Publication Abstract

The migratory behaviour of juvenile Atlantic salmon

The migratory behaviour of juvenileAtlantic salmon

J.E. Thorpe and A. Moore

Migration is a fundamentalbiological response to adversity. Salmon (Salmo salar) move progressively fromone habitat to another as a habitat ceases to satisfy their changing needs. Hatching fromthe egg into the gravel redd, emerging from the redd onto the stream bed, moving away toestablish a feeding territory, moving downstream to deeper water over winter, and finallyemigrating from freshwater to sea - all these are abandonments of habitats once they canno longer satisfy the salmonsi needs. The downstream migration of smolting fish isinterpreted chiefly as the eviction of an organism which is losing freshwater adaptation,involving physiological, behavioral and morphological components. Final passage throughthe estuary is complicated by rhythmical tidal current reversal and salinity increase, andtemperature conditions modify the diel pattern of activity. Because the evolutionarilyrefined timing of arrival in the sea is critical for smolting salmon at any one rivermouth, the construction of estuarine barrages poses serious problems for the maintenanceof viable salmon populations in those rivers.

Reference:

J.E. Thorpe and A. Moore, 1997. The migratory behaviour of juvenile Atlantic salmon. pp.15-22, In: Third Workshop of the Japanese Association of Salmonid Science: SalmonMigration and Their Enhancement, Sapporo, Japan, (In Japanese).

J.E. Thorpe and A. Moore*

pp. 15-22, In: Third Workshop of the Japanese Association of Salmonid Science: Salmon Migration and Their Enhancement, Sapporo, Japan, (In Japanese).