The Whitney Laboratory for Marine Bioscience, Department of Biology, University of Florida, 9505 Oceanshore Blvd, St Augustine, FL 32080, USA.
Hawaii Institute of Marine Biology, University of Hawaii, Manoa, HI 96744, USA.
J Exp Biol. 2020 Jun 26;223(Pt 12):jeb220962. doi: 10.1242/jeb.220962.
To forage in fast, turbulent flow environments where prey is abundant, fishes must deal with the high associated costs of locomotion. Prevailing theory suggests that many species exploit hydrodynamic refuges to minimize the cost of locomotion while foraging. Here, we challenge this theory based on direct oxygen consumption measurements of drift-feeding trout () foraging in the freestream and from behind a flow refuge at velocities up to 100 cm s We demonstrate that refuging is not energetically beneficial when foraging in fast flows because of a high attack cost and low prey capture success associated with leaving a station-holding refuge to intercept prey. By integrating optimum foraging theory with empirical data from respirometry and video tracking, we developed a mathematical model to predict when drift-feeding fishes should exploit or avoid refuges based on prey density, size and flow velocity. Our optimum foraging and refuging model provides new mechanistic insights into locomotor costs, habitat use and prey choice of fish foraging in current-swept habitats.
为了在猎物丰富的快速动荡的流动环境中觅食，鱼类必须应对与运动相关的高成本。流行的理论表明，许多物种利用水动力避难所来最小化觅食时的运动成本。在这里，我们根据在高达 100 cm/s 的速度下，在主流和水流避难所后面漂流觅食的鳟鱼 () 的直接耗氧量测量，对这一理论提出了挑战。我们证明，由于离开一个驻留点避难所去拦截猎物的高攻击成本和低猎物捕获成功率，在快速流动中避难所觅食并不能带来能量上的好处。通过将最优觅食理论与呼吸计和视频跟踪的经验数据相结合，我们开发了一个数学模型，根据猎物密度、大小和流速来预测漂流觅食的鱼类何时应该利用或避免避难所。我们的最优觅食和避难所模型为在水流冲刷的栖息地中觅食的鱼类的运动成本、栖息地利用和猎物选择提供了新的机械洞察力。
