Conservation planning requires understanding population sizes and trajectories. As with many imperiled species, green sturgeon (Acipenser medirostris) census data are limited, making it difficult to contextualize current threats and promote quantitative conservation goals. We combined spawning census, growth, and demographic data for the southern population of green sturgeon to build a population size and trajectory estimate. We generated a distribution of population size estimates and trajectories reflecting uncertainty from multiple sources. We then propagate these estimates through a demographic model to assess the potential impact of fishing bycatch. Our model suggests the population is below the recovery goal of 3,000 adults. The most probable current total population estimate (including juveniles) is approximately 10,000 fish (5,300-18,400 95% HDI), with 2,400 adults (2197-2624 95% HDI). Simulated fishing bycatch pressure on the adults and subadults reduced abundance by a median value of 0.4% per year, which could be an impediment to recovery. Fisheries bycatch is one of many threats this population faces; this integrated framework may be used to assess how other threats may affect this population.

Understanding postrelease effects of incidental capture on fish species of conservation concern is critically needed. We collaborated with commercial fishermen to estimate postrelease survival of green sturgeon (Acipenser medirostris) captured and released from bottom trawls used to target California halibut (Paralichthys californicus). We developed a method for interpreting acceleration, depth, and temperature data transmitted from pop-up satellite archival tags to classify the fate of individuals following capture and release in fishing operations. We first deployed-SeaTag-MOD satellite tags on known living and dead sturgeon to develop a support vector machine that uses accelerometer readings to classify tagged fish as alive or dead. In 2015 and 2016, fishermen and West Coast Groundfish Observer Program observers tagged 76 green sturgeon (69-135 cm fork length) encountered as bycatch, yielding 51 useable data sets. Eleven sturgeon were classified as having died after release, 9 of which died within our designated 21-d (504 h) study period. Some green sturgeon entered the San Francisco Bay Delta after being tagged, indicating movement between ocean and estuary environments. Research is needed to understand how to minimize effects of handling time and trawl bycatch mortality.

Overexploitation of wild populations due to the high economic value of caviar has driven sturgeons to near extinction. The high prices commanded by caviar on world markets have made it a magnet for illegal and fraudulent caviar trade, often involving low-value farmed caviar being sold as top-quality caviar. We present a new molecular approach for the identification of pure sturgeon species and hybrids that are among the most commercialized species in Europe and North America. Our test is based on the discovery of species-specific single nucleotide polymorphisms (SNPs) in the ribosomal protein S7, supplemented with the Vimentin gene and the mitochondrial D-loop. Test validations performed in 702 specimens of target and nontarget sturgeon species demonstrated a 100% identification success for Acipenser naccarii, A.fulvescens, A.stellatus, A.sinensis and A.transmontanus. In addition to species identification, our approach allows the identification of Bester and AL hybrids, two of the most economically important hybrids in the world, with 80% and 100% success, respectively. Moreover, the approach has the potential to identify many other existing sturgeon hybrids. The development of a standardized sturgeon identification tool will directly benefit trade law enforcement, providing the tools to monitor and regulate the legal trade of caviar and protect sturgeon stocks from illicit producers and traders, hence contributing to safeguarding this group of heavily threatened species.

Worldwide, sturgeons (Acipenseridae) are among the most endangered fishes due to habitat degradation, overfishing, and inherent life history characteristics (long life span, late maturation, and infrequent spawning). As most sturgeons are anadromous, a considerable portion of their life history occurs in estuarine and marine environments where they may encounter unique threats (e.g., interception in non-target fisheries). Of the 16 marine-oriented species, 12 are designated as Critically Endangered by the IUCN, and these include species commercially harvested. We review important research tools and techniques (tagging, electronic tagging, genetics, microchemistry, observatory) and discuss the comparative utility of these techniques to investigate movements, migrations, and life-history characteristics of sturgeons. Examples are provided regarding what the applications have revealed regarding movement and migration and how this information can be used for conservation and management. Through studies that include Gulf (Acipenser oxyrinchus desotoi) and Green Sturgeon (A. medirostris), we illustrate what is known about well-studied species and then explore lesser-studied species. A more complete picture of migration is available for North American sturgeon species, while European and Asian species, which are among the most endangered sturgeons, are less understood. We put forth recommendations that encourage the support of stewardship initiatives to build awareness and provide key information for population assessment and monitoring.

