Ontogenesis of rheotactic and optomotor responses of juvenile Atlantic salmon

• Published in: Aquaculture Vol. 168; no. 1; pp. 17 - 26
• Main Authors: Veselov, A.E, Kazakov, R.V, Sysoyeva, M.I, Bahmet, I.N
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.1998; Elsevier Sequoia S.A
• Subjects: Animal behavior; Animal migration; Atlantic salmon; Behaviour; Fish; Marine; Rheotaxis; Salmo salar; Smolting; Velocity; Water; Rheotaxis; Atlantic salmon; Behaviour; Salmo salar; Smolting
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/S0044-8486(98)00362-7

Rheotactic and optomotor responses have been used to describe the ontogenetic relationship between young Atlantic salmon and water velocity. Rheotaxis changes dynamically as the fish develop from alevins to parr and to smolts. Sensitivity to water velocity, and the ability to maintain station in a flow, increase as the fish develop, allowing the fish to occupy different microhabitats as the temperatures rise within 13–24°C during the summer. As the temperature drops below 10°C in the winter, the intensity of these responses decreases, and the fish hide in the substratum. Among parr, the rheotactic response results in local migration seasonally, and site retention in flowing habitats. At smolting, as the parr become pelagic, their rheotactic and optomotor sensitivities and their station holding abilities decrease, and with these decreases the tendency to group increases. The change in the rheotactic response results in the pelagic behaviour at smolting, and the successful downstream migration.