Crosby Sarah C, Raviraj Rebha, Fajardo Marisa, Susarchick Justin P, Romanello Domenic, Rowland Samantha M
Department of Conservation and Policy, The Maritime Aquarium at Norwalk, 10 N Water Street, Norwalk, CT, 06854, USA.
Sci Rep. 2025 Aug 27;15(1):31528. doi: 10.1038/s41598-025-14910-3.
Horseshoe crabs are an ancient species facing modern threats. While their importance to the conservation of endangered birds has garnered them increasing protections in recent years, disparate and insufficient management strategies across regions have precluded population recovery. Six datasets spanning 22-46 years for Atlantic horseshoe crabs (Limulus polyphemus) in the Long Island Sound, USA region were analyzed from regional monitoring programs conducted for general biodiversity assessments that had not been previously aggregated for the evaluation of this species. In these datasets, a decline of 2-9% per year in L. polyphemus count per sample was observed, with significant individual declines in 5 of the 6 datasets (all datasets from bays and harbors). The central Long Island Sound dataset exhibited a significantly slower rate of decline, driven by higher counts per sample in recent years, which should be monitored to determine if an improving trend will be sustained or if the recent higher counts were anomalies. An increasing proportion of females, mean prosomal width, and mean weight of L. polyphemus were also observed. With management activities at the local, regional, and national level impacting the potential for population recovery in this species, it is critical for policymakers at all levels to be aware of the severe decline in observations of this species across data sources, pointing to a need for urgent action to prevent local extinction.
鲎是一种面临现代威胁的古老物种。尽管近年来它们对濒危鸟类保护的重要性为其赢得了越来越多的保护，但各地区管理策略的差异和不足阻碍了种群数量的恢复。对美国长岛海峡大西洋鲎（美洲鲎）的六个数据集进行了分析，这些数据集跨度为22至46年，来自为一般生物多样性评估而开展的区域监测项目，此前未对这些数据进行汇总以评估该物种。在这些数据集中，每个样本中美洲鲎的数量每年下降2%至9%，六个数据集中有五个出现了显著的个体数量下降（所有来自海湾和港口的数据集）。长岛海峡中部数据集的下降速度明显较慢，这是由于近年来每个样本的数量较高，应对其进行监测，以确定这种改善趋势是否会持续，或者近期较高的数量是否属于异常情况。还观察到美洲鲎的雌性比例、头胸部平均宽度和平均体重都在增加。由于地方、区域和国家层面的管理活动影响该物种种群数量恢复的可能性，各级政策制定者必须意识到跨数据源观察到的该物种数量的严重下降，这表明需要采取紧急行动以防止其在当地灭绝。
