Variability in growth rates of juvenile fishes in different estuarine habitats
Variability in growth rates of juvenile fishes in different estuarine habitats
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不同河口生境幼鱼生长速率的差异
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发表时间：
1992
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通讯作者：
S. Sogard
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作者：
S. Sogard
河口是许多海洋鱼类的重要繁殖地。在最初的河口栖息期间，幼鱼可能会从快速生长中受益匪浅，这可以降低对尺寸选择性捕食者的敏感性。测量不同河口地点和栖息地生长率的变异程度。我在美国新泽西州河口的 4 个地点对 3 个物种（美洲拟侧盖虾、Tautoga onitis 和 Gobiosoma bosci）进行了笼养实验。两个地点位于有茂密鳗草大叶藻码头床的河口（小蛋港），另外两个地点位于缺乏鳗草但有大型藻类石莼斑片状堆积的河口（大湾）。实验在每个地点的植被（大叶藻或石莼）和无植被栖息地进行。在不同物种的实验中，4个地点之间以及2个栖息地之间的生长率的相对差异通常保持不变，这表明觅食价值的一致性。对于所有 3 个物种，大湾地点的生长速度最高，而蛋港小地点的生长速度通常最低。植被（大叶藻或石莼）的存在仅对甲沟炎的生长有利。观察到的水温、沉积物结构和食物供应模式是影响观察到的生长率差异的潜在因素。对 3 种鱼类的自然密度进行了量化，并与生长实验的结果进行比较，以确定快速生长与栖息地质量的其他属性之间是否存在权衡。 P. americanus 和 Tonitis 在支持较快生长的区域更为丰富，但未植被基质中完全没有 tautog 表明存在一定程度的栖息地回避。对于 G. bosci，栖息地选择和觅食质量之间存在明显的权衡；鳗草床内的虾虎鱼数量最多，而鳗草床的生长速度最差。
Estuaries are vital nursery grounds for many marine fishes. During initial estuarine residence, juvenile fishes presumably benefit greatly from rapid growth, which can diminish susceptibility to size-selective predators. To measure the degree of variability in growth rates across different estuarine sites and habitats. I conducted caging experiments with 3 species (Pseudopleuronectes americanus, Tautoga onitis, and Gobiosoma bosci) at 4 sites in New Jersey, USA, estuaries. Two sites were in an estuary with dense eelgrass Zostera marina beds (Little Egg Harbor) and 2 were in an estuary lacking eelgrass but supporting patchy accumulations of the macroalgae Ulva lactuca (Great Bay). Experiments were conducted in vegetated (either Zostera or Ulva) and unvegetated habitats at each site. Relative differences in growth rates among the 4 sites and between the 2 habitats were generally maintained across experiments withln species, suggesting a consistency in foraging value. For all 3 species, growth .was highest at a Great Bay site and generally lowest at a httle Egg Harbor site. The presence of vegetation (either Zostera or Ulva) was beneficial to growth only for T onitis. Observed patterns in water temperature, sediment structure, and food availability were potential factors effecting the observed differences in growth rates. Natural densities of the 3 fish species were quantified and compared to the results of growth experiments to determine if there were trade-offs between rapid growth and other attributes of habitat quality. P. americanus and T onitis were more abundant in areas supporting faster growth, but the complete absence of tautog from unvegetated substrates suggested some degree of habitat avoidance. A clear trade-off between habitat selection and foraging quality occurred for G. bosci; gobies were most abundant inside eelgrass beds, which supported the poorest growth rates.