Physical and behavioural influences on larval fish retention: contrasting patterns in two Antarctic fishes
Physical and behavioural influences on larval fish retention: contrasting patterns in two Antarctic fishes
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DOI：
10.3354/meps09908
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发表时间：
2012-09
影响因子：
2.5
通讯作者：
E. Young;J. Rock;M. Meredith;M. Belchier;E. Murphy;G. Carvalho
中科院分区：
文献类型：
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作者：
E. Young;J. Rock;M. Meredith;M. Belchier;E. Murphy;G. Carvalho
南乔治亚岛周围的水域是南大洋中最多产的水域之一，支持着国际上重要的渔业。然而，鱼类种群存在显著的年际变化，一些物种未能从历史上的过度捕捞中恢复过来。浮游生物鱼卵和幼体的扩散和滞留对维持成鱼种群起着关键作用。我们使用数值模拟方法研究了海洋学和生活史变化对2种南极鱼类：Champsocephalus gunnari（鲭鱼冰鱼）和Notothenia rossii（大理石纹岩鳕鱼）扩散和保留的影响。结果表明，罗氏夜蛾幼虫的平均滞留量为5.3%，显著低于贡纳利夜蛾（31.3%），其差异与贡纳利夜蛾浮游周期较长有关。这种明显的幼虫在当地招募地的损失可能是导致北蛾种群未能从20世纪70年代的崩溃中恢复过来的原因。然而，两种植物的保留率均表现出较高的年际变化。产卵地点对贡纳利梭菌的扩散和滞留有强烈的影响，其中西南南乔治亚大陆架产卵地点对总体滞留的贡献最大。此外，C. gunnari的一个一致特征是在邻近的南乔治亚和Shag Rocks陆架之间缺乏幼虫交换，两者之间的距离仅为240 km。我们的研究结果为南乔治亚州贡纳瑞氏线虫和罗西氏线虫种群的人口动态和连通性提供了见解，并与该地区的恢复前景和对环境变异性和变化的持续响应有关。
Waters around South Georgia are amongst the most productive in the Southern Ocean, and support internationally important fisheries. However, there is significant inter-annual variability in fish stocks, and some species have failed to recover from historical overfishing. Dispersal and retention of the planktonic eggs and larvae of marine fish can play a key role in the maintenance of adult stocks. We use a numerical modelling approach to examine the influence of oceanographic and life-history variability on the dispersal and retention of 2 Antarctic fishes: Champsocephalus gunnari (mackerel icefish) and Notothenia rossii (marbled rockcod). Mean retention of N. rossii larvae was predicted to be 5.3%, considerably lower than that of C. gunnari (31.3%), a difference related to the longer planktonic period of the former. Such apparent loss of larvae from local recruitment grounds may contribute to the failure of the N. rossii population to recover from its collapse in the 1970s. However, retention of both species showed high inter-annual variability. Dispersal and retention of C. gunnari were strongly influenced by location of the spawning site, with the greatest contribution to overall retention from spawning sites on the southwest South Georgia shelf. In addition, a consistent feature in C. gunnari was a lack of larval exchange between the proximate South Georgia and Shag Rocks shelves, regions separated by only 240 km. Our findings provide insights into the demographic dynamics and connectivity of C. gunnari and N. rossii populations at South Georgia in relation to prospects for recovery and ongoing responses to environmental variability and change in the region.