title: Predator-driven intra-species variation in locomotion, metabolism and water velocity preference in pale chub (Zacco platypus) along a river.
abstract: Fish inhabit environments that vary greatly in terms of predation intensity, and these predation regimes are generally expected to be a major driver of divergent natural selection. To test whether there is predator-driven intra-species variation in the locomotion, metabolism and water velocity preference of pale chub (Zacco platypus) along a river, we measured unsteady and steady swimming and water velocity preference among fish collected from both high- and low-predation habitats in the Wujiang River. We also measured the routine metabolic rate (RMR), maximum metabolic rate (MMR) and cost of transport (COT) and calculated the optimal swimming speed (Uopt). The fish from the high-predation populations showed a shorter response latency, elevated routine metabolism, lower swimming efficiency at low swimming speed and lower water velocity preference compared with those from the low-predation populations. Neither of the kinematic parameters fast-start and critical swimming speed (Ucrit) showed a significant difference between the high- and low-predation populations. The fish from the high-predation populations may improve their predator avoidance capacity primarily through an elevated routine metabolism and shorter response latency to achieve advanced warning and escape, rather than an improved fast-start swimming speed or acceleration. Thus, the cost of this strategy is an elevated RMR, and no trade-off between unsteady and steady swimming performance was observed in the pale chub population under various predation stresses. It was interesting to find that the high-predation fish showed an unexpected lower velocity preference, which might represent a compromise between predation avoidance, foraging and energy saving.
authors.affiliation: College of Resources and Environmental Science, Key Laboratory of Southwest Resource Exploitation and Environmental Disaster Controlling Project of the Education Ministry, Chongqing University, Chongqing 400044, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Fu
authors.affiliation: College of Resources and Environmental Science, Key Laboratory of Southwest Resource Exploitation and Environmental Disaster Controlling Project of the Education Ministry, Chongqing University, Chongqing 400044, China Laboratory of Evolutionary Physiology and Behaviour, Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing 400047, China shijianfu9@hotmail.com.
authors.forename: Shi-Jian
authors.initials: SJ
authors.lastname: Fu
authors.affiliation: College of Resources and Environmental Science, Key Laboratory of Southwest Resource Exploitation and Environmental Disaster Controlling Project of the Education Ministry, Chongqing University, Chongqing 400044, China.
authors.forename: Xin-Zhong
authors.initials: XZ
authors.lastname: Yuan
authors.affiliation: Laboratory of Evolutionary Physiology and Behaviour, Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing 400047, China.
authors.forename: Zhen-Dong
authors.initials: ZD
authors.lastname: Cao
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D002681:China; D003530:Cyprinidae / Q000378:metabolism / Q000502:physiology*; D017753:Ecosystem; D004734:Energy Metabolism; D011235:Predatory Behavior; D045483:Rivers; D013550:Swimming / Q000502:physiology*; D014872:Water Movements
keywords: Critical swimming speed; Divergent natural selection; Fast-start escape response; Predation stress; Steady and unsteady swimming performance; Swimming efficiency