Early life history traits and geographical distribution of Parachaenichthys charcoti
Early life history traits and geographical distribution of Parachaenichthys charcoti
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DOI：
10.1017/s0954102017000189
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发表时间：
2017-05
影响因子：
1.6
通讯作者：
M. La Mesa;E. Riginella;Christopher D. Jones
中科院分区：
文献类型：
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作者：
M. La Mesa;E. Riginella;Christopher D. Jones
摘要该属的两个种的地理分布是异地的，仅限于南乔治亚州-南桑威奇群岛(P.georgianus)和南奥克尼群岛-南设得兰群岛(P.charcoti)的内陆架。利用矢状耳石对布兰斯菲尔德海峡冬季和夏季幼体的生长速度和出海历时进行了测定，以评价其成虫分布地理格局与早期生活史特征的一致性。个体年龄是通过微增量计数来确定的，假设它们是每日增量。Gompertz模型与年龄长度估计值吻合，28-204日龄个体的平均增长率为0.22 mm day-1。幼虫孵化的时间相对较长，从7月一直持续到9月。根据幼体和幼体的年龄数据，查尔科蒂对虾的远洋幼虫历期约为6个月，与南乔治亚州的杰氏对虾一样。幼虫对近岸生境的强烈依赖可能会阻碍它们在大空间范围内的扩散，限制了远距离种群之间的联系，为解释这两个物种目前的地理分布提供了线索。
Abstract The geographical distribution of the two species of the genus Parachaenichthys is allopatric and restricted to the inner shelves of South Georgia–South Sandwich Islands (P. georgianus) and South Orkney Islands–South Shetland Islands (P. charcoti). To evaluate the consistency between the geographical patterns of adult distribution and early life history traits of P. charcoti, sagittal otoliths were used to estimate growth rate and pelagic duration in larvae and juveniles of this species collected in the Bransfield Strait in winter and summer, respectively. Individual age was determined through microincrement counts, assuming they were daily increments. The Gompertz model was fitted to age–length estimates, providing a mean growth rate of 0.22 mm day-1 estimated for 28–204-day-old individuals. Larval hatching was spread over a relatively wide period, lasting from July throughout September. The pelagic larval duration of P. charcoti was about six months based on ageing data of larvae and juveniles, as reported for P. georgianus from South Georgia. The strong dependence of larvae on the inshore habitat may hamper their dispersal at large spatial scale limiting the connectivity among distant populations, providing clues to interpret the present geographical distribution of the two species.