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首页> 外文期刊>Marine ecology progress series >Changes in California Chinook salmon diet over the past 50 years: relevance to the recent population crash
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Changes in California Chinook salmon diet over the past 50 years: relevance to the recent population crash

机译：过去50年里加州奇努克鲑鱼饮食的变化：与近期人口暴跌的相关性

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Salmon are affected by variation in ocean productivity; thus, improved understanding of mechanisms behind variability in ocean survival should help management of these ecologically and economically important populations. Based on a cooperative fisheries research program, we compared central California Chinook salmon Oncorhynchus tshawytscha adult food habits from spring and summer in the mid-2000s with historical records from 1955 and the 1980s. Diet diversity decreased through time, and was particularly low in May and June of the 2000s. Previously important prey, including juvenile rockfish Sebastes spp., krill Euphausiidae, Pacific herring Clupea pallesi and market squid Doryteuthis opalsecens, declined or disappeared from the diet, while Pacific sardine Sardinops sagax became very important prey in the 2000s; anchovy Engraulis mordax remained important throughout the study. Diet composition was correlated with regional mid-water trawls of prey abundance and also with local sea surface temperature (SST). Diet composition was related to the Sacramento Index of fall-run Chinook ocean abundance with a lag of 1 or 2 yr, and reflected the importance of prey availability during the second ocean year and smolt ocean-entry period, respectively. Spring is peak ocean entry for fall-run Chinook smolts, so declining prey diversity (specifically in May and June in the mid-2000s) may be related to recent population crashes. Seasonally, winter and fall diet data further demonstrated the significance of temporal variation in specific prey. This study highlights the importance of marine predator-prey interactions at an appropriate temporal resolution for understanding salmonid population dynamics.
机译：鲑鱼受海洋生产力变化的影响；因此，对海洋生存变异性背后的机制的更好理解应该有助于对这些具有生态和经济意义的种群进行管理。根据一项合作渔业研究计划，我们将2000年代中期春季和夏季加利福尼亚中部的奇努克鲑鱼Oncorhynchus tshawytscha的成年饮食习惯与1955年和1980年代的历史记录进行了比较。饮食多样性随时间下降，在2000年代的5月和6月特别低。以前重要的猎物，包括少年石斑鱼Sebastes spp。，磷虾Euphausiidae，太平洋鲱鱼Clupea pallesi和市场鱿鱼Doryteuthis opalsecens，在饮食中均已下降或消失，而太平洋沙丁鱼Sardinops sagax在2000年代成为非常重要的猎物。整个研究中，En鱼Engraulis mordax仍然很重要。饮食组成与猎物丰富的区域中水拖网以及当地海表温度（SST）相关。日粮组成与秋季运行的奇努克海丰度的萨克拉曼多指数相关，滞后时间为1或2年，分别反映了第二个大洋年和高寒期进入海洋期间猎物可利用性的重要性。春季是秋季的奇努克（Chinook）软体动物大洋进入的高峰，因此猎物多样性的下降（特别是2000年代中期的5月和6月）可能与最近的种群崩溃有关。从季节性上看，冬季和秋季的饮食数据进一步证明了特定猎物随时间变化的重要性。这项研究强调了在适当的时间分辨率下海洋捕食者与猎物之间的相互作用对于理解鲑鱼种群动态的重要性。

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