Skipjack Tuna

Physical Description

Purse seine vessels target skipjack tuna.
© Hélène Petit / WWF-Canon

Skipjack have a streamlined body that is mostly without scales.  Their backs are dark purple-blue. Their lower sides and belly are silver with 4 to 6 dark bands.  Skipjack can live as long as 8-10 years, growing around 3 feet long and 40 pounds.

Habitat and Distribution

Skipjack are highly migratory and are found throughout the Pacific, Atlantic and Indian Oceans between 45 degrees North and 40 degrees South.  Skipjack usually swim near the surface at night and can dive up to 850 feet during the day.  Large schools of adult skipjack tuna often mix with juvenile yellowfin and bigeye tuna.  

Diet

Skipjack feed on smaller fish, crustaceans, mollusks, and squid.  Skipjack are also cannibalistic.

Reproduction

Skipjack mature early, around age 1 and at about 16 inches long.   Skipjack spawn throughout the year.

Threats

Skipjack tuna are abundant throughout their range and populations appear healthy. However, since juvenile yellowfin and bigeye tuna often school with adult skipjack, they are caught by purse seine vessels that target skipjack. This bycatch of juveniles contributes to overfishing of the populations.

Policy

Skipjack fisheries are managed by

• The International Commission for the Conservation of Atlantic Tuna (ICCAT) in the Atlantic Ocean
• The Indian Ocean Tuna Commission (IOTC) in the Indian Ocean
• The Western and Central Pacific Fisheries Commission (WCPFC) in the Western Pacific Ocean
• The Inter-American Tropical Tuna Commission (IATTC) in the Eastern Pacific Ocean