Objective determination of the sea age of Atlantic salmon from the sizes and dates of capture of individual fish

P.J. Bacon, William Gurney, Edward Mckenzie, B. Whyte, R. Campbell, R. Laughton, G. Smith, J. MacLean

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The sea ages of Atlantic salmon indicate crucial differences between oceanic feeding zones that have important implications for conservation and management. Historical fishery-catch records go back more than 100 years, but the reliability with which they discriminate between sea-age classes is uncertain. Research data from some 188 000 scale-aged Scottish salmon that included size (length, weight) and seasonal date of capture on return to the coast were investigated to devise a means of assigning sea age to individual fish objectively. Two simple bivariate probability distributions are described that discriminate between 1SW and 2SW fish with 97% reliability, and between 2SW and 3SW fish with 70% confidence. The same two probability distributions achieve this accuracy across five major east coast Scottish rivers and five decades. They also achieve the same exactitude for a smaller recent dataset from the Scottish west coast, from the River Tweed a century ago (1894/1895), and for salmon caught by rod near the estuary. More surprisingly, they also achieve the same success for rod-caught salmon taken at beats remote from the estuary and including capture dates when some fish could have been in the river for a few months. The implications of these findings for fishery management and conservation are discussed.
LanguageEnglish
Pages130-143
Number of pages14
JournalICES Journal of Marine Science
Volume68
Issue number1
Early online date20 Sep 2010
DOIs
Publication statusPublished - 2010

Fingerprint

Salmo salar
salmon
probability distribution
fish
coasts
rivers
coast
estuaries
estuary
river
bycatch
fishery management
age class
fisheries management
age structure
fishery
fisheries
sea
distribution

Keywords

  • conservation
  • Salmo salar
  • stock management
  • temporal stability

Cite this

Bacon, P.J. ; Gurney, William ; Mckenzie, Edward ; Whyte, B. ; Campbell, R. ; Laughton, R. ; Smith, G. ; MacLean, J. / Objective determination of the sea age of Atlantic salmon from the sizes and dates of capture of individual fish. In: ICES Journal of Marine Science. 2010 ; Vol. 68, No. 1. pp. 130-143.
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Objective determination of the sea age of Atlantic salmon from the sizes and dates of capture of individual fish. / Bacon, P.J.; Gurney, William; Mckenzie, Edward; Whyte, B.; Campbell, R.; Laughton, R.; Smith, G.; MacLean, J.

In: ICES Journal of Marine Science, Vol. 68, No. 1, 2010, p. 130-143.

Research output: Contribution to journalArticle

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