Effects of individual variation in length, condition and run‐time on return rates of wild‐reared Atlantic salmon Salmo salar smolts

Groups of wild‐reared Atlantic salmon Salmo salar smolts were captured during their seaward migration on a tributary of the River Conon, Scotland, U.K., from 1999 to 2014 and tagged with passive integrated transponders (PIT). Fish that subsequently returned to the river after growing at sea were rec...

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Bibliographic Details
Published in:Journal of Fish Biology
Main Authors: Armstrong, J. D., McKelvey, S., Smith, G. W., Rycroft, P., Fryer, R. J.
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2018
Subjects:
Online Access:http://dx.doi.org/10.1111/jfb.13548
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjfb.13548
https://onlinelibrary.wiley.com/doi/pdf/10.1111/jfb.13548
Description
Summary:Groups of wild‐reared Atlantic salmon Salmo salar smolts were captured during their seaward migration on a tributary of the River Conon, Scotland, U.K., from 1999 to 2014 and tagged with passive integrated transponders (PIT). Fish that subsequently returned to the river after growing at sea were recorded automatically by a PIT‐detector in a fish pass. Return rate was related directly to length and condition and inversely to day of the year that the smolt was tagged. Over years, as the study progressed, there was a significant increase in the proportion of smolts returning after two or more years at sea and no trend in returns of salmon having spent one winter at sea. There was no trend in the date of return of salmon across the study period. Fish that had spent more winters at sea returned earlier in the year.