Behaviour of adult Atlantic salmon, Salmo salar L., in the estuary of the River Ribble in relation to variations in dissolved oxygen and tidal flow

• Published in: Journal of Fish Biology
• Main Authors: Priede, I. G., Solbé, J. F. de L. G., Nott, J. E., O'Grady, K. T., Cragg‐Hine, D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1988
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1988.tb05567.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1988.tb05567.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1988.tb05567.x

Twenty adult returning salmon were tracked in the estuary of the R. Ribble using acoustic oxygensensing transmitters during summer when a pronounced dissolved oxygen (DO) sag develops. Excluding two mortalities, 75% of these fish left the estuary to sea. Fish in the estuary moved to and fro with the tides over a 10 km amplitude experiencing cyclical changes in DO. Fish movement was inhibited below 40% of air saturation value (ASV) DO, and there was evidence of avoidance of DO below 55% ASV. The high rate of loss of fish to sea suggests that many of the fish in the estuary are non‐Ribble fish en route to other rivers. Adverse conditions in the Ribble therefore are likely to affect stocks in adjacent rivers.