Atlantic 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

The federally endangered Shortnose Sturgeon Acipenser brevirostrum was once abundant in all major coastal river systems from the Saint John River, Canada, to the St. Johns River, Florida. During much of the 20th century, however, populations suffered major declines throughout their range from the combined effects of overfishing, pollution, and habitat loss. Although the species was a charter member of the Endangered Species Act, quantified population assessments are still lacking for many river systems throughout their range. Because river-specific assessments are critical for evaluating species recovery, the objective of this study was to quantify abundance and annual recruitment of Shortnose Sturgeon occupying the Savannah River, Georgia. Anchored gill nets and trammel nets fished during slack tides were used to sample juvenile and adult Shortnose Sturgeon in their summer holding areas during 2013-2015. Huggins closed-capture models in RMark were used to derive abundance estimates for each demographic group. The best models estimated that the Savannah River contained 81 (95% CI = 27-264) age-1 juveniles in 2013, 270 (162-468) in 2014, and 245 (104-691) in 2015. The models also estimated the river to contain 486 (198-1,273) age-2+ juveniles in 2013, 123 (69-235) in 2014, and 187 (81-526) in 2015. Similarly, the adult population was estimated to be 1,865 (784-4,694) individuals in 2013, 1,564 (1,005-2,513) in 2014, and 940 (535-1,753) in 2015. The results of this study provide the first population estimates available for Shortnose Sturgeon in the Savannah River. Additionally, the results suggest that the Savannah River likely contains the second largest population of Shortnose Sturgeon in Georgia. Future studies are needed in the Savannah River and other South Atlantic river systems to better evaluate Shortnose Sturgeon recovery status and the effects of river-specific anthropogenic modifications.

Increases in catch-and-release practices in addition to angler engagement in management activities to evaluate and improve the trophy potential of Muskellunge Esox masquinongy fisheries have become prevalent in recent decades. An expectation of conservative angling practices and regulations is that released fish can be recaptured by anglers at a later time and potentially at a larger size.Although several studies have evaluated Muskellunge recapture rates, no studies have estimated the number of recaptured Muskellunge relative to the number present in the population. Additionally, few studies have evaluated angling size selectivity and the potential benefits or biases of incorporating those data into traditional Muskellunge assessments. This study evaluated the proportion of Muskellunge that were caught and recaptured relative to the population estimates in two Minnesota water bodies and the potential length-related bias from angler-caught fish. Data were obtained from traditional sampling gears (i.e., trap netting, boat electrofishing) and angling by volunteer anglers in the Mississippi and Crow Wing rivers and Baby and Man lakes. Participating anglers captured 11-22% of the population, of which 1-3% were subsequently recaptured at both sites annually. Recaptured fish accounted for 5-16% of the annual catch. At the Mississippi River site, proportionally larger fish were angled compared with the modeled population size structure, whereas angler catch from Baby and Man lakes was similar to the modeled size structure, likely due to the differing techniques used by anglers in the two water bodies. A more thorough understanding of recapture rates and size selectivity may be particularly important when managing a lowdensity species as angling pressure and angler involvement in management activities increase.

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