A1 Journal article – refereed
Life history variation across four decades in a diverse population complex of Atlantic salmon in a large subarctic river




List of Authors: Jaakko Erkinaro, Yann Czorlich, Panu Orell, Jorma Kuusela, Morten Falkegård, Maija Länsman, Henni Pulkkinen, Craig R. Primmer, Eero Niemelä
Publisher: CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS
Publication year: 2019
Journal: Canadian Journal of Fisheries and Aquatic Sciences
Journal name in source: CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
Journal acronym: CAN J FISH AQUAT SCI
Volume number: 76
Number of pages: 14
ISSN: 0706-652X

Abstract
We used over 154 000 scale samples collected from salmon fisheries in the large River Teno system over a 40-year period to quantify life history diversity and long-term trends. We identified 120 different life history strategies, including combinations of smolt (2-8) and sea ages (1-5) and previous spawning events. Most strategies were rare; 60% of individuals matured after 1 year at sea following 3-5 years in fresh water. Age at maturity changed with an increase in two-sea-winter salmon and previous spawners and a decline in three-sea-winter fish. Smolt age distribution showed a decreasing proportion of age-3 smolts, while that of age-5 smolts increased. Fishing gear and fishing season times selected for fish differing in life history strategies. Temporal variation in life histories reflected changes in both fisheries and the changing environment. There was an inverse relationship between years spent in fresh water and sea age. Biocomplexity was manifested by the multiple year classes (6-11) present in annual runs, which increased with years, reflecting an increase both in previous spawners and sampling effort. The high number of cohorts spawning simultaneously each year indicates strong generational overlap, which has been suggested to maintain genetic diversity and thereby resilience via the portfolio effect.


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Last updated on 2019-20-07 at 10:36

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