Monster Seminar Jam - Trends in Status of Global Marine Fisheries
Dr. Trevor Branch, Assistant Professor, School of Aquatic and Fishery Sciences, University of Washington
What are the prospects for global marine fisheries? Predictions made from trends in catch data suggest that around 70% of all fisheries are overexploited, 30% collapsed to less than 10% of original levels, and that the trend in these numbers is worsening over time. Conversely, compilations of stock assessments find lower numbers of overexploited (30%) and collapsed (10%) fisheries, and a trend in exploitation rates suggesting that most fisheries should rebuild in the future. FAO status reports agree with the stock assessment results. We found a substantial bias in the catch-based method explains most of this difference. For example, status estimates from simulated random catches with no trend also inexplicably suggest a worsening trend in status over time. However, there is much confusion over definitions of what should constitute overfished, and over whether stock assessments taken mainly from developed countries can be used to infer status and trends of the entire world. The greatest data gaps are the absence of reliable survey estimates of abundance from most of the developing world, yet most resources are expended on more detailed assessments of stocks in developed countries. I propose developing a global fleet of survey vessels operated by an international organization like the FAO to fill this need.
Date and Time:
November 17, 2011,
10:30 am - 1:00 pm