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The Atlantic brief squid, Lolliguncula brevis, is a euryhaline cephalopod that inhabits shallow, continental shelf habitats from Argentina to the Bay of Fundy. In the southeastern United States, brief squid can account for a considerable portion of the estuarine animal biomass and are an important component of the diets of species with high priority for management and conservation. Historical data from South Carolina Department of Natural Resources suggest that brief squid exhibit spatially and temporally variable size-frequency distributions within the Charleston Harbor estuary. Prior to this study, however, detailed life history information for this species was lacking in the region. Samples of brief squid were collected monthly at four stations along a salinity gradient within the Charleston Harbor estuary in 2019 to investigate temporal and spatial patterns of abundance, sex, size, and maturity. Season and station were significantly related to brief squid abundance, which was greater for all sexes in spring, summer, and fall than in winter. Catches of brief squid were dominated by immature squid compared with mature squid. Excluding sexually indistinct squid, and across all seasons, significantly more males were collected than females. Mean brief squid size tended to be larger in May than in several other months of the year, largely due to the lower abundance of small squid in that month. Logistic regression analyses indicated that brief squid size-at-maturity occurred at 50.2 mm for males and 59.2 mm for females. The presence of both small and large brief squid throughout the year at all stations supports a pattern of overlapping cohorts, whereas the continual presence of immature brief squid at all stations suggests asynchronous recruitment. This study provides valuable life history information that can be used to support the conservation and management of organisms that are either prey or predators of brief squid within the Charleston Harbor estuary. Further research over multiple years and within other estuaries in the Georgia Bight is needed, however, to determine how the life history patterns observed in this study apply more broadly across the region. [ABSTRACT FROM AUTHOR]

Wire‐mesh traps are extensively used to harvest blue crabs Callinectes sapidusbut 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 BRDdesigns 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 BRDsizes encompassing the range of BRDwidths and heights actually tested since 1992. Predictive relationships for trap entry or exclusion for each theoretical BRDsize were evaluated as a function of three geometric BRDattributes: BRDarea (cm2), diagonal BRDopening (cm), and the ratio of BRDwidth 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 BRDsize alone (slope = 0.28; 1,430 diamondback terrapins). Analyses also substantiated superior (i.e., >30% better) diamondback terrapin exclusion potential for a BRDwe designed that measured 5.1–6.4 cm (height) × 7.3 cm (width). Increasing the width of this BRDby 0.4 cm would also achieve a 99% capture probability for legal‐sized blue crabs, comparable to other widely tested and marketed BRDdesigns.

Five gear types were fished simultaneously to determine their efficacy at capturing premolt blue crabs Callinectes sapidus of commercial size (= 75 mm carapace width). Peeler pots, crab fykes, bush lines, habitat pots, and baited hard-crab pots deployed at each of nine stations (3 stations/area) in the Ashley River, South Carolina, were fished four consecutive days weekly from 18 April through 16 November 1979. Premolt crabs captured per gear-day (one unit of gear with a 24-hour soak time) were analyzed by 6-week intervals and area for each gear type. Hardcrab pots averaged more than 2.5 early premolt crabs per day during April and May, and habitat pots captured fewer, but consistent, numbers (0.7/day) of late premolt crabs from 18 April through 17 August. Modest peeler-pot success during April-May (over 0.5/gear-day) was attributed to the peak abundance of pubertal-molt females occurring prior to 18 April. Tidal amplitude (mean, 1.5 m) and current velocity (over 1.8 km/hour) limited the usefulness of bush lines and crab fykes throughout the study. Premolt male crabs outnumbered females 2.5:1, 1.6:1, and 1.3:1 in the habitat pot, peeler pot, and hard-crab pot, respectively. Overall, premolt crab catch rates declined from 1.0/gear-day during April-May to 0.4 in June-July, to 0.1 during October-November. Except for hard-crab pot catches during the first 6-week period, catch rates did not differ significantly among upper, middle, and lower river areas. Knowledgeable crabbers fishing habitat pots, peeler pots, and hard-crab pots in the most productive areas and seasons should capture premolt crabs at rates adequate to supply a shedding facility. A viable soft-shell crab industry in South Carolina would have little effect on the current fishery for hard crabs.

South Carolina's blue crab fishery is dominated by commercial landings, although an unknown but large number of recreational crabbers participate. Commercial landings of hard blue crabs average around 2.98 x IOs kg per year. Because of increasing fishing effort and value of blue crab meat, total annual value of the fishery has doubled in the last 5 years, approaching $5 million. Most of South Carolina's landings come from the trap fishery, with modest quantities also coming from trawl fisheries and mariculture. Catch rates in the fishery peak during fall, when most new recruits enter the fishery. Sponge crabs first appear in early April and are proportionally most abundant during summer, producing megalopae that enter the esturaries primarily during fall. Recent analyses of population montitoring data underscore theimportance of tidal creeks as nursery areas and refuges for mating blue crabs. Long-term fishery-independent indices of abundance (trawl and trap data) suggest that blue crab abundance is variable, but stocks seem to be relatively stable. We believe that rainfall (river discharge), disease, and possibly pollution have played varying roles in previous declines in stocks. A high correlation (r = 0.91) exists between annual license sales and commercial landings. suggesting that effort may be the limiting factor in annual harvests. South Carolina iscurrently assessing its blue crab fishery and examining such issues as limiting growth in fishing effort, quantification of fishing effort, under-reporting of catch, trap theft, vandalism of traps, ghost pots, competition between commercial and recreational crabbers, and conflicts with boaters. [ABSTRACT FROM AUTHOR]