Contrasting spawning temperature optima: Why are anchovy and sardine regime shifts synchronous across the North Pacific?
Contrasting spawning temperature optima: Why are anchovy and sardine regime shifts synchronous across the North Pacific?
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DOI：
10.1016/j.pocean.2008.03.008
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发表时间：
2008-05
影响因子：
4.1
通讯作者：
A. Takasuka;Y. Oozeki;H. Kubota;S. Lluch-Cota
中科院分区：
文献类型：
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作者：
A. Takasuka;Y. Oozeki;H. Kubota;S. Lluch-Cota
凤尾鱼和沙丁鱼都是丰富的小型中上层鱼类，在日本西部边界流区和加州东部边界流上升流区都表现出异相的种群振荡。这些物种交替可能表明近似同步的模式（生态系统之间的时间有一些变化），尽管在北太平洋的某些时期，至少直到最近的温度制度逆转。在这里，我们提出了一个对比模式的温度最佳之间的相对两侧的北太平洋的物种交替的同步阶段的一种可能的机制？根据卵和幼虫的发生与海面温度的关系，研究了日本鳀鱼（Engraulis）和日本沙丁鱼（Sardinops melanostictus）的最适产卵温度。这些分析是根据1978年至2004年在北太平洋西部进行的鱼卵和仔鱼调查的最新长期数据集（102 660次拖网）进行的。在0.1°C的温度间隔下，计算了这两个物种卵或幼虫阳性的浮游生物网样品与所有样品的相对频率比。该产卵温度指数超过1.0（最佳基线）从约。15至28°C，中间点为22°C，对于绵羊和约13-20°C，沙丁鱼在16-17°C有明显的峰值。产卵温度的模式清楚地显示了“温暖”和“广温”的日本和“凉爽”和“窄温”的日本沙丁鱼在西北太平洋。凤尾鱼和沙丁鱼之间的这种关系与早期发表的关于北方凤尾鱼（E. mordax）和加州沙丁鱼S. sagax）在加州海流系统中。最适产卵温度似乎是种特异性，而不是属特异性。相反的温度制度下的具体物种的温度最佳的鱼和沙丁鱼的反转可能提供了一个可能的理论解决方案，同步的鱼和沙丁鱼制度跨越北太平洋的转变。
Anchovy and sardine are both abundant small pelagic fish that have exhibited out-of-phase population oscillations in both the western boundary current region off Japan and the eastern boundary current upwelling region off California. These species alternations could indicate approximately synchronous patterns (with some variations in timing between ecosystems) despite the reversed temperature regimes for certain periods across the North Pacific, at least until recently. Here we suggest a contrasting pattern of temperature optima for anchovy and sardine spawnings between the opposite sides of the North Pacific as a possible mechanism of the synchronous phases of species alternations. Spawning temperature optima were examined for Japanese anchovy (Engraulis japonicus) and Japanese sardine (Sardinops melanostictus), based on occurrence of eggs and larvae in relation to sea surface temperature. The analyses were based on an updated long-term data set of egg and larval surveys from 1978 to 2004 (102,660 net tows) in the western North Pacific. The ratio of relative frequencies of plankton net samples that are positive for eggs or larvae versus all samples was calculated for temperature intervals of 0.1°C for both species. This spawning temperature index exceeded 1.0 (baseline for optimum) from ca. 15 to 28°C with a mid-point at 22°C for anchovy and ca. 13–20°C with a marked peak at 16–17°C for sardine. Patterns of spawning temperature clearly show “warm” and “eurythermal” Japanese anchovy and “cool” and “stenothermal” Japanese sardine in the western North Pacific. This relationship between anchovy and sardine showed a marked contrast to earlier published reports on the spawning temperature optima of northern anchovy (E. mordax) and California sardine (S. sagax) in the California Current system. The spawning temperature optimum appears to be species-specific rather than genus-specific. The reversed species-specific temperature optima of anchovy and sardine under the reversed temperature regimes could provide a possible theoretical solution to the synchronous anchovy and sardine regime shifts across the North Pacific.