FishWatch

Harvesting Pacific Yellowfin Tuna

There are two stocks of yellowfin tuna in the Pacific Ocean, one in the western and central Pacific and one in the eastern Pacific. An important part of tuna fisheries in the western and central Pacific, yellowfin tuna is harvested in small-scale artisanal fisheries in Pacific Island and southeast Asian waters as well as by large distant-water longliners and purse seiners operating in equatorial and tropical waters. U.S. commercial fishermen operating in this area mainly use purse seines to harvest yellowfin tuna.

In the eastern Pacific, yellowfin tuna are primarily harvested by purse seiners from the Central and South America. The U.S. purse seine fleet operating in the eastern Pacific is small. Small purse seiners fishing off California for sardine and anchovy sometimes target yellowfin tuna when warm water from the south brings the species within their range, but West Coast–based fishermen no longer harvest large numbers of tropical tunas because U.S. canning facilities have relocated overseas.

Hawaii- and American Samoa–based longliners and U.S. Pacific Islands troll fisheries also harvest yellowfin tuna.

Although none of these fishing gears typically impact habitat, purse seines and longlines sometimes incidentally catch other marine species. Many purse seine fishermen use fish aggregating devices (FADs) to target tunas. FADs are natural floating or man-made objects that are found or placed on or near the ocean surface and used to attract schooling fish underneath. However, FADs can also attract non-target and bycatch species including juvenile tunas, sharks, other fish, and occasionally protected species. Bycatch of juvenile yellowfin and bigeye tuna is the most significant issue in the purse seine fishery. In the eastern Pacific and western and central Pacific, purse seiners are prohibited from fishing in certain areas and with FADs at certain times of the year to regulate fishing effort and reduce bycatch of juvenile tunas. Fishermen are also required to retain all tuna caught in the purse seine fishery. This measure is partly intended to encourage fishermen to target larger, more profitable adult tunas, rather than juvenile tunas (they are prohibited from discarding juvenile tunas to make room in their fish holds).

Interactions with protected species such as sea turtles, marine mammals, and seabirds in these fisheries are rare and survival rates are estimated to be high. Management restricts the type of fishing gear that can be used and prohibits fishing in certain areas to minimize impacts on protected species. In addition, longline fishermen are trained in safe handling and release techniques for sea turtles, seabirds, and marine mammals and carry and use specific equipment for handling and releasing these animals. Scientists and managers continue to monitor bycatch in these fisheries through logbooks and fishery observer programs.

Management

Although NOAA Fisheries and the fishery management councils manage our domestic yellowfin tuna fisheries, highly migratory species such as yellowfin tuna require cooperative international management to ensure they are sustainable.

Who’s in charge? The United States is a member of the Inter-American Tropical Tuna Commission and the Western and Central Pacific Fisheries Commission, both of which are responsible for the international conservation and management of tuna and tuna-like species in the Pacific Ocean. NOAA Fisheries and the Pacific and Western Pacific Fishery Management Councils collaboratively manage our domestic yellowfin tuna fisheries. Domestic management is guided by our participation in the two Commissions. Terms of the South Pacific Tuna Treaty also apply to U.S. purse seine vessels operating throughout the western and central Pacific. Purse seiners in the eastern Pacific also operate under the International Dolphin Conservation Program, a multilateral agreement aimed at reducing and minimizing bycatch of dolphins and undersize tuna.

Current management:

Fishery Management Plan for U.S. West Coast Fisheries for Highly Migratory Species.

• Permitting, logbook, and monitoring requirements.
• Gear and time/area restrictions, including a longline exclusion zone within 200 miles of the U.S. West Coast.
• Mandatory annual protected species workshops for all West Coast–based longline vessel owners and operators.
• Longline vessels and large purse seine vessels on the U.S. West Coast required to have 100 percent observer coverage. All other purse seine vessels must carry a fishery observer, if requested by NOAA Fisheries.

Fishery Ecosystem Plan for Pelagic Fisheries of the Western Pacific

• Permitting, logbook, and monitoring requirements.
• Gear restrictions and operational requirements to minimize bycatch and potential gear conflicts among different fisheries.
• Limited entry programs for the Hawaii- and American Samoa–based longline fisheries, limiting the number and size of vessels that can participate in the fishery.
• Longline prohibited fishing areas around the Main Hawaiian Islands, Northwestern Hawaiian Islands, Guam, the Northern Mariana Islands, and American Samoa to protect endangered Hawaiian monk seals and reduce potential gear conflicts and localized stock depletion (when a large quantity of fish are removed from an area); these zones are enforced through NOAA Fisheries Vessel Monitoring System (longline boats must be equipped with a satellite transponder that provides real-time position updates and tracks vessel movements).
• Hawaii- and American Samoa–based longline vessels must carry onboard observers when requested by NOAA Fisheries, in part to record interactions with sea turtles, seabirds, and marine mammals.
• Mandatory annual protected species workshops for all longline vessel owners and operators.

The United States has implemented the Inter-American Tropical Tuna Commission’s conservation and management measures for yellowfin tuna, including:

• Purse seine closures in the eastern Pacific.
• Requirement for vessels to retain all tuna caught in the purse seine fishery. This requirement is in place to encourage fishermen to target larger, more profitable adult tunas, rather than juvenile tunas (they are prohibited from discarding juvenile tunas to make room in their fish holds). If adult tunas are targeted, the fishery is more sustainable because these mature fish have probably had a chance to reproduce.

The United States has also implemented conservation and management measures for yellowfin tuna recommended by the Western and Central Pacific Fisheries Commission:

• Limits on the number of days purse seiners can spend fishing.
• Limits on catch of yellowfin tuna in the longline fishery.
• Seasonal closure of the purse seine fishery that uses fish aggregating devices in the western and central Pacific.
• Requirement for vessels to retain tuna species (for the same reason as above).

Under the South Pacific Tuna Treaty, U.S. purse seine vessels operating throughout the western and central Pacific Ocean must be registered and are monitored through logbooks, cannery landing receipts, national surveillance activities, observers, and port sampling.

Annual Harvest

U.S. harvest of yellowfin tuna in the Pacific makes up only a small percentage of the yellowfin tuna harvested worldwide. In 2010, Hawaii fishermen landed 2.4 million pounds of yellowfin tuna. American Samoa fishermen landed nearly 970,000 pounds of yellowfin tuna.

Economy

U.S. purse seine catch of yellowfin tuna from the western and central Pacific is mainly sent to canneries in American Samoa or other countries. The yellowfin catch from Hawaii- and American Samoa–based longliners is mostly sold for the fresh fish and sashimi market in Hawaii and the U.S. mainland. The small amount of yellowfin caught off California is consumed by the domestic market or is exported – fresh tuna goes to Japan and the Philippines and frozen tuna goes to Indonesia for processing.

RECREATIONAL

Recreational anglers fish for yellowfin tuna with troll, rod and reel, and handline gear and sometimes by free-diving with spear guns. Off California, anglers must be licensed and can only possess 10 yellowfin tuna per day. Recreational charter boats must keep logbooks of their catch. There are no federal regulations for recreational fishing off Hawaii and U.S. Pacific Island territories; however, local rules may apply.