Background: The international wildlife trade is a key threat to biodiversity. Temporal genetic marketplace monitoring can determine if wildlife trade regulation efforts such as the Convention on International Trade in Endangered Species (CITES) are succeeding. Protected under CITES effective 1997, sturgeons and paddlefishes, the producers of black caviar, are flagship CITES species.Methodology/Principal Findings: We test whether CITES has limited the amount of fraudulent black caviar reaching the marketplace. Using mitochondrial DNA-based methods, we compare mislabeling in caviar and meat purchased in the New York City area pre and post CITES listing. Our recent sampling of this market reveals a decrease in mislabeled caviar (2006-2008; 10%; n = 90) compared to pre-CITES implementation (1995-1996; 19%; n = 95). Mislabeled caviar was found only in online purchase (n = 49 online/41 retail).Conclusions/Significance: Stricter controls on importing and exporting as per CITES policies may be having a positive conservation effect by limiting the amount of fraudulent caviar reaching the marketplace. Sturgeons and paddlefishes remain a conservation priority, however, due to continued overfishing and habitat degradation. Other marine and aquatic species stand to benefit from the international trade regulation that can result from CITES listing.

BACKGROUND AND AIMS:The shark fisheries of Madagascar remain largely unstudied. Remoteness makes fisheries monitoring challenging while the high value of shark fins combined with the extreme poverty in Madagascar creates intensive pressure on shark resources.MATERIALS AND METHODS:We use DNA barcoding and species-specific PCR assays to characterize shark fisheries in Antongil Bay in northeastern Madagascar.RESULTS:The 239 samples taken from individuals collected in 2001 and 2002 correspond to 19 species. The four most common species were Sphyrna lewini, Rhizoprionodon acutus, Carcharhinus brevipinna, and C. sorrah. Antongil Bay may be a breeding area for C. brevipinna, C. leucas, and S. lewini.CONCLUSION:Local names are generally not a useful proxy for monitoring the species harvested in the fishery. Conservation efforts should characterize species exploitation at present, create spatial and temporal fishing restrictions to protect endangered species, and restrict large mesh gillnets.

Management of declining fisheries of anadromous species sometimes relies heavily on supplementation of populations with captive breeding, despite evidence that captive breeding can have negative consequences and may not address the root cause of decline. The beluga sturgeon (Huso huso), a species threatened by the market for black caviar and reductions in habitat quality, is managed through harvest control and hatchery supplementation, with an emphasis on the latter. We used yield per recruit and elasticity analyses to evaluate the population status and current levels of fishing and to identify the life-history stages that are the best targets for conservation of beluga of the Ural River. Harvest rates in recent years were four to five times higher than rates that would sustain population abundance. Sustainable rates of fishing mortality are similar to those for other long-lived marine species such as sharks and mammals. Yield per recruit, which is maximized if fish are first harvested at age 31 years, would be greatly enhanced by raising minimum size limits or reducing illegal take of subadults. Improving the survival of subadult and adult females would increase population productivity by 10 times that achieved by improving fecundity and survival from egg to age 1 year (i.e., hatchery supplementation). These results suggest that reducing mortality of subadults and adult wild fish is a more effective conservation strategy than hatchery supplementation. Because genetics is not factored into hatchery management practices, supplementation may even reduce the viability of the beluga sturgeon.

A number of international treaties address the conservation of marine resources. The declining state of the world's oceans suggests that these treaties are not succeeding and could use improvement. The Convention on International Trade in Endangered Species (CITES) is increasingly embracing the conservation of marine species. We examine the evolution of marine species protection under CITES and illuminate some of the mechanisms used and challenges faced in implementing CITES protection. We found that clarification is needed on when and where CITES applies and how CITES should work with other treaties and institutions. The Society for Conservation Biology (SCB) can contribute to increased effectiveness of CITES for marine conservation. Foremost, the SCB community could foster dialogue on creating a broad vision of how CITES should apply to marine species and how it can synergistically interact with other important marine-conservation treaties and institutions. More specific contributions could focus on defining listing criteria for marine species, improving the science behind the nondetriment finding, and offering technical guidance on species proposals. A future role for SCB could be to contribute to the enhanced effectiveness of other marine conservation agreements such as the Convention on the Conservation of Migratory Species of Wild Animals, the International Whaling Commission, and the United Nations Convention on the Law of the Sea.

