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Modelling the effects of fishing on the biomass of the world's oceans from 1950 to 2006

Citation

Tremblay-Boyer, L and Gascuel, D and Watson, RA and Christensen, V and Pauly, D, Modelling the effects of fishing on the biomass of the world's oceans from 1950 to 2006, Marine Ecology Progress Series, 442 pp. 169-185. ISSN 0171-8630 (2011) [Refereed Article]

DOI: doi:10.3354/meps09375

Abstract

Marine fisheries have endured for centuries but the last 50 yr have seen a drastic increase in their reach and intensity. We generated global estimates of biomass for marine ecosystems and evaluated the effects that fisheries have had on ocean biomass since the 1950s. A simple and versatile ecosystem model was used to represent ecosystems as a function of energy fluxes through trophic levels (TLs). Using primary production, sea surface temperature, transfer efficiency, fisheries catch and TL of species, the model was applied on a half-degree spatial grid covering all oceans. Estimates of biomass by TLs were derived for marine ecosystems in an unexploited state, as well as for all decades since the 1950s. Trends in the decline of marine biomass from the unexploited state were analyzed with a special emphasis on predator species as they are highly vulnerable to overexploitation. This study highlights 3 main trends in the global effects of fishing: (1) predators are more affected than organisms at lower TLs; (2) declines in ecosystem biomass are stronger along coastlines than in the High Seas; and (3) the extent of fishing and its impacts have expanded from north temperate to equatorial and southern waters in the last 50 yr. More specifically, this modelling work shows that many oceans historically exploited by humans have seen a drastic decline in their predator biomass, with approximately half of the coastal areas of the North Atlantic and North Pacific showing a decline in predator biomass of more than 90%. © Inter-Research 2011.

Item Details

Item Type:Refereed Article
Keywords:Ecosystem modelling; Energy flow; Fisheries; Marine predators; Trophic level; biomass; catch composition; coast; coastal zone; ecosystem modeling; energy flow; energy flux; estimation method; marine ecosystem; numerical model; predator
Research Division:Agricultural and Veterinary Sciences
Research Group:Fisheries Sciences
Research Field:Aquatic Ecosystem Studies and Stock Assessment
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - Wild Caught
Objective Field:Wild Caught Fin Fish (excl. Tuna)
Author:Watson, RA (Professor Reginald Watson)
ID Code:83627
Year Published:2011
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2013-03-20
Last Modified:2013-03-20
Downloads:0

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