Progress Reports: FY 2012, FY 2011
The status of tuna and billfish stocks differs widely among species and regions and is poorly understood outside the tuna management community. Among the tunas and billfishes there is substantial variability in life history characteristics, such as longevity and age at maturity, thought to play a role in vulnerability to overfishing. There is similar variability in the economic characteristics of their fisheries including the price and the costs of capture and historical subsidies Finally, there are substantial differences among the Regional Fishery Management Organizations (RFMOs) that manage tuna and billfish stocks between the methods used to provide scientific advice, and the relationship between scientific advice, management regulations, and actual catches.
Project researchers propose a global comparative analysis of tuna and billfish stock status with the following objectives:
Stocks considered in this analysis will include: 23 stocks (total) of albacore, bluefin, yellowfin, bigeye, and skipjack tunas; at least 3 swordfish stocks; and at least 4 stocks of istiophorid billfishes.
The objective is to address three primary questions:
The goal of this research is to improve management of large pelagics by focusing attention on biological, economic, and management factors associated with successful fisheries. The global status analysis (Q1) will paint a more accurate and nuanced picture than previous high-profile publications based on catch or catch per unit of effort data (e.g., Myers and Worm 2003, Worm et al. 2006) and will include a broader range of stocks than previous syntheses based on assessment data (Sibert et al. 2006). Analysis of correlates of fishery status (Q2) will improve our understanding of the factors driving depletion of large pelagics. Most previous work has focused on biology, but economics is likely to be at least as important. Inherent in Q2 and Q3 is an evaluation of the relative success of different RFMOs in preventing depletion and overfishing (Q2) and responding rapidly and sufficiently once overfishing is recognized (Q3). Analysis of time series data (Q3) will also provide a quantitative comparison of the effectiveness of different management actions ranging from mandatory reductions in total catch to voluntary measures to reduce bycatch.
Funding for this project to be available late 2010.
[ Top of the page ]
Myers, R.A., and Worm, B. 2003. Rapid worldwide depletion of predatory fish communities. Nature 423:280-283.
Sibert, J., Hampton, J., Kleiber, P., and Maunder, M. 2006. Biomass, size, and trophic status of top predators in the Pacific Ocean. Science 314: 1773-1776.
Worm, B., Barbier, E.B., Beaumont, N., Duffy, J.E., Folke, C., Halpern, B.S., Jackson, J.B.C., Lotze, H.K., Micheli, F., Palumbi, S.R., Sala, E., Selkoe, K.A., Stachowicz, J.J., and Watson, R. 2006. Impacts of biodiversity loss on ocean ecosystem services. Science 314: 787-790.
Principal Investigators |
|
Dr. Trevor Branch, tbranch@u.washington.edu |
Download free Adobe Acrobat Reader to view PDF files.
[ Top of the page ]