Evolution of age and length at maturation of Alaskan salmon under size‐selective harvest

Evolutionary Applications

Neala W. Kendall¹  Ulf Dieckmann²  Mikko Heino²  André E. Punt¹ 

[1] School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA;International Institute of Applied Systems Analysis, Laxenburg, Austria

关键词: fishery selection;    harvest‐induced evolution;    Oncorhynchus nerka;    phenotypic plasticity;    probabilistic maturation reaction norms;   

DOI  :  10.1111/eva.12123

来源: Wiley

【 摘 要 】

Abstract

Spatial and temporal trends and variation in life-history traits, including age and length at maturation, can be influenced by environmental and anthropogenic processes, including size-selective exploitation. Spawning adults in many wild Alaskan sockeye salmon populations have become shorter at a given age over the past half-century, but their age composition has not changed. These fish have been exploited by a gillnet fishery since the late 1800s that has tended to remove the larger fish. Using a rare, long-term dataset, we estimated probabilistic maturation reaction norms (PMRNs) for males and females in nine populations in two basins and correlated these changes with fishery size selection and intensity to determine whether such selection contributed to microevolutionary changes in maturation length. PMRN midpoints decreased in six of nine populations for both sexes, consistent with the harvest. These results support the hypothesis that environmental changes in the ocean (likely from competition) combined with adaptive microevolution (decreased PMRNs) have produced the observed life-history patterns. PMRNs did not decrease in all populations, and we documented differences in magnitude and consistency of size selection and exploitation rates among populations. Incorporating evolutionary considerations and tracking further changes in life-history traits can support continued sustainable exploitation and productivity in these and other exploited natural resources.

【 授权许可】

CC BY   
© 2013 The Authors. Evolutionary Applications published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.