University of Wisconsin Center for Limnology, 680 N. Park Street, Madison, WI 53706, U.S.A.
J Fish Biol. 2011 Feb;78(2):449-65. doi: 10.1111/j.1095-8649.2010.02855.x.
Diel vertical migration (DVM) of young-of-the-year (YOY) herring Clupea harengus and one of their major predators, pikeperch Sander lucioperca, was examined using bottom-mounted hydroacoustics in Himmerfjärden, a brackish bay of the Baltic Sea, in summer. In contrast to previous studies on DVM of C. harengus aggregated across size and age classes, YOY C. harengus showed a reverse DVM trajectory, deeper at night and, on average, shallower during the day. This pattern was observed consistently on five acoustic sampling occasions in 3 years and was corroborated by two out of three trawl surveys. Large acoustic targets (target strength >-33 dB, probably piscivorous S. lucioperca >45 cm) showed a classic DVM trajectory, shallow at night and deeper during the day. Variability in YOY C. harengus vertical distribution peaked at dawn and dusk, and their vertical distribution at midday was distinctly bimodal. This reverse DVM pattern was consistent with bioenergetic model predictions for YOY C. harengus which have rapid gut evacuation rates and do not feed at night. Reverse DVM also resulted in low spatial overlap with predators.
使用底部安装的水声学技术，在波罗的海的一个半咸水湾——希默尔福丹夏季，研究了幼龄鲱鱼（Clupea harengus）和它们的主要捕食者之一——欧鳊（Sander lucioperca）的昼夜垂直迁移（DVM）。与之前关于鲱鱼在大小和年龄类群上聚集的 DVM 的研究相反，幼龄鲱鱼表现出相反的 DVM 轨迹，夜间较深，白天平均较浅。这一模式在 3 年内的 5 次声学采样中得到了一致的观察，并得到了 3 次拖网调查中的 2 次的证实。大型声学目标（目标强度>-33dB，可能是肉食性的欧鳊>45 厘米）表现出典型的 DVM 轨迹，夜间较浅，白天较深。幼龄鲱鱼垂直分布的变异性在黎明和黄昏时达到峰值，而它们在中午的垂直分布明显呈双峰型。这种反向 DVM 模式与幼龄鲱鱼的生物能量学模型预测一致，幼龄鲱鱼的肠道排空率很快，并且不在夜间进食。反向 DVM 还导致与捕食者的空间重叠度降低。
