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Declines in body size of sockeye salmon associated with increased competition in the ocean

Declining body sizes have been documented for several species of Pacific salmon; however, whether size declines are caused mainly by ocean warming or other ecological factors, and whether they result primarily from trends in age at maturation or changing growth rates remain poorly understood. We qua...

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Autores principales: Ohlberger, Jan, Cline, Timothy J., Schindler, Daniel E., Lewis, Bert
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9904942/
https://www.ncbi.nlm.nih.gov/pubmed/36750195
http://dx.doi.org/10.1098/rspb.2022.2248
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author Ohlberger, Jan
Cline, Timothy J.
Schindler, Daniel E.
Lewis, Bert
author_facet Ohlberger, Jan
Cline, Timothy J.
Schindler, Daniel E.
Lewis, Bert
author_sort Ohlberger, Jan
collection PubMed
description Declining body sizes have been documented for several species of Pacific salmon; however, whether size declines are caused mainly by ocean warming or other ecological factors, and whether they result primarily from trends in age at maturation or changing growth rates remain poorly understood. We quantified changes in mean body size and contributions from shifting size-at-age and age structure of mature sockeye salmon returning to Bristol Bay, Alaska, over the past 60 years. Mean length declined by 3%, corresponding to a 10% decline in mean body mass, since the early 1960s, though much of this decline occurred since the early 2000s. Changes in size-at-age were the dominant cause of body size declines and were more consistent than trends in age structure among the major rivers that flow into Bristol Bay. Annual variation in size-at-age was largely explained by competition among Bristol Bay sockeye salmon and interspecific competition with other salmon in the North Pacific Ocean. Warm winters were associated with better growth of sockeye salmon, whereas warm summers were associated with reduced growth. Our findings point to competition at sea as the main driver of sockeye salmon size declines, and emphasize the trade-off between fish abundance and body size.
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spelling pubmed-99049422023-02-09 Declines in body size of sockeye salmon associated with increased competition in the ocean Ohlberger, Jan Cline, Timothy J. Schindler, Daniel E. Lewis, Bert Proc Biol Sci Biological Applications Declining body sizes have been documented for several species of Pacific salmon; however, whether size declines are caused mainly by ocean warming or other ecological factors, and whether they result primarily from trends in age at maturation or changing growth rates remain poorly understood. We quantified changes in mean body size and contributions from shifting size-at-age and age structure of mature sockeye salmon returning to Bristol Bay, Alaska, over the past 60 years. Mean length declined by 3%, corresponding to a 10% decline in mean body mass, since the early 1960s, though much of this decline occurred since the early 2000s. Changes in size-at-age were the dominant cause of body size declines and were more consistent than trends in age structure among the major rivers that flow into Bristol Bay. Annual variation in size-at-age was largely explained by competition among Bristol Bay sockeye salmon and interspecific competition with other salmon in the North Pacific Ocean. Warm winters were associated with better growth of sockeye salmon, whereas warm summers were associated with reduced growth. Our findings point to competition at sea as the main driver of sockeye salmon size declines, and emphasize the trade-off between fish abundance and body size. The Royal Society 2023-02-08 2023-02-08 /pmc/articles/PMC9904942/ /pubmed/36750195 http://dx.doi.org/10.1098/rspb.2022.2248 Text en © 2023 The Authors. https://creativecommons.org/licenses/by/4.0/Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, provided the original author and source are credited.
spellingShingle Biological Applications
Ohlberger, Jan
Cline, Timothy J.
Schindler, Daniel E.
Lewis, Bert
Declines in body size of sockeye salmon associated with increased competition in the ocean
title Declines in body size of sockeye salmon associated with increased competition in the ocean
title_full Declines in body size of sockeye salmon associated with increased competition in the ocean
title_fullStr Declines in body size of sockeye salmon associated with increased competition in the ocean
title_full_unstemmed Declines in body size of sockeye salmon associated with increased competition in the ocean
title_short Declines in body size of sockeye salmon associated with increased competition in the ocean
title_sort declines in body size of sockeye salmon associated with increased competition in the ocean
topic Biological Applications
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9904942/
https://www.ncbi.nlm.nih.gov/pubmed/36750195
http://dx.doi.org/10.1098/rspb.2022.2248
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