DNA barcoding efforts involving animals have focused on the mitochondrial cytochrome c oxidase subunit I (Cox1) gene. Some authors suggest that this marker might under-diagnose young species. Herein, we examine Cox1 and control region diversity in a sample of Siberian sturgeon (Acipenser baerii), a species with an extremely wide geographic distribution in the major rivers of Siberia and in Lake Baikal. Some authors currently recognize three subspecies within this species. These subspecies are reasonable candidates for species units detectable through DNA barcoding. The Cox1 gene illustrated no variation within the species, while the control region displayed statistically significant differences among the subspecies using analysis of molecular variance (AMOVA). Given the uniformity of Cox1 sequences recovered, Cox1 is probably a good region for barcoding A. baerii at the species level. Although control region variation among subspecies was significant, diagnostic differences were not found for any of the subspecies.

Madagascar's marine fisheries provide revenue and sustenance for the island nation. Antongil Bay, the largest shallow-water bay along Madagascar's eastern coast, harbors significant marine resources and is heavily utilized by traditional, artisanal (shark-fin) and industrial fisheries. Mean hourly catch rates are just under 1 kg/hour/fisher and mean daily catch rates are 4.4 kg/day/fisher. Beach seines, tamis (fine mesh seines), and combined use of gillnet and line were the most efficient gear types in terms of hourly and daily catch rates while gillnet and line were the most common gear types employed. Catch composition included 140 fish species from 69 families. Overall catch was dominated by species from Scombridae and Carangidae (Atule mate, Decapterus russelli, Megalaspis cordyla, Rastrilliger kanagurta). The Bay appears to be an important breeding habitat for scalloped hammerhead (Sphyrna lewini) and other species in the family Carcharhinidae. Given the multi-species and multi-sector nature of this fishery, ecosystembased management, wherein sensitive habitats are protected and limits are placed on destructive gear, is recommended, along with a zoning program to control resource-use overlap and encourage ownership.

Combined approaches utilizing tagging and genetic analysis can provide powerful insight into the biology and management of endangered sturgeons as described in a literature review herein. Since 2003, our team of USA and Republic of Kazakhstan researchers has attempted to use such techniques to study Ural River sturgeons. High-tech (satellite, acoustic) tagging methods were to be applied to examine movement and behavior of Ural River sturgeons within the River and the Caspian Sea and test hypotheses about sturgeon biology. In 2006, we successfully completed a satellite tagging project in which four adult sturgeons (three beluga, Huso huso, and one ship sturgeon Acipenser nudiventris) captured in the Ural River were equipped with Pop-up Archival Transmitting (PAT) satellite tags and released into the Caspian Sea. In 2007, efforts were made to initiate an acoustic tagging and tracking program within the Ural River to study sturgeon migratory behavior and locate spawning grounds. Tagging has also been used to measure the contribution of hatchery-produced sturgeons to that of the wild population. These studies were to be combined with genetic approaches to study the uniqueness and diversity of Ural River sturgeons. Overall, our program produced mixed results: some projects could not be undertaken, others produced only preliminary results, and some initiated long-term monitoring. Our work has implications for the conservation of Ural River sturgeons.

The Russian sturgeon, Acipenser gueldenstoedtii, is closely related to three other sturgeon species (A. persicus, A. naccarii and A. baerii), with populations in the Caspian Sea containing a cryptic lineage with an A. baerii-like mtDNA profile. Using morphological evidence (morphometrics, meristics) and additional genetic analysis (cytochrome b gene and control region sequencing), cryptic lineages within the Russian sturgeon and their relation to other closely related species of sturgeons are further examined. These data indicate that three genetic forms exist within what is presently known as A. gueldenstoedtii. These forms include the pure A. gueldenstaedtii and A. baerii-like individuals plus a third rare genetic form whose mtDNA is similar to the mtDNA of the Adriatic sturgeon, A. naccarii. Morphological comparison of the three forms and the Yenisei River A. baerii indicates that although the three forms of A. gueldenstoedtii are not different from one another, all three significantly differ from the Yenisei River A. baerii. Competing explanations, including translocation and centre of origin hypotheses are considered. The three genetic forms of A. gueldenstoedtii likely colonized different geographic areas during different geological periods, and subsequently evolved in these regions independently into the species currently recognized as A. gueldenstoedtii, A. naccarii and A. baerii.

