Pacific Bigeye Tuna Research Coordination Workshop
Bigeye tuna is the mainstay of longline fisheries throughout the Pacific basin. It is the principle target species of the Japanese distant-water longline fleet and a critical component of smaller-scale longline fisheries in Hawaii, French Polynesia and Australia. The landed value of the Pacific bigeye catch has been conservatively estimated to be approximately US$1.5 billion. The total landings of bigeye have been relatively constant for the last ten years at around 75,000 metric tons per year. Most of these landings are by longline vessels, but the proportion harvested by purse seine has been steadily increasing. Purse seine landings are composed of largely immature fish, and there are preliminary indications that these harvests may be having a detrimental impact on longline fisheries. Unfortunately, bigeye tuna is the least understood of the major tropical species, and in spite of its economic importance, less than 0.1% of the landed value is expended by the various research organizations around the Pacific on studies of this species. The lack of critical information on mortality rates and movement rates prevent scientists from making definitive evaluations of the status of the Pacific bigeye population.
In November 1998, the PFRP coordinated a workshop attended by tuna scientists from all major research institutions in the Pacific. The workshop participants discussed current and planned research on bigeye in their part of the world and identified research priorities and approaches for future work. The participants concluded that a well-designed, coordinated, large-scale, international tagging project is necessary to address the critical information gaps. The project they envisaged would utilize a variety of different tagging methods including simple dart tags, acoustic tracking devices, data logging archival tags and pop-up tags that transmit data to satellites. The choice of methods would depend on local circumstances, such as availability of bigeye for tagging, probability of recapture, and scientific hypothesis to be addressed. The workshop participants also concluded that a dedicated tagging vessel is necessary for long-term monitoring of tuna populations in the Pacific. This vessel would be a scientific asset to be utilized throughout the Pacific on a rotating basis to provide up-to-date information on changes in movement, mortality, and levels of exploitation. Participants were optimistic that the consensus they achieved will improve the prospects for increasing the general level of funding for research on this important but neglected natural resource.
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