The Jonah crab Cancer borealis is a data‐poor species with an unknown stock status. They were historically caught as bycatch in American lobster Homarus americanus traps. The decline of the southern New England lobster stock since 1990 helped stimulate a targeted fishery and a sixfold increase in both the landings and ex‐vessel value of Jonah crab. Current knowledge on Jonah crab growth and reproduction is scarce and dated. Therefore, this research focused on updating fundamental biological information for Jonah crabs in the Middle Atlantic Bight. Morphometric analyses determined that male crabs reach size at 50% sexual maturity (SM₅₀) at 98.3 ± 1.4 mm carapace width (CW; ±95% CI), and female crabs reach SM₅₀ at 88.2 mm CW. These values are below the current minimum legal size. An increase in the proportion of female crabs in a new‐shell condition during the spring and summer months suggests a seasonal mating period. Expanding available information will substantiate accurate appointment of minimum legal sizes, minimize discard mortality, and increase understanding of stock dynamics, thus improving management and long‐term sustainability for the Jonah crab fishery.

中文翻译：

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大西洋中部约纳河蟹的成年雌蟹大小和壳状条件及形态关系

约拿蟹北方巨蟹是一种资料匮乏的物种，种群状况不明。从历史上看，它们是在美国龙虾美洲大螯虾陷阱中被兼捕的。自1990年以来，新英格兰南部龙虾种群的减少帮助刺激了有针对性的捕捞活动，并使乔纳蟹的上岸量和出口价值增加了​​六倍。关于乔纳蟹（Jonah）螃蟹生长和繁殖的最新知识很少而且过时。因此，本研究着重于更新中大西洋海岸线约拿蟹的基本生物学信息。形态计量学分析确定，雄蟹达到98.3±1.4毫米甲壳宽度（CW；±95％CI）时，性成熟度为50％（SM ₅₀），雌蟹达到SM ₅₀在88.2毫米CW。这些值低于当前的最小合法大小。在春季和夏季，处于新壳状态的雌蟹比例增加，表明是季节性交配期。扩大现有信息将证实对最小法定人数的准确任命，最大程度地减少了丢弃物的死亡率，并增加了对种群动态的了解，从而改善了约拿蟹渔业的管理和长期可持续性。