in the Edisto River, which may have several important ramifications for management of the species, including re-evaluating the demarcation of distinct population segments.

Recruitment of Juvenile Atlantic Sturgeon in the Savannah River, Georgia

AbstractAtlantic Sturgeon Acipenser oxyrinchus oxyrinchus were once abundant along the Atlantic coast of North America from the Saint Lawrence River, Canada, to the St. Johns River, Florida. Severe overfishing, coupled with habitat losses during the 1900s, resulted in major population declines that eventually led to the subspecies’ listing under the U.S. Endangered Species Act in 2012. Despite this listing, quantified recruitment data are largely lacking for most Atlantic Sturgeon populations, particularly those within the South Atlantic distinct population segment. The objective of this study was to quantify annual recruitment of Atlantic Sturgeon in the Savannah River, Georgia, by estimating annual abundance of age‐1, river‐resident juveniles. During the summers of 2013–2015, we used anchored gill nets and trammel nets to sample juvenile Atlantic Sturgeon throughout the Savannah River estuary. Ages of captured juveniles were determined by using length‐frequency analysis, and abundance of each juvenile age‐class was estimated with Huggins closed‐capture models in RMark. We estimated the Savannah River to contain 528 age‐1 juveniles in 2013, 589 in 2014, and 597 in 2015. The results from this study indicate that the Savannah River population is likely the second largest within the South Atlantic distinct population segment. Future studies are needed to determine the relative importance of the Savannah River as a natural source of recruitment for smaller, more imperiled populations in adjacent rivers. Consequently, we suggest that management efforts continue to prioritize the protection of both the population and the associated critical habitats within the Savannah River estuary.Received April 7, 2016; accepted June 28, 2016 Published online September 23, 2016

Dual annual spawning races in Atlantic sturgeon.

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus, Acipenseridae) populations in the United States were listed as either endangered or threatened under the Endangered Species Act in 2012. Because of the endangered/threatened status, a better understanding of Atlantic sturgeon life-history behavior and habitat use is important for effective management. It has been widely documented that Atlantic sturgeon reproduction occurs from late winter to early summer, varying clinally with latitude. However, recent data show Atlantic sturgeon also spawn later in the year. The group that spawns later in the year seems to be completely separate from the spring spawning run. Recognition of the later spawning season has drastically modified estimates of the population status of Atlantic sturgeon in Virginia. With the combination of new telemetry data and historical documentation we describe a dual spawning strategy that likely occurs in various degrees along most, if not all, of the Atlantic sturgeon's range. Using new data combined with historical sources, a new spawning strategy emerges which managers and researchers should note when determining the status of Atlantic sturgeon populations and implementing conservation measures.

Shortnose Sturgeon and Atlantic Sturgeon in the Kennebec River System, Maine: a 1977–2001 Retrospective of Abundance and Important Habitat

AbstractLittle was known about the populations of Shortnose Sturgeon Acipenser brevirostrum and Atlantic Sturgeon A. oxyrinchus in the Kennebec, Androscoggin, and Sheepscot River estuaries (the Kennebec system) in Maine, prompting a series of field studies spanning the years 1977–2001. Although the impetus for these studies varied, common objectives were to estimate population abundances and locate habitat important to the conservation of both species. During 16 years of gill‐net sampling, we caught 3,372 Shortnose Sturgeon and 403 Atlantic Sturgeon. On the basis of two mark–recapture studies, the adult Shortnose Sturgeon population in the Kennebec system was estimated to be 5,117 (95% confidence interval, 4,206–6,279) for the period 1977–1981 and 9,436 (7,542–11,888) for the period 1998–2000. Gill‐net sampling led to the identification of two spawning areas in the Kennebec system. One was an approximately 0.7‐km‐long reach immediately downstream of Brunswick Dam in the Androscoggin estuary, and the other was an approximately 26‐km‐long reach immediately downstream of Edwards Dam in the upper Kennebec estuary. Shortnose Sturgeon were caught at both locations, while Atlantic Sturgeon were documented only in the upper Kennebec estuary. Acoustic telemetry was used to identify a wintering site in Merrymeeting Bay that was used by Shortnose Sturgeon.

