The Behaviour of Migrating Pink and Chum Salmon Fry

• Published in: Journal of the Fisheries Research Board of Canada
• Main Author: Hoar, William S.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1956
• Subjects: General Medicine; Pink salmon
• Online Access: http://dx.doi.org/10.1139/f56-021; http://www.nrcresearchpress.com/doi/pdf/10.1139/f56-021

Pink salmon fry which have never schooled are negatively phototactic, prefer a cover of stones and do not emerge into bright light. Those which have schooled show a strong cover reaction when exposed to a rapid increase in light intensity but do not seek cover unless the change is abrupt. In general they remain in bright light after they have schooled. This change in behaviour occurs rapidly (15 minutes or less) when the fry school for the first time. Chum salmon fry establish a definite direction of swimming in the quiet water of a circular channel or basin. The established direction is stable and not permanently disturbed by light or darkness, by water currents, by strong avoiding reactions, by changing the location or by excluding direct skylight. The direction may be initially established in relation to water currents.