Tagged tuna graphic by Nancy Hulbirt, SOEST Illustration.

PFRP Statistics & Modeling Projects

Biological, Economic, and Management Drivers of Fishery Performance: A Global Meta-analysis of Tuna and Billfish Stocks

Progress Reports: FY 2012, FY 2011

Project Summary

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:

  1. Describe the current status and recent trends in biomass and fishing mortality rates of tunas and billfishes around the world and produce summary papers in the scientific and popular literature.
  2. Evaluate the association between biological, economic, and management characteristics and differences in current stock status.
  3. Measure the impact of different management actions on fishing mortality rates for stocks experiencing overfishing (F> FMSY).


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:

  1. What are the current status and recent trends in biomass and fishing mortality rates of tunas and billfishes around the world?
  2. Which variables can explain differences in current stock status?
  3. Which management actions resulted in measurable changes in fishing mortality rates for stocks experiencing overfishing (F> FMSY)?

Expected Outcomes

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.

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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
Dr. Olaf Jensen, ojensen@u.washington.edu
Dr. Ray Hillborn, rayh@u.washington.edu
University of Washington
School of Aquatic & Fishery Sciences
P.O. Box 355020
Seattle, WA 98195-5020


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