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Abstract: Wire‐mesh traps are extensively used to harvest blue crabs Callinectes sapidus but also capture over 40 other species. Numerous studies have evaluated bycatch reduction devices (BRDs) to reduce the incidental capture of one species, the diamondback terrapin Malaclemys terrapin, since 1992. Despite decades of research, widespread adoption of BRDs as a conservation action has not occurred, which partly stems from seemingly conflicting results from a multitude of BRD designs along the U.S. Atlantic and Gulf of Mexico coasts. In this study, we developed a simple scoring system to assess the probability of trap entry by legal‐sized (≥12.7‐cm carapace width; n = 736) blue crabs as well as trap exclusion of diamondback terrapins (n = 985) based on morphometric measurements for both species. Probability of entry or exclusion for each legal‐sized blue crab and diamondback terrapin was assessed for each of 8,196 theoretical BRD sizes encompassing the range of BRD widths and heights actually tested since 1992. Predictive relationships for trap entry or exclusion for each theoretical BRD size were evaluated as a function of three geometric BRD attributes: BRD area (cm2), diagonal BRD opening (cm), and the ratio of BRD width to height. Comparison of observed (35 data sets) versus predicted (entry or exclusion probabilities for BRDs) catches for both species revealed that BRDs have performed as predicted for legal‐sized blue crab catch (slope = 0.99; >81,000 crabs) but have captured considerably fewer diamondback terrapins than predicted based on BRD size alone (slope = 0.28; 1,430 diamondback terrapins). Analyses also substantiated superior (i.e., >30% better) diamondback terrapin exclusion potential for a BRD we designed that measured 5.1–6.4 cm (height) × 7.3 cm (width). Increasing the width of this BRD by 0.4 cm would also achieve a 99% capture probability for legal‐sized blue crabs, comparable to other widely tested and marketed BRD designs. [ABSTRACT FROM AUTHOR]

Seasonal trawling was conducted randomly in coastal (depths of 4.6-17 m) waters from St. Augustine, Florida, (29.9°N) to Winyah Bay, South Carolina (33.1°N), during 2000-03, 2008-09, and 2011 to assess annual trends in the relative abundance of sea turtles. A total of 1262 loggerhead sea turtles (Caretta caretta) were captured in 23% (951) of 4207 sampling events. Capture rates (overall and among prevalent 5-cm size classes) were analyzed through the use of a generalized linear model with log link function for the 4097 events that had complete observations for all 25 model parameters. Final models explained 6.6% (70.1-75.0 cm minimum straight-line carapace length [SCLmin]) to 14.9% (75.1-80.0 cm SCLmin) of deviance in the data set. Sampling year, geographic subregion, and distance from shore were retained as significant terms in all final models, and these terms collectively accounted for 6.2% of overall model deviance (range: 4.5-11.7% of variance among 5-cm size classes). We retained 18 parameters only in a subset of final models: 4 as exclusively significant terms, 5 as a mixture of significant or nonsignificant terms, and 9 as exclusively nonsignificant terms. Four parameters also were dropped completely from all final models. The generalized linear model proved appropriate for monitoring trends for this data set that was laden with zero values for catches and was compiled for a globally protected species. Because we could not account for much model deviance, metrics other than those examined in our study may better explain catch variability and, once elucidated, their inclusion in the generalized linear model should improve model fits. [ABSTRACT FROM AUTHOR]

Trawling was conducted in the Charleston, South Carolina, shipping channel between May and August during 2004-07 to evaluate loggerhead sea turtle (Caretta caretta) catch rates and demographic distributions. Two hundred and twenty individual loggerheads were captured in 432 trawling events during eight sampling periods lasting 2-10 days each. Catch was analyzed by using a generalized linear model. Data were fitted to a negative binomial distribution with the log of standardized sampling effort (i.e., an hour of sampling with a net head rope length standardized to 30.5 m) for each event treated as an offset term. Among 21 variables, factors, and interactions, five terms were significant in the final model, which accounted for 45% of model deviance. Highly significant differences in catch were noted among sampling periods and sampling locations within the channel, with greatest catch furthest seaward consistent with historical observations. Loggerhead sea turtle catch rates in 2004-07 were greater than in 1991-92 when mandatory use of turtle excluder devices was beginning to be phased in. Concurrent with increased catch rates, loggerheads captured in 2004-07 were larger than in 1991-92. Eighty-five percent of loggerheads captured were ≤75.0 cm straight-line carapace length (nuchal notch to tip of carapace) and there was a 3.9:1 female-to-male bias, consistent with limited data for this location two decades earlier. Only juvenile logger- heads ≤75.0 cm possessed haplotypes other than CC-A01 or CC-A02 that dominate in the region. Six rare and one un-described haplotype were pre-dominantly found in June 2004. [ABSTRACT FROM AUTHOR]