title: Food web dynamics affect Northeast Arctic cod recruitment.
abstract: Proper management of ecosystems requires an understanding of both the species interactions as well as the effect of climate variation. However, a common problem is that the available time-series are of different lengths. Here, we present a general approach for studying the dynamic structure of such interactions. Specifically, we analyse the recruitment of the world's largest cod stock, the Northeast Arctic cod. Studies based on data starting in the 1970-1980s indicate that this stock is affected by temperature through a variety of pathways. However, the value of such studies is somewhat limited by the fact that they are based on a quite specific ecological and climatic situation. Recently, this stock has consisted of fairly young fish and the spawning stock has consisted of relatively few age groups. In this study, we develop a model for the effect of capelin (the cod's main prey) and herring on cod recruitment since 1973. Based on this model, we analyse data on cod, herring and temperature going back to 1921 and find that food-web effects explain a significant part of the cod recruitment variation back to around 1950.
authors.affiliation: Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1050, Blindern, 0316 Oslo, Norway.
authors.forename: Dag Ø
authors.initials: DØ
authors.lastname: Hjermann
authors.forename: Bjarte
authors.initials: B
authors.lastname: Bogstad
authors.forename: Anne Maria
authors.initials: AM
authors.lastname: Eikeset
authors.forename: Geir
authors.initials: G
authors.lastname: Ottersen
authors.forename: Harald
authors.initials: H
authors.lastname: Gjøsaeter
authors.forename: Nils Chr
authors.initials: NC
authors.lastname: Stenseth
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D005247:Feeding Behavior / Q000502:physiology*; D005398:Fisheries / Q000706:statistics & numerical data*; D020387:Food Chain; D048389:Gadus morhua / Q000254:growth & development*; D008962:Models, Theoretical; D036441:Osmeriformes; D013696:Temperature