title: Signature of ocean warming in global fisheries catch.
abstract: Marine fishes and invertebrates respond to ocean warming through distribution shifts, generally to higher latitudes and deeper waters. Consequently, fisheries should be affected by 'tropicalization' of catch (increasing dominance of warm-water species). However, a signature of such climate-change effects on global fisheries catch has so far not been detected. Here we report such an index, the mean temperature of the catch (MTC), that is calculated from the average inferred temperature preference of exploited species weighted by their annual catch. Our results show that, after accounting for the effects of fishing and large-scale oceanographic variability, global MTC increased at a rate of 0.19 degrees Celsius per decade between 1970 and 2006, and non-tropical MTC increased at a rate of 0.23 degrees Celsius per decade. In tropical areas, MTC increased initially because of the reduction in the proportion of subtropical species catches, but subsequently stabilized as scope for further tropicalization of communities became limited. Changes in MTC in 52 large marine ecosystems, covering the majority of the world's coastal and shelf areas, are significantly and positively related to regional changes in sea surface temperature. This study shows that ocean warming has already affected global fisheries in the past four decades, highlighting the immediate need to develop adaptation plans to minimize the effect of such warming on the economy and food security of coastal communities, particularly in tropical regions.
authors.affiliation: Changing Ocean Research Unit, Fisheries Centre, The University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada. w.cheung@fisheries.ubc.ca
authors.forename: William W L
authors.initials: WW
authors.lastname: Cheung
authors.forename: Reg
authors.initials: R
authors.lastname: Watson
authors.forename: Daniel
authors.initials: D
authors.lastname: Pauly
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D003247:Conservation of Natural Resources / Q000706:statistics & numerical data; D017753:Ecosystem; D005398:Fisheries / Q000191:economics / Q000266:history / Q000706:statistics & numerical data*; D005399:Fishes / Q000145:classification* / Q000502:physiology*; D005523:Food Supply / Q000706:statistics & numerical data; D062305:Geographic Mapping; D057232:Global Warming / Q000191:economics / Q000266:history / Q000517:prevention & control / Q000706:statistics & numerical data*; D049673:History, 20th Century; D049674:History, 21st Century; D038622:Internationality; D009792:Oceans and Seas; D011157:Population Dynamics; D012623:Seawater; D013045:Species Specificity; D013696:Temperature; D014329:Tropical Climate