Shifting control of recruitment of walleye pollock Theragra chalcogramma after a major climatic and ecosystem change
Shifting control of recruitment of walleye pollock Theragra chalcogramma after a major climatic and ecosystem change
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DOI：
10.3354/meps198215
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发表时间：
2000-01-01
影响因子：
2.5
通讯作者：
Bailey, KM
中科院分区：
文献类型：
--
作者：
Bailey, KM
在生活史的walleye狭鳕Theragra chalcogramma在很大程度上决定招聘的关键阶段已经转移到阿拉斯加湾人口。这一变化是在20世纪70年代末发生重大环境制度转变以及随后长寿的掠食性比目鱼和鳕鱼在生态系统中占据主导地位之后发生的。构建了一个探索性生命表的阶段特定丰度的数据，以分析人口统计学的十年尺度变化。在1980年代中期之前，补充与幼虫死亡率相关，这在很大程度上受到环境条件的影响。20世纪80年代中期后，幼虫死亡率/招聘关系侵蚀，并有一个趋势，更大的少年死亡率与捕食性比目鱼和鳕鱼的丰度增加相吻合。近年来，对补充的控制似乎已从对幼虫的环境影响转向对少年的生物控制。在评价鱼类种群动态的基本机制时，需要考虑生态系统变化和制度状况。
The critical stage in the life history of walleye pollock Theragra chalcogramma at which recruitment is largely determined has shifted in the Gulf of Alaska population. This change follows a major environmental regime-shift in the late 1970s and subsequent dominance of the ecosystem by long-lived predatory flatfishes and cod. An exploratory life table of data on stage-specific abundances was constructed to analyze decadal-scale changes in population demographics. Prior to the mid-1980s, recruitment was correlated with larval mortality, which was largely influenced by environmental conditions. After the mid-1980s, the larval mortality/recruitment relationship eroded, and there was a trend for greater juvenile mortality coinciding with an increase in the abundance of predatory flatfishes and cod. Control of recruitment appears to have shifted in recent years from environmental effects on larvae to biological control of juveniles. Ecosystem change and regime status need to be considered when evaluating mechanisms underlying fish-population dynamics.