Seasonal Variability in Morphology of Blue Crab, Callinectes sapidus, Megalopae and Early Juvenile Stage Crabs, and Distinguishing Characteristics Among Co-Occurring Portunidae
Seasonal Variability in Morphology of Blue Crab, Callinectes sapidus, Megalopae and Early Juvenile Stage Crabs, and Distinguishing Characteristics Among Co-Occurring Portunidae
复制标题
蓝蟹、Callinectes sapidus、大眼蟹和幼蟹早期形态的季节变化以及共生梭子蟹科的区分特征
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
R. Forward
中科院分区：
文献类型：
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作者：
M. Ogburn;K. C. Stuck;R. Heard;Shiao Y Wang;R. Forward
摘要 具有重要商业价值的蓝蟹 Callinectes sapidus 数量的下降促使渔业管理者寻找新的管理策略。评估巨眼类或幼体早期阶段的年级强度可能有助于这项工作，但在许多地区，与共生物种分离是很困难的，因为形态特征随季节变化，并且已发表的描述不能充分区分 C. sapidus 与 C. similis 和其他相关物种。每月收集Callinectes sapidus和C. similis megalopae并在实验室培养至可以进行阳性鉴定的大小。对这两个物种的完整巨眼和早期蟹蜕的测量揭示了季节差异，春季巨眼比秋季巨眼具有更大的甲壳、更长的头刺和触角以及一些口部的刚毛更多。通过检查从 MS (1976-1979) 和 NC (2005) 沿海水域收集的样本，验证了形态变异的这种季节性模式。 NC大眼的吻部长度、背甲总长度以及吻部长度占背甲总长度的百分比与采集前2-4周的水温呈负相关。 Callinectes sapidus 和 C. similis megalopae 可以在地点和季节内通过以下因素快速区分：1）前外侧背甲边缘的形状，2）吻部长度占背甲总长度的百分比，以及 3）触角远端八节的总长度。这种快速分离对于需要识别大量个体的渔业研究至关重要。无论季节如何，分子分析或更详细的形态学分析对于最终分离仍然是必要的。编制了常见沿海梭子蟹和第一蟹阶段的关键信息，以帮助研究人员将梭子蟹和早期幼体阶段与同时存在的梭子蟹分开。
Abstract Declines in abundance of the commercially important blue crab Callinectes sapidus have led fishery managers to search for new management strategies. Assessing year-class strength at megalopal or early juvenile stages may contribute to this effort, but separation from co-occurring species is difficult in many areas because morphological characteristics vary with season and published descriptions do not adequately distinguish C. sapidus from C. similis and other related species. Callinectes sapidus and C. similis megalopae were collected monthly and cultured in the laboratory to a size at which positive identification could be made. Measurements on intact megalopae and early crab exuviae of both species revealed seasonal differences, with spring megalopae having larger carapaces, longer rostral spines and antennae and more setae on some mouth parts than fall megalopae. This seasonal pattern of morphological variability was verified through examination of samples collected from MS (1976–1979) and NC (2005) coastal waters. Rostrum length, total carapace length and rostrum length as a percent of total carapace length of NC megalopae were negatively correlated with water temperature 2–4 weeks prior to collection. Callinectes sapidus and C. similis megalopae can be rapidly separated within locations and seasons by: 1) the shape of the antero-lateral carapace margin, 2) rostral length as a percent of total carapace length, and 3) the combined length of the distal eight segments of the antenna. Such rapid separation is essential for fisheries studies requiring identification of large numbers of individuals. Molecular analyses or more detailed morphological analyses remain necessary for definitive separation regardless of season. Keys to common coastal portunid megalopae and first crab stages were compiled to aid investigators in separating C. sapidus megalopae and early juvenile stages from co-occurring portunids.