Grossman Gary D
Department of Wildlife and Fisheries Biology, University of California at Davis, 95616, Davis, Ca, USA.
Oecologia. 1980 Jan;47(2):233-238. doi: 10.1007/BF00346826.
Two age classes (0+ to 3+ and 4+ to 7+) of bay gobies (Lepidogobius lepidus Girard) differed in the sizes of whole prey (except polychaetes) recovered from the digestive tract. Although older fish consumed greater amounts of larger prey they did not capture larger individuals of a given prey type for seven of nine prey classes. The remaining two, harpacticoid copepods and ostracods contribute minimally to ontogenetic differences. The switch to larger prey appears to either decrease exposure to predation through a reduction in foraging time or increase energy intake. This is facilitated through older fishes greater size and/or superiority in intraspecific competition. These differences can probably be viewed as adaptations to selective pressures imposed by fluctuating food resources on predation levels in bays and estuaries.
两个年龄组（0+至3+和4+至7+）的湾口虾虎鱼（Lepidogobius lepidus Girard）从消化道中回收的整个猎物（除多毛类外）大小存在差异。尽管年长的鱼消耗了更多更大的猎物，但在九个猎物类别中的七个类别中，它们并未捕获到给定猎物类型中更大的个体。其余两个类别，猛水蚤和介形虫对个体发育差异的贡献最小。转向更大的猎物似乎要么通过减少觅食时间来降低被捕食的风险，要么增加能量摄入。这通过年长鱼类更大的体型和/或种内竞争优势得以实现。这些差异可能被视为对海湾和河口食物资源波动对捕食水平施加的选择压力的适应。
