title: Changing recruitment capacity in global fish stocks.
abstract: Marine fish and invertebrates are shifting their regional and global distributions in response to climate change, but it is unclear whether their productivity is being affected as well. Here we tested for time-varying trends in biological productivity parameters across 262 fish stocks of 127 species in 39 large marine ecosystems and high-seas areas (hereafter LMEs). This global meta-analysis revealed widespread changes in the relationship between spawning stock size and the production of juvenile offspring (recruitment), suggesting fundamental biological change in fish stock productivity at early life stages. Across regions, we estimate that average recruitment capacity has declined at a rate approximately equal to 3% of the historical maximum per decade. However, we observed large variability among stocks and regions; for example, highly negative trends in the North Atlantic contrast with more neutral patterns in the North Pacific. The extent of biological change in each LME was significantly related to observed changes in phytoplankton chlorophyll concentration and the intensity of historical overfishing in that ecosystem. We conclude that both environmental changes and chronic overfishing have already affected the productive capacity of many stocks at the recruitment stage of the life cycle. These results provide a baseline for ecosystem-based fisheries management and may help adjust expectations for future food production from the oceans.
authors.affiliation: Department of Biology, Dalhousie University, Halifax, NS, Canada, B3H 4R2; Department of Earth System Science, University of California, Irvine, CA 92697; gbritten@uci.edu.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Britten
authors.affiliation: Department of Mathematics and Statistics, Dalhousie University, Halifax, NS, Canada, B3H 4R2.
authors.forename: Michael
authors.initials: M
authors.lastname: Dowd
authors.affiliation: Department of Biology, Dalhousie University, Halifax, NS, Canada, B3H 4R2;
authors.forename: Boris
authors.initials: B
authors.lastname: Worm
mesh_terms: D000818:Animals; D018533:Biomass; D002734:Chlorophyll / Q000378:metabolism; D057231:Climate Change; D005398:Fisheries / Q000379:methods*; D005399:Fishes / Q000254:growth & development*; D008018:Life Cycle Stages; D009792:Oceans and Seas; D010839:Phytoplankton / Q000254:growth & development / Q000378:metabolism; D011157:Population Dynamics
chemical_list: D002734:Chlorophyll
keywords: fisheries; nonstationary processes; population dynamics; productivity; recruitment