Pacific Skipjack Tuna

About The Species

U.S. wild-caught Pacific skipjack tuna is a smart seafood choice because it is sustainably managed and responsibly harvested under U.S. regulations.

Status

• According to the 2014 stock assessment, the Western and Central Pacific stock of skipjack tuna is not overfished and is not subject to overfishing.
• According to the 2015 stock assessment (SAR16), IATTC scientists are fairly certain that the eastern Pacific Ocean stock of skipjack tuna is not overfished and is not subject to overfishing, but this is not based on a full stock assessment.
• Skipjack tuna is a notoriously difficult species to assess. Due to skipjack’s high and variable productivity, it’s difficult to determine the effect of fishing on the population using standard fisheries data and stock assessment methods. Assessments are particularly difficult for the Eastern Tropical Pacific stock due to limited data.

Appearance

• Skipjack tuna do not have scales except on the corselet and the lateral line. The corselet is a band of large, thick scales forming a circle around the body behind the head and extending backward along the lateral line. The lateral line is a faint line running lengthwise down each side of the fish.
• Their back is dark purplish-blue, and their lower sides and belly are silvery with four to six conspicuous dark bands that run from behind the head to the tail, which may look like a series of dark blotches.

Biology

• Like other tropical tunas, skipjack tuna grow fast, up to nearly 4 feet and more than 70 pounds.
• They have a short life span compared to other temperate tunas, around 8 to 12 years.
• In the Pacific, skipjack are able to reproduce when they reach about 1.3 feet in length.
• They spawn throughout the year in tropical waters and seasonally (spring to early fall) in subtropical waters.
• Depending on their size, females produce between 100,000 and 2 million eggs each time they spawn.
• Once fertilized, the eggs hatch in about 1 day, depending on temperature.
• Skipjack spawn more than once a season, and some spawn almost every day.
• They are opportunistic feeders, preying on a variety of fish, crustaceans, cephalopods, mollusks, and sometimes other skipjack tunas.
• Large pelagic fishes such as billfish, sharks, and other large tunas prey on skipjack tuna.

Where They Live

• Skipjack tuna are found in tropical and subtropical oceans around the world, including the waters around the U.S. Pacific Islands and the U.S. West Coast. 

Management

• NOAA Fisheries and the Pacific Fishery Management Council manage this fishery on the West Coast.
• Managed under the Fishery Management Plan for U.S. West Coast Fisheries for Highly Migratory Species:
  • Fishermen must have a permit to harvest tuna and must keep logbooks documenting their catch.
  • Gear restrictions are in place to minimize bycatch.
  • Large purse seine vessels that fish for tuna in the eastern Pacific Ocean are required to have 100 percent observer coverage.
  • All other purse seine vessels must carry a fishery observer, if requested by NOAA Fisheries.
• NOAA Fisheries and Western Pacific Fishery Management Council manage this fishery in the Pacific Islands.
• Managed under the Fishery Ecosystem Plan for the Pelagic Fisheries of the Western Pacific:
  • Fishermen must have a permit to harvest tuna and must keep logbooks documenting their catch.
  • Gear restrictions and operational requirements minimize bycatch.
  • A limit on the number of permits for Hawaii and American Samoa longline fisheries controls participation in the fishery.
• Management of highly migratory species, like Pacific skipjack tuna, is complicated because the species migrate thousands of miles across international boundaries and are fished by many nations.
• Effective conservation and management of this resource requires international cooperation as well as strong domestic management.
• Two international organizations, Inter-American Tropical Tuna Commission (IATTC) and the Western and Central Pacific Fisheries Commission (WCPFC), manage this fishery internationally. Working with the U.S. Department of State, NOAA Fisheries domestically implements the IATTC and WCPFC conservation and management measures.
• The United States has implemented conservation and management measures adopted by the IATTC to control effort in the tuna purse seine fishery and reduce impacts to other species such as sea turtles, sharks, seabirds, and juvenile tunas.
  • Time/area closures to reduce the catch of juvenile tunas.
  • Required retention of tuna caught in the purse seine fishery.
• The United States has also implemented conservation and management measures adopted by the WCPFC to control juvenile tuna catch in the purse seine fishery targeting skipjack and to minimize impacts to non-target species such as sea turtles and sharks.
  • Limits on the number of days purse seiners can spend fishing in certain areas.
  • A seasonal prohibition on the use of fish aggregating devices by purse seine vessels.
  • Closure of specific high seas areas in the Western and Central Pacific to purse seine vessels.
  • A requirement for purse seine vessels to retain certain tuna species.
  • Purse seiners fishing in the WCPFC’s management area must also carry a fishery observer and must follow specific handling requirements in case they accidentally catch a sea turtle.
• 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.
• 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.
• In 2000, the United States established the Dolphin-Safe Tuna Tracking and Verification Program to monitor the domestic production and importation of all frozen and processed tuna products nationwide and to authenticate any associated dolphin-safe claim.