Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means
Mapping the spawning grounds of North Sea cod (Gadus morhua) by direct and indirect means
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DOI：
10.1098/rspb.2008.0201
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发表时间：
2008-07-07
影响因子：
4.7
通讯作者：
Wright, Peter J.
中科院分区：
文献类型：
--
作者：
Fox, Clive J.;Taylor, Martin;Wright, Peter J.
尽管最近有证据表明存在子种群结构，但北海鳕鱼被评估为一个单一的单位。因此，对子股趋势的了解很差。特别是，最近没有对哪些产卵地是活跃的进行评估。在这里，我们报告了第一次覆盖整个北海的浮游鱼调查结果。此外，2004年进行的这项调查首次广泛使用基于dna的分子方法来明确识别早期发育阶段的鳕鱼卵。我们将浮游生物调查的结果与同期拖网调查中从成熟鳕鱼分布推断的估计产蛋量进行比较。两种方法的结果基本一致，并显示出产蛋热点在多格尔滩的南部和东部边缘，在德国湾，马里湾和设得兰群岛的东部。这些区域大致与1940年至1970年间已知的产卵地点一致。然而，我们无法直接在弗朗伯勒（英格兰东北海岸）的历史产卵地检测到大量的鳕鱼卵。结果表明，北海大部分主要的鳕鱼产卵地仍然活跃，但一些局部种群可能已经减少到现在很难在浮游生物中发现卵的程度。
Despite recent evidence for sub-stock structuring, North Sea cod are assessed as a single unit. As a consequence, knowledge of sub-stock trends is poor. In particular, there are no recent evaluations of which spawning grounds are active. Here we report results from the first ichthyoplankton survey to cover the whole North Sea. Also, this survey, conducted in 2004, was the first to make extensive use of DNA-based molecular methods to unambiguously identify early developmental stage cod eggs. We compare the findings from the plankton survey with estimated egg production inferred from the distribution of mature cod in contemporaneous trawl surveys. Results from both approaches were in general agreement and showed hot spots of egg production around the southern and eastern edges of the Dogger Bank, in the German Bight, the Moray Firth and to the east of the Shetlands. These areas broadly coincide with known spawning locations from the period 1940 to 1970. We were, however, unable to directly detect significant numbers of cod eggs at the historic spawning ground off Flamborough (northeast coast of England). The results demonstrate that most of the major spawning grounds of cod in the North Sea are still active but that some localized populations may have been reduced to the point where it is now difficult to detect the presence of eggs in the plankton.