Evol Ecol Res 16: 417-433 (2014)     Full PDF if your library subscribes.

Relative contributions of evolutionary and ecological dynamics to body size and life-history changes of herring (Clupea harengus) in the Bothnian Sea

Örjan Östman1, Olle Karlsson2, Jukka Pönni3, Olavi Kaljuste1, Teija Aho1 and Anna Gårdmark1

1Department of Aquatic Resources, Swedish University of Agricultural Sciences, Öregrund, Sweden,  2Department of Environmental Research and Monitoring, Swedish Museum of Natural History, Stockholm, Sweden and  3Natural Resources Institute Finland, Natural Resources and Bioproduction, Helsinki, Finland

Correspondence: Ö. Östman, Department of Aquatic Resources, Swedish University of Agricultural Sciences, Skolgatan 6, SE-742 42 Öregrund, Sweden.
e-mail: orjan.ostman@slu.se


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.

Keywords: Baltic Sea, density dependence, fisheries, grey seal, pelagic, zooplankton.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2014 Örjan Östman. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.