Use of the SAFE Index to Evaluate the Status of a Summer Aggregation of Atlantic Sturgeon in Minas Basin, Canada, and the Implication of the Index for the USA Endangered Species Designation of Atlantic and Shortnose Sturgeons

Sturgeon species worldwide have undergone population declines due to habitat alteration and overexploitation and many are listed by the International Union for Conservation of Nature (IUCN) and national agencies. Atlantic and shortnose sturgeon on the east coast of North America are listed as “endangered” or “threatened” over most of their ranges. It has been proposed, however, that IUCN risk categories are ambiguous and do not consider the threat status of a species in relation to a minimum viable population level. Here, we examine the Species Ability to Forestall Extinction (SAFE) Index, which is a heuristic measure of a species relative distance from extinction, and other available information on Atlantic and shortnose sturgeon with regard to the risk status of the two species. To move beyond a ‘tipping point’ designation of threatened, the SAFE Index requires a species abundance of 5000 adults (SAFE Index = 0.0). DNA and mark-recapture data for Atlantic sturgeon in Minas Basin, Canada indicates a USA/Canada mixed stock of ∼10,000 fish aggregate there in summer. The SAFE Index for this population is 0.28 indicating abundance is within the “vulnerable” threshold range for the Index although it includes but a small portion of the Atlantic sturgeon in the western Atlantic. Estimates for the east coast of North America suggest the Atlantic sturgeon population could consist of ∼177,000 sub adults and adults for a SAFE Index of 1.55. Additionally, the present spawning range of Atlantic sturgeon in North America is ∼99% of the historically known range and the number of stocks is near the historic level (33+) which means the species does not meet IUCN criteria for listing. Similarly, shortnose sturgeon has an Atlantic coast population of ∼96,800 adults (SAFE Index of 1.29) and a species range and number of stocks (26+) that has not changed substantially from the historical situation. Since the abundance of Atlantic and shortnose sturgeon are well above the SAFE threshold for “threatened” and they lack other accepted criteria for endangered or threatened designation, we conclude that the risk status of both species should be reconsidered.

Microsatellite multiplex assay for the analysis of Atlantic sturgeon populations.

We have developed a multiplex assay covering 16 microsatellite loci, amplified in four polymerase chain reaction (PCR) assays, and loaded on the ABI DNA Analyzer in two separate panels. The assay was tested on 603 individuals originating from wild populations and hatchery stocks of Atlantic sturgeon. The assay was also tested on 12 individuals of European sturgeon and appeared to be almost equally useful. The multiplex assay designed in this study can be successfully applied in studies requiring high genetic resolution, such as relatedness analysis, selective breeding programs, and stock identification of Atlantic sturgeon.Electronic supplementary materialThe online version of this article (doi:10.1007/s13353-014-0216-y) contains supplementary material, which is available to authorized users.

Potential for Electropositive Metal to Reduce the Interactions of Atlantic Sturgeon with Fishing Gear

Atlantic sturgeon (Acipenser oxyrhynchus) populations have been declared either endangered or threatened under the U.S. Endangered Species Act. Effective measures to repel sturgeon from fishing gear would be beneficial to both fish and fishers because they could reduce both fishery-associated mortality and the need for seasonal and area closures of specific fisheries. Some chondrostean fishes (e.g., sturgeons and paddlefishes) can detect weak electric field gradients (possibly as low as 5 Μv/cm) due to arrays of electroreceptors (ampullae of Lorenzini) on their snout and gill covers. Weak electric fields, such as those produced by electropositive metals (typically mixtures of the lanthanide elements), could therefore potentially be used as a deterrent. To test this idea, we recorded the behavioral responses of juvenile Atlantic sturgeon (31-43 cm fork length) to electropositive metal (primarily a mixture of the lanthanide elements neodymium and praseodymium) both in the presence and absence of food stimuli. Trials were conducted in an approximately 2.5 m diameter × 0.3 m deep tank, and fish behaviors were recorded with an overhead digital video camera. Video records were subsequently digitized (x, y coordinate system), the distance between the fish and the electropositive metal calculated, and data summarized by compiling frequency distributions with 5-cm bins. Juvenile sturgeon showed clear avoidance of electropositive metal but only when food was present. On the basis of our results, we conclude that the electropositive metals, or other sources of weak electric fields, may eventually be used to reduce the interactions of Atlantic sturgeon with fishing gear, but further investigation is needed.

