Global Fisheries Collapse Predicted
Pew Marine Conservation Fellows Co-Author Science Article on Impacts of biodiversity loss on ocean ecosystem services.
November 06, 2006
A recent Science publication warns that the world will run out of seafood by 2048 if steep declines in marine species continue at current rates, based on a four-year study of catch data and the effects of fisheries collapses. The co-authors of the paper, written by an international group of ecologists and economists, include Pew Marine Conservation Fellows Carl Folke, Stephen Palumbi, and Enric Sala.
The recent paper, published in the journal Science (Worm et al. 2006), predicts the global collapse (defined as fish catches dropping below 10 percent of historic catches) of all currently fished taxa by 2048. The prediction is based on a meta-analysis of published data in which the authors examined the effects of declining species diversity on marine ecosystem services. Results suggest that the loss of biodiversity in coastal ecosystems has led to the impairment of critical ecosystem services, such as the filtering services provided by suspension feeders and submerged vegetation that contribute to the maintenance of high water quality. The authors also used the United Nations Food and Agriculture Organization’s global catch database for the period from 1950 to 2003 to examine relationships between biodiversity and ecosystem services in 64 large marine ecosystems (greater than 150,000 square-km).
This analysis revealed that 29 percent of all fished species had collapsed by 2003 and ecosystems with the fewest species suffered the greatest rates of collapse. The authors note that large marine ecosystems with higher species diversity also recovered more quickly following periods of overexploitation, perhaps due to the improved abilities of fishers to switch among species, thus giving overexploited species the opportunity to recover. Finally, the authors examined relationships between biodiversity and ecosystem services in 44 marine reserves and four large-scale fisheries closures. On average, these regions had species richness 23 percent greater than non-protected areas. Tourism revenue, measured as the number of dive trips, also was increased in these areas, suggesting that not only do diverse marine fisheries serve as major global food sources, but they also provide opportunities for recreation.
The authors conclude that the loss of marine biodiversity is negatively impacting the marine ecosystem services on which we depend. Yet they believe the trend is reversible and, therefore, urge the restoration of biodiversity through careful management of fisheries, maintenance of pollution-free habitats, and creation of marine reserves.
Worm, B., E.B. Barbier, N. Beaumont, J.E. Duffy, C. Folke, B.S. Halpern, J.B.C. Jackson, H.K Lotze, F. Micheli, S.R. Palumbi, E. Sala, K.A. Selkoe, J.J. Stachowicz, and R. Watson. 2006. Impacts of biodiversity loss on ocean ecosystem services. Science 314: 787-790.
Link to Abstract in Science Magazine