title: Selective fishing induces density-dependent growth.
abstract: Over the last decades, views on fisheries management have oscillated between alarm and trust in management progress. The predominant policy for remedying the world fishing crisis aims at maximum sustainable yield (MSY) by adjusting gear selectivity and fishing effort. Here we report a case study on how striving for higher yields from the Eastern Baltic cod stock by increasing selectivity has become exceedingly detrimental for its productivity. Although there is a successive increase in numbers of undersized fish, growth potential is severely reduced, and fishing mortality in fishable size has increased. Once density-dependent growth is introduced, the process is self-enforcing as long as the recruitment remains stable. Our findings suggest that policies focusing on maximum yield while targeting greater sizes are risky and should instead prioritize catch rates over yield. Disregarding the underlying population structure may jeopardize stock productivity, with dire consequences for the fishing industry and ecosystem structure and function.
authors.affiliation: Department of Aquatic Resources, Institute of Marine Research, Swedish University of Agricultural Sciences, Turistgatan 5, SE-453 30 Lysekil, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Svedäng
authors.affiliation: 1] SIK-The Swedish Institute for Food and Biotechnology, Sustainable Food Production, Box 5401, SE-402 29 Göteborg, Sweden [2] Department of Biological and Environmental Sciences, University of Gothenburg, Box 461, SE-405 30 Göteborg, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Hornborg
mesh_terms: D000818:Animals; D017753:Ecosystem; D005398:Fisheries / Q000331:legislation & jurisprudence / Q000379:methods; D048389:Gadus morhua / Q000254:growth & development*; D009792:Oceans and Seas; D011156:Population Density