Voesenek Cees J, Muijres Florian T, van Leeuwen Johan L
Experimental Zoology Group, Wageningen University, PO Box 338, NL-6700 AH Wageningen, The Netherlands.
Experimental Zoology Group, Wageningen University, PO Box 338, NL-6700 AH Wageningen, The Netherlands
J Exp Biol. 2018 Jan 11;221(Pt 1):jeb149583. doi: 10.1242/jeb.149583.
Most larvae of bony fish are able to swim almost immediately after hatching. Their locomotory system supports several vital functions: fish larvae make fast manoeuvres to escape from predators, aim accurately during suction feeding and may migrate towards suitable future habitats. Owing to their small size and low swimming speed, larval fish operate in the intermediate hydrodynamic regime, which connects the viscous and inertial flow regimes. They experience relatively strong viscous effects at low swimming speeds, and relatively strong inertial effects at their highest speeds. As the larvae grow and increase swimming speed, a shift occurs towards the inertial flow regime. To compensate for size-related limitations on swimming speed, fish larvae exploit high tail beat frequencies at their highest speeds, made possible by their low body inertia and fast neuromuscular system. The shifts in flow regime and body inertia lead to changing functional demands on the locomotory system during larval growth. To reach the reproductive adult stage, the developing larvae need to adjust to and perform the functions necessary for survival. Just after hatching, many fish larvae rely on yolk and need to develop their feeding systems before the yolk is exhausted. Furthermore, the larvae need to develop and continuously adjust their sensory, neural and muscular systems to catch prey and avoid predation. This Review discusses the hydrodynamics of swimming in the intermediate flow regime, the changing functional demands on the locomotory system of the growing and developing larval fish, and the solutions that have evolved to accommodate these demands.
大多数硬骨鱼的幼体在孵化后几乎立即就能游泳。它们的运动系统支持多种重要功能：幼鱼会迅速做出动作以躲避捕食者，在吸食猎物时能精确瞄准，还可能向适宜的未来栖息地迁移。由于体型小且游泳速度低，幼鱼处于连接粘性流态和惯性流态的中间流体动力学状态。它们在低游泳速度时会经历相对较强的粘性效应，在最高速度时会经历相对较强的惯性效应。随着幼鱼生长并提高游泳速度，会向惯性流态转变。为了弥补与体型相关的游泳速度限制，幼鱼在最高速度时利用高尾摆频率，这得益于它们低的身体惯性和快速的神经肌肉系统。流态和身体惯性的变化导致幼鱼生长过程中对运动系统的功能需求不断改变。为了达到成年繁殖阶段，发育中的幼鱼需要适应并执行生存所需的功能。刚孵化后，许多幼鱼依靠卵黄，需要在卵黄耗尽前发育出摄食系统。此外，幼鱼需要发育并不断调整其感觉、神经和肌肉系统以捕食和躲避捕食。本综述讨论了中间流态下游泳的流体动力学、生长发育中的幼鱼运动系统不断变化的功能需求以及为适应这些需求而进化出的解决方案。