The 27 extant species of sturgeons and paddlefishes (Order Acipenseriformes) represent a unique and relict lineage of fishes. Producers of coveted black caviar, sturgeons are one of the most valuable wildlife commodities on earth. The group is among the most endangered fishes with all species listed under Convention on International Trade in Endangered Species (CITES) Appendix I (two species) or 11 (25 species), only two species considered Lower Risk by IUCN, four of the nine US taxa and one Caspian species protected under the Endangered Species Act, and local extinctions recorded for 19 of 27 species. Despite their well-publicized imperilled status, commercial pressure on 15 species persists. Here, after reviewing the biological characteristics of sturgeons and paddlefishes and their commercial use, an over-view of global fisheries is presented. The synopsis demonstrates that, with few exceptions, sturgeon and paddlefish are imperilled across the globe and long-term survival in the wild is in jeopardy. All major sturgeon fisheries have surpassed peak productivity levels, with 70% of major fisheries posting recent harvests < 15% of historic peak catches and 35% of the fisheries examined crashing within 7-20 years of inception. Even in Caspian Sea fisheries, the most important globally, present catches are below 10% of historic peak landings. Improved domestic and international fisheries management and attention to habitat and species restoration is now needed. Although captive rearing offers promise for caviar alternatives and endangered species restoration, it must advance cautiously to avoid environmental harm. To ensure a continued supply of caviar and the survival of these unique fishes we offer recommendations for priority conservation action for the future.

The analysis of genetic data for the purpose of identifying conservation priorities may draw from one or more biological subdisciplines depending on the specific questions at hand. As such the proliferation of different methods for analyzing and interpreting genetic data in such fields as molecular systematics and population genetics has been paralleled in conservation. We explore the respective realms of utility for these fields and approaches by discussing the juxtaposition of analyses of character distributions with more commonly and often casually used tree-based analyses. In so doing, the biological, philosophical, and methodological convergences and conflicts of these frameworks are explicated using empirical examples, as are some of the areas of overlap among and disagreement over phylogenetic species criteria and other alternatives. In the arena of conservation biology, systematics and Population genetics complement one another and may facilitate the identification of management units at intraspecific levels, or more properly intra-nominal levels when species boundaries are defined according to The biological species concept. The comparison of these methods heightens the contrast between graphical representation of reciprocal monophyly at traditionally intra-nominal levels and the identification of groupings actually supported by fixed diagnostic characters as prospective conservation tools. Since character fixation is widely regarded as an early stage in the "ontogeny" of species evolution, character-based approaches to delineating management units provide a suitable framework from within which to explore the complementarity of the two major subdisciplines of evolutionary biology an(] their respective contributions to conservation.

A survey of three mitochondrial DNA regions (control region, NADH5, cytochrome b) and comprehensive sequencing of the control region (631-646 bps) was conducted to examine whether subspecies and geographic populations within three species of Eurasian sturgeons, Acipenser gueldenstaedtii, A. stellatus, and Huso huso, are genetically distinct. Neither subspecies nor populations exhibited diagnostic distinction or reciprocal monophyly in any gene region examined. For the control region, molecular variance analyses (AMOVA) indicate that most of the variance is because of differences among haplotypes within subspecies (H. huso: 99.6%,- A. stellatus: 95.0%, A. gueldenstaedtii: 81.0%) and populations (A. gueldenstaedtii: 76.1%). Significant pairwise F-values were found for all pairwise comparisons except for Sea of Azov and Caspian Sea A. gueldenstaedtii and Caspian Sea and Black Sea A. stellatus and H. huso. Only weak genetic differentiation is apparent between select subspecies and populations, reflective of biogeographic and management history. High genetic diversity within A. gueldenstaedtii suggests the possibility of additional population structure. Future research and management projects should consider these results.

Ecosystem-based fishery management (EBFM) is a new direction for fishery management, essentially reversing the order of management priorities so that management starts with the ecosystem rather than a target species. EBFM aims to sustain healthy marine ecosystems and the fisheries they support. Pikitch et al . describe the potential benefits of implementation of EBFM that, in their view, far outweigh the difficulties of making the transition from a management system based on maximizing individual species.