Östman, Örjan
- Institutionen för akvatiska resurser (SLU Aqua), Sveriges lantbruksuniversitet
Question: What ecological and evolutionary processes are associated with the 25% decrease in age-specific body size of herring (Clupea harengus) in the Bothnian Sea over the last 30 years?Data: Four decades of data on length, age, and sexual maturity of individual herrings as well as environmental variables, including abundances of predators, prey and competitors, and estimates of fishing intensity/mortality from the Bothnian Sea.Search methods: Information-theoretic assessment of the relative influence of ecological and fisheries' effects on temporal changes in body growth. Probabilistic maturation reaction norms to study changes in age-specific size at maturation. Decomposition of trait variation into ecological and evolutionary contributions.Conclusions: Our evolutionary ecosystem perspective shows that both ecological and evolutionary processes are important contributors to observed phenotypic changes in this commercially exploited species. Around 60% of the decrease in age-specific body length can be attributed to increased density-dependent body growth. Evolutionary changes towards earlier maturation, owing to an indirect effect of size-selective mortality from grey seals and fisheries, account for a further 25% of the decrease in age-specific body size.
Baltic Sea; density dependence; fisheries; grey seal; pelagic; zooplankton
Evolutionary Ecology Research
2014, volym: 16, nummer: 5, sidor: 417-433
Utgivare: EVOLUTIONARY ECOLOGY LTD
Fisk- och akvakulturforskning
https://res.slu.se/id/publ/77139