Migration, Territoriality and Shoaling in Fishes

Abstract

Water movements range from the torrential discharges of mountain streams, the crash of waves against a rocky shore, the ebb and flow of the tide over a gently shelving beach to the slow moving currents of the oceans. Unless fish show active behavioural mechanisms to prevent it, they will be carried along with the water flow. Eggs, larvae and young juveniles either lack the mechanisms for active movement or those mechanisms are too poorly developed to prevent passive displacement. In these early stages in the life history, the movements of fish are largely determined by when and where the eggs are laid (chapter 6). As the locomotory capacity matures, fish become capable of resisting the water movements and can make active choices about the habitat in which they will live (chapters 2 and 3).