McCormick Mark I
School of Marine Biology and Aquaculture, James Cook University, Townsville, Queensland, Australia.
Ecology. 2006 May;87(5):1104-9. doi: 10.1890/0012-9658(2006)87[1104:mmclts]2.0.co;2.
Most marine populations are sustained by the entry of juveniles that have survived the larval phase, during which time most die. The number of survivors depends strongly on the quality of the eggs produced by spawning females, but it is not known how the social conditions under which breeding occurs influence the quality of larvae produced. Here I show that the density of females interacting with breeding mothers directly influences the size of larvae produced, through a stress-related mechanism. On the Great Barrier Reef of Australia, breeding pairs of a damselfish, Pomacentrus amboinensis, were isolated on habitat patches, and additional females that could not access the spawning site were added at four densities (0, 1, 3, or 6 females). Additional females increased aggressive interactions by mothers and increased the levels of the stress hormone, cortisol, in their ovaries, leading to reduced larval size. Neither egg output nor yolk size of the larvae was influenced by female density. Pairs breeding in isolation produced the largest larvae; current theory suggests that these larvae should contribute most to subsequent population replenishment events. This social mechanism may influence which females effectively contribute to the next generation and may promote resilience in patchy or isolated populations.
大多数海洋种群靠度过幼体阶段存活下来的幼鱼的加入得以维持，而在幼体阶段大多数幼鱼会死亡。存活者的数量很大程度上取决于产卵雌鱼所产鱼卵的质量，但尚不清楚繁殖时的社会条件如何影响所产幼体的质量。在此我表明，与繁殖雌鱼互动的雌鱼密度通过一种与压力相关的机制直接影响所产幼体的大小。在澳大利亚大堡礁，将一对繁殖的雀鲷（安汶雀鲷）隔离在栖息地斑块上，并以四种密度（0、1、3或6只雌鱼）添加无法进入产卵地点的额外雌鱼。额外的雌鱼增加了雌鱼母亲的攻击性行为，并提高了其卵巢中应激激素皮质醇的水平，导致幼体尺寸减小。雌鱼密度对鱼卵产量和幼体的卵黄大小均无影响。单独繁殖的配对产出的幼体最大；当前理论认为，这些幼体对后续种群补充事件的贡献应该最大。这种社会机制可能会影响哪些雌鱼能有效地为下一代做出贡献，并可能促进零散或孤立种群的恢复力。
