Harvest-induced evolution and effective population size

• Published in: Evolutionary Applications
• Main Authors: Kuparinen, Anna, Hutchings, Jeffrey A., Waples, Robin S.
• Other Authors: Environmental Sciences, Anna Kuparinen / Principal Investigator
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2016
• Subjects: contemporary evolution; fisheries management; life history evolution; population genetics - empirical; wildlife management; FISHERIES-INDUCED EVOLUTION; EXPLOITED FISH STOCKS; LIFE-HISTORY; OVERLAPPING GENERATIONS; GENETIC COMPENSATION; TEMPORAL-CHANGES; CONSEQUENCES; AGE; OVEREXPLOITATION; COMPONENTS; 1181 Ecology; evolutionary biology; atlantic cod
• Online Access: http://hdl.handle.net/10138/167624

Much has been written about fishery-induced evolution (FIE) in exploited species, but relatively little attention has been paid to the consequences for one of the most important parameters in evolutionary biology-effective population size (N-e). We use a combination of simulations of Atlantic cod populations experiencing harvest, artificial manipulation of cod life tables, and analytical methods to explore how adding harvest to natural mortality affects N-e, census size (N), and the ratio N-e/N. We show that harvest-mediated reductions in N-e are due entirely to reductions in recruitment, because increasing adult mortality actually increases the N-e/N ratio. This means that proportional reductions in abundance caused by harvest represent an upper limit to the proportional reductions in N-e, and that in some cases N-e can even increase with increased harvest. This result is a quite general consequence of increased adult mortality and does not depend on harvest selectivity or FIE, although both of these influence the results in a quantitative way. In scenarios that allowed evolution, N-e recovered quickly after harvest ended and remained higher than in the preharvest population for well over a century, which indicates that evolution can help provide a long-term buffer against loss of genetic variability. Peer reviewed