Pacific Ocean tropical tunas include yellowfin, Thunnus albacares, skipjack, Katsuwonuspelamis, and bigeye, T. obesus, tuna. FRD scientists at the SWFSC in La Jolla contribute to research on Pacific tropical tunas by monitoring U.S. fisheries, monitoring and conducting stock assessments and participating in international forums for the assessment of the status of tropical tunas. These forums include the Inter-American Tropical Tuna Commission (IATTC), the Standing Committee on Tunas and Billfish (SCTB) of the Secretariat of the Pacific Community (SPC), the Interim Scientific Committee (ISC), and the Multi-lateral High Level Conference (MHLC).
The U.S. catches Pacific Ocean tropical tunas in recreational fisheries, and commercial gill net, purse seine, baitboat, troll, handline and longline fisheries. The majority of the catch is from purse seine fishing. The Pacific Islands Fisheries Science Center is tasked with monitoring longline fisheries in Hawaii, California and American Samoa, and Hawaii baitboat, troll and handline fisheries. FRD scientists in La Jolla, California are tasked with monitoring California gillnet fisheries, California recreational fisheries, and U.S. distant-water purse seine fisheries and baitboat fisheries. All data collected from these fisheries are used to assess the health of Pacific Ocean tropical tuna stocks.
U.S. commercial purse-seine and baitboat fisheries for yellowfin and skipjack tuna operate in the eastern tropical Pacific, and also in the central-western Pacific. Data are collected by the IATTC for U.S. purse seiners and baitboats fishing in the eastern tropical Pacific, as part of the Commission requirements.
SWFSC, FRD scientists in cooperation with the SWR office collect data for U.S. purse seiners in the central-western Pacific, as a requirement of the South Pacific Tuna Treaty that started in 1988. Logbook data, detailing daily activities of the fleet, and landings data are collected from 100% of the fleet. Catch length for yellowfin, skipjack, and bigeye tuna, and species composition data are taken by SWR biological technicians in American Samoa, as vessels unload at the canneries. The most significant development in the fishery has been a switch to fishing on Fish Aggregation Devices or FADs (380 kb text only or 9MB of text & figures) since 1995 (FAD sets). This new development has peaked FRD scientists interests in FAD research. Treaty data are computerized by FRD scientists and submitted bi-monthly to the Forum Fisheries Agency (Treaty Managers) in the Solomon Islands. Treaty data are also summarized annually by FRD staff and presented at the annual Treaty review. The results of this paper and other research (Discussion of Parameters and Comparisons of Areas Fished) are also presented annually to the SCTB.
California drift gillnet fisheries operate within the California EEZ, target swordfish and sharks, and also catch some quantities of yellowfin and skipjack tunas. The gillnet fishery started in 1980 and logbook landings and length data are collected by the California Department of fish and game (CDFG ). SWFSC, FRD staff assisted CDFG by computerizing logbook data from 1980 to 1992 and 1997. Since then CDFG has been computerizing these data. SWFSC, FRD staff use the data for fishery monitoring and assessments of tropical tuna and swordfish stocks.
California recreational anglers, using rod and reel fishing gear, also catch yellowfin and skipjack tunas. These tropical tunas are usually caught in waters off of Mexico during the summer months by anglers fishing on chartered, long-range party boats out of San Diego, California (H&M Landing, Fisherman's Landing, Point Loma Sportfishing). Catch data are collected by CDFG and used by SWFSC FRD staff for fishery monitoring and stock assessments.