Consequences of Incidental Otter Trawl Capture on Survival and Physiological Condition of Threatened Atlantic Sturgeon

AbstractAtlantic Sturgeon Acipenser oxyrinchus aggregate in Minas Basin in the inner Bay of Fundy, Nova Scotia, during summer, presumably to feed on abundant intertidal invertebrates. The Atlantic Sturgeon aggregation is composed of multiple stocks from Canada and the USA. Government agencies from both nations have recently recognized Atlantic Sturgeon as threatened or endangered due to overfishing and habitat degradation. Little is known about the fate of Atlantic Sturgeon that are captured as bycatch in fisheries targeting other species, making it difficult to determine the extent to which bycatch is contributing to the Atlantic Sturgeon population's decline. To characterize the effects of otter trawl capture and release on Atlantic Sturgeon, we calculated a minimum survival rate for fish after catch and release by using acoustic telemetry, and we examined physiological indicators of stress. The minimum postrelease survival rate from otter trawl capture events was high (94% survival). Results also demonstrated that the magnitude of blood lactate in trawl‐captured fish relative to experimental control fish increased with longer handling times. Trawl capture and handling did not cause significantly elevated levels of blood glucose or cortisol relative to those of controls. Minimization of handling time (i.e., time on deck) should be a priority in trawl fisheries that capture Atlantic Sturgeon as bycatch. Future studies should attempt to quantify the postcapture behavior of these fish to better understand whole‐organism condition after fisheries encounters.

Stock Origins of Subadult and Adult Atlantic Sturgeon, Acipenser oxyrinchus, in a Non-natal Estuary, Long Island Sound

The anadromous acipenserid Atlantic sturgeon Acipenser oxyrinchus was listed in 2012 under the U.S. Endangered Species Act as having four endangered and one threatened distinct population segment (DPS) in American waters. Anthropogenic activities outside of natal estuaries, particularly bycatch, may hinder the abilities of some populations to rebuild. Most Atlantic sturgeon are residential for their first 2–6 years within their natal estuaries, whereas older subadults and adults may migrate to non-natal estuaries and coastal locations. Previous studies demonstrated that subadults and adults aggregate during summer at locations in Long Island Sound (LIS) and its tributary, the Connecticut River; however, the population origin of these fish is unknown. Because of its geographic proximity and relatively robust population, we hypothesized that the LIS and Connecticut River aggregations were almost solely derived from the Hudson River. We used microsatellite nuclear DNA analysis at 11 loci and mitochondrial DNA control region sequence analyses to estimate the relative contributions of nine Atlantic sturgeon populations and the five DPS to these aggregations using individual-based assignment tests and mixed-stock analysis. From 64 to 73 % of specimens from LIS were estimated to be of Hudson origin. Similarly, 66–76 % of specimens from the Connecticut River were of Hudson origin. However, moderate numbers of specimens were detected from distant spawning populations in the southeastern DPS and from two populations once thought to be extirpated or nearly so, the James River (6–7.3 %), and the Delaware River (7.6–12 %). Additionally, specimens were detected from all five DPS in both the LIS and Connecticut River collections. These results highlight the difficulty of evaluating the status of individual Atlantic sturgeon populations because of the propensity of subadults and adults to migrate for extended duration to distant sites where they may be vulnerable to anthropogenic disturbances.

