Euthynnus affinis, the mackerel tuna, little tuna, eastern little tuna, wavyback skipjack tuna, kawakawa,
Euthynnus affinis formerly was known as Euthynnus yaito.[[1] World Register of Marine Species Euthynnus yaito Kishinouye, 1915]
Description
E. Affinis displays a typical tuna body shape with a slender, elongated body, and a deeply forked tail. It has a small amount of scales and 2 or more dark spots between the pelvic and pectoral fins. The first dorsal fin has 10-15 spines and is around 1/3rd of the tuna's body height. On its back, it displays 12 oblique stripes and a dark blue coloration for
countershading. It can reach a maximum length of and a weight up to .
To distinguish from the closely related black skipjack, also of the Pacific Ocean, the kawakawa has more broken stripes instead of straight stripes spanning the side of the body on the black skipjack. The stripes on the back of the kawakawa are more orderly than those of the
little tunny, which is primary found in the Atlantic Ocean.
Distribution and ecology
E. Affinis is an
Indo-Pacific species which is found from the
Red Sea to
French Polynesia,
but can also be found near Baja California.
The kawakawa is a Pelagic fish, highly migratory species, often schooling from the surface of the water to depths of . However, it often sticks close to coastal structures and Neritic zone instead of the open ocean. It is also known to commonly inhabit coastal reefs and move into estuaries.
It is a highly opportunistic feeder, eating squid, fish, , and zooplankton. Like other tuna species, it will often form large, multi-species schools with other like the yellowfin tuna and Frigate tuna.
Predators of E. Affinis include larger tuna, billfish, sharks, birds, and marine mammals.
Fisheries
While often being seen as an undesirable fish like others in its genus due to its strong taste and dark red meat, it is commonly eaten in
Hawaiian Islands and
Oceania cultures, as well as being used in
sashimi. The kawakawa is also caught in large amounts in the indo-pacific region, and is canned and sold frozen for human consumption. It is also commonly used for pet food.
Due to it being a reef-frequenting species, there is a possibility of ciguatera poisoning.
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