Exploring Solutions for Pacific Tuna Management
SFG has joined forces with The Nature Conservancy to work on reducing the tradeoffs between overfishing certain valuable tuna stocks and under-fishing others in the purse seine and longline fisheries in the Western and Central Pacific Ocean (WCPO). SFG has created a bioeconomic model to evaluate a suite of alternative management policies for tuna in this region, and using our model, we are able to forecast the effects of each policy on biomass in the water, catch, and profit. The primary goal of this project is to ensure that the Parties of the Nauru Agreement, a collectoin of eight island nations in the WCPO that govern the region's waters, are able to make infomed management decisions about their tuna fisheries, which are among the most valuable commercial fisheries in the world.
Accounting for about 60% of global tuna harvest, there is a growing concern that some stocks in the WCPO are being overfished, especially bigeye tuna. In order to chart a sustainable path forward, these fisheries need to overcome several challenges, namely a dramatic increase in purse seine fishing capacity and drifting floating aggregation devices (FAD) use, significant bycatch issues in the longline fishery and gaps in management capacity, and direct targeting of juvenile tuna in the archipelagic waters of countries like Indonesia.
Tuna fisheries in the WCPO are complex. They include multiple target species, multiple gear types, and they span the exclusive economic zones of more than a dozen nations, as well as large high seas pockets. Over the past decade, the number of purse seine vessels operating in the region has increased by 20%, and the sophisticated technology of FADs, which enable fleets to assess what is underneath the ocean's surface from hundreds or even thousands of miles away, has opened up new fishing grounds and made these vessels more efficient at catching fish of all sizes and age classes. It is estimated that at least 30,000-45,000 drifting FADs are deployed annually in WCPO waters, meaning each vessel in the region has more than 100 FADs. To date, the Parties to the Nauru Agreement have not identified an effective solution for managing FAD effort and the juvenile bigeye catch associated with it. Temporal FAD closures have been implemented, but they have had limited success in reducing juvenile bigeye catch. Given the dramatic increase in FAD fishing and its associated ecological impacts, SFG is developing a bioeconomic model that will inform future decision-making regarding management strategies that can effectively control overfishing in the WCPO region.
Using our bioeconomic modeling framework, we are evaluating a variety of management scenarios, including taxes on FADs, and tradable catch and effort systems in which fishers must purchase vessel days or catch quotas to regulate bycatch. With our model, we can project and compare outcomes--such as profits, distributional effects among fleets, and stock status--across the five different policies we are exploring.
This project is a collaborative effort between SFG and The Nature Conservancy.