Isolation of cells from Atlantic sturgeon Acipenser oxyrinchus oxyrinchus and optimization of culture conditions

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 14:67-75 (2011) - DOI: https://doi.org/10.3354/ab00383 Isolation of cells from Atlantic sturgeon Acipenser oxyrinchus oxyrinchus and optimization of culture conditions B. Grunow*, S. Noglick, C. Kruse, M. Gebert Fraunhofer Research Institution for Marine Biotechnology, Fraunhofer Society, Paul-Ehrlich-Straße 1–3, 23562 Lübeck, Germany *Email: bianka.grunow@emb.fraunhofer.de ABSTRACT: We describe a method for fast and easy isolation of cells via trypsin digestion from larvae of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus resulting in a stable, well-proliferating cell culture. The culture conditions for these cells were optimized with the aim of supporting the production of high amounts of biomass. To enhance cell growth and cell density, 4 different cultivation temperatures as well as commercially available carp serum (CS) and fetal calf serum (FCS) at different concentrations were tested and evaluated. Cell growth was measured via an impedance-based online cell-monitoring system (xCELLigence). These results showed the best cultivation temperature to be at 25°C and a media composition of Dulbecco’s modified Eagle’s medium (DMEM) supplemented with either 10 or 20% FCS or 5% CS. The cells were stable in the process of long-term cultivation over 33 passages and could be cryo-preserved. Immunocytochemical analysis revealed that the cells expressed proteins of different blastodermic layers. Ectodermic glia fibrilliary acid protein, vigilin (mRNA transport protein), and pan cytokeratin were abundant. This fast-growing cell culture provides an important tool for research on Atlantic sturgeon populations. KEY WORDS: Primary culture · Culture condition · Serum · Sturgeon · Teleost fish Full text in pdf format PreviousNextCite this article as: Grunow B, Noglick S, Kruse C, Gebert M (2011) Isolation of cells from Atlantic sturgeon Acipenser oxyrinchus oxyrinchus and optimization of culture conditions. Aquat Biol 14:67-75. https://doi.org/10.3354/ab00383 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 14, No. 1. Online publication date: December 06, 2011 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2011 Inter-Research.

Abundance and Recruitment of Juvenile Atlantic Sturgeon in the Altamaha River, Georgia

AbstractJuvenile Atlantic sturgeon Acipenser oxyrinchus remain in natal rivers for several years prior to out‐migrating to marine environments during later portions of their life history. Data regarding river‐resident juvenile population dynamics are unknown. During the summers of 2004–2007, we performed mark–recapture of juvenile Atlantic sturgeon in the Altamaha River to assess age‐specific abundance, apparent survival, per capita recruitment, and factors influencing recruitment. Estimates indicated that juvenile abundance ranged from 1,072 to 2,033 individuals, and age‐1 and age‐2 individuals comprised greater than 87% of the juvenile population, while age‐3 or older individuals constituted less than 13% of the population. Estimates of apparent survival and per capita recruitment from Pradel models indicated that the juvenile population experienced high annual turnover: apparent survival rates were low (<33%), and per capita recruitment was high (0.82–1.38). Fall discharge, which had a positive relationship with recruitment, was the only factor assessed that significantly explained time variation in per capita recruitment. The findings of this study suggest that juvenile populations at the southern extreme of the Atlantic sturgeon's range may remain in natal rivers for less time than northern counterparts. This is further evidence of life history differences between northern and southern populations of Atlantic sturgeon. Potential findings of density dependence could have major implications for both population recovery and management of this species.

Atlantic Sturgeon Vessel‐Strike Mortalities in the Delaware Estuary

AbstractThe Atlantic Sturgeon Status Review Team has recommended that the Secretary of Commerce list the New York Bight distinct population segment of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus), which includes the Delaware River and Hudson River populations, as threatened under the federal Endangered Species Act. Between 2005 and 2008, a total of 28 Atlantic sturgeon mortalities were reported in the Delaware Estuary. Sixty‐one percent of the mortalities reported were of adult size and 50% of the mortalities resulted from apparent vessel strikes. The remainder of the mortalities were too decomposed to ascertain the cause of death, but the majority were likely the result of vessel strikes. For small remnant populations of Atlantic sturgeon, such as that in the Delaware River, the loss of just a few individuals per year due to anthropogenic sources of mortality, such as vessel strikes, may continue to hamper restoration efforts. An‐egg‐per‐recruit analysis demonstrated that vessel‐strike mortalities could be detrimental to the population if more than 2.5% of the female sturgeon are killed annually. We report on our observations of vessel‐strike mortalities in the Delaware Estuary, discuss the possible implications for the Delaware River population, and recommend further research.