Shibi Ahi – Kawakawa – Aku and Yellowfin – Big Eye taste comparison

As someone new to catching and eating the various tuna available in Hawaii, I had many questions about fish identification and taste comparison, and asked our panel of experts who catch and eat a lot of these. Thank you Capt Darren, Capt Erik, Shea and Take’s Seafood.

Most of us less-exposed to the fish caught off local boats call any yellowfin tuna an “ahi”. It turns out that “ahi” refers to yellowfin and big eye tuna over 100lb. Fish under 100lb are called shibi. Big eye tuna are plumper, with larger eyes since they generally live in deeper, colder water, making them fattier and tastier than yellow fin. In fact, big eye is much preferred to yellow fin despite the flesh being not as firm as yellowfin ahi. Sashimi aficionados say big eye has a delicate sweet taste, and yellow fin can be slightly bitter.

Aku is skipjack tuna, the type of tuna most commonly canned. It has the most *flavor* of all the tunas, which some people love; others find the iron taste off putting. Otaru is the name for aku larger than say, 20lb, and some fish lovers say otaru makes the best tasting sashimi of all the tunas because of the high fat content. Otaru become less “irony” and more fatty as they get bigger. Aku can reach 40lbs here but most are 5 to 25lb.

Kawakawa is called bonita or mackerel tuna in other parts of the world. Similar in taste to aku, it too gets better tasting when it reaches 20lb or so. The state record is 33lb.

Aku and kawakawa don’t get a lot of respect from the non-local anglers and eaters because they are bloody tasting and soft if not handled properly and commonly used as bait on the mainland. Ideally they should be bled well after braining them, and iced on the boat and overnight before cleaning. That will result in firm filets that have a shelf life of 2 to 3 days. The larger fish are fattier because they need the fat stores to prepare to spawn. 20lb fish are 2/3 of their max weight. A 2/3 grown yellowfin tuna is close to 200lb!

Shibi Ahi have a much better rep than aku and kawakawa, but the guys who have eaten the 3 tunas say that small yellowfin are kind of bland and don’t begin to have more flavor until they pass the 50lb to 70lb mark. For guys not wanting that hint of iron though, shibi ahi is the best because of its mild taste. It’s definitely the brightest looking with its yellow stripe, fins, tail and blue/black contrast.

We kayakers don’t get a shot at big eye, and even aku are usually out of range. Kawakawa come in the closest and can be caught inside of 100ft. They also aren’t that wary of hooks, line and badly presented baits. Shibi ahi are in range of the kayaks, often caught from 120ft to 300ft, but are sharp eyed and rarely fall for a bait on wire leader.

Hope this clears up some confusion with the similar looking and often misrepresented Hawaii tunas. Please let me know if anything else should be added.