title: Marine Reserve Targets to Sustain and Rebuild Unregulated Fisheries.
abstract: Overfishing threatens the sustainability of coastal marine biodiversity, especially in tropical developing countries. To counter this problem, about 200 governments worldwide have committed to protecting 10%-20% of national coastal marine areas. However, associated impacts on fisheries productivity are unclear and could weaken the food security of hundreds of millions of people who depend on diverse and largely unregulated fishing activities. Here, we present a systematic theoretic analysis of the ability of reserves to rebuild fisheries under such complex conditions, and we identify maximum reserve coverages for biodiversity conservation that do not impair long-term fisheries productivity. Our analysis assumes that fishers have no viable alternative to fishing, such that total fishing effort remains constant (at best). We find that realistic reserve networks, which protect 10%-30% of fished habitats in 1-20 km wide reserves, should benefit the long-term productivity of almost any complex fishery. We discover a "rule of thumb" to safeguard against the long-term catch depletion of particular species: individual reserves should export 30% or more of locally produced larvae to adjacent fishing grounds. Specifically on coral reefs, where fishers tend to overexploit species whose dispersal distances as larvae exceed the home ranges of adults, decisions on the size of reserves needed to meet the 30% larval export rule are unlikely to compromise the protection of resident adults. Even achieving the modest Aichi Target 11 of 10% "effective protection" can then help rebuild depleted catch. However, strictly protecting 20%-30% of fished habitats is unlikely to diminish catch even if overfishing is not yet a problem while providing greater potential for biodiversity conservation and fishery rebuilding if overfishing is substantial. These findings are important because they suggest that doubling or tripling the only globally enforced marine reserve target will benefit biodiversity conservation and higher fisheries productivity where both are most urgently needed.
authors.affiliation: Marine Spatial Ecology Lab and Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.|School of Biological Sciences, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.
authors.forename: Nils C
authors.initials: NC
authors.lastname: Krueck
authors.affiliation: Oceans Program, World Wildlife Fund (WWF), Washington, D. C., United States of America.
authors.forename: Gabby N
authors.initials: GN
authors.lastname: Ahmadia
authors.affiliation: School of Biological Sciences, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.|Australian Research Council Centre of Excellence for Environmental Decisions, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.
authors.forename: Hugh P
authors.initials: HP
authors.lastname: Possingham
authors.affiliation: School of Biological Sciences, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Riginos
authors.affiliation: School of Biological Sciences, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.|School of BioSciences, The University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Treml
authors.affiliation: Marine Spatial Ecology Lab and Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.|School of Biological Sciences, The University of Queensland, St Lucia Campus, Brisbane, Queensland, Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Mumby
mesh_terms: D000818:Animals; D044822:Biodiversity; D003247:Conservation of Natural Resources; D005398:Fisheries; D005399:Fishes / Q000254:growth & development; D008386:Marine Biology