Skipjack Tuna - Aku

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Deep Sea Fishing Skipjack Tuna – Aku

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Skipjack Tuna aka Aku (Katsuwonus pelamis)

Skipjack Tuna, also known as Aku, are fun and exciting fish to catch. They are prevalent in the waters surrounding all the Hawaiian Islands and run in large schools so, when you find a school of Aku, there’ll be plenty of opportunities to catch more than one!  The meat of Skipjack tuna is oily and dark. In Hawaii, larger Skipjack tuna are sometimes called otaru or otado. The larger aku, usually over 20 lbs., is sometimes good for sashimi or poke but all aku are great grilled or pan-fried. Aku are also used as live bait for Marlin.

Aku are small torpedo-shaped fish, averaging about 5 lbs., but with soft tissues around their jaw in conjunction with their speed and strength, they still take some effort to catch. Even so, they are great for beginners and younger anglers and provide an intermediate level of effort to catch.

Hawaii’s record for the largest Skipjack Tuna is 40 lbs. 8 oz. set by David Borgman on July 2, 2000 in Haleiwa.


Skipjack Tuna Fishing Season

January February March April May June July August September October November December
Oahu Fair Fair Good Good Good Good Good Good Good Good Good Good
Maui Good Good Good Good Peak Peak Peak Peak Peak Good Good Good
Kauai Good Good Good Good Peak Peak Peak Peak Peak Good Good Good
Big Island Fair Fair Fair Good Good Peak Peak Peak Good Fair Fair Fair

Best Time for Shortbilled Spearfish Fishing

Late winter early spring is the time in Hawaii for these fish.

They can handle cooler temperatures of water, they are available from late fall to spring.

Family: Istiophoridae (Billfishes)

Genus and Species: Tetrapturus angustirostris (shortbill), T. pfluegeri (longbill), T. belone (Mediterranean)

Range: The shortbill spearfish is known in the Pacific and Indian Oceans. It is caught year round off the Kona coast, one of the few areas where the spearfish is consistently caught. The longbill spearfish is known to occur in the northwest Atlantic from New Jersey to Venezuela, including the Gulf of Mexico. The Mediterranean spearfish is known to occur only in the Mediterranean Sea.

Description: Spearfish can be distinguished from other billfish by a slender, lightweight body, short bill, and a dorsal fin that is highest anteriorly (higher than in marlin and lower than in the sailfish). The vent is located well in front of the anal fin; in all other billfish, the vent is located close to the anal fin. The bill of the shortbill spearfish is barely longer than its lower jaw, whereas in the longbill spearfish it is about twice as long, but it is still noticeably short when compared to that in other billfish. The pectoral fins of the shortbill and Mediterranean spearfish barely reach to the curve of the lateral line; in the longbill spearfish, they extend beyond the curve. The longbill spearfish has more elements (45 to 53) in the first dorsal fin than any other Atlantic billfish, although it may appear similar to the white marlin. The shortbill spearfish has approximately the same count (47 to 50 elements), but the Mediterranean spearfish has fewer (39 to 46). The lateral line is single and arches above the pectoral fins. The dorsal fin is bright blue and has no spots. The vertical bars on the body are never as prominent as in other billfish and may show only slightly or not at all.


Natural History: These species are lesser-known and small members of the Istiophoridae family of billfish that are also referred to as slender spearfish. They are pelagic, offshore, deep-water fish that appear to be available all year in small numbers but are infrequently encountered by anglers in most parts of their range. They feed at or near the surface, mainly on small and medium-sized fishes and squids, including dolphin, sauries, flying fish, needlefish and pilot fish. They appear to be available all year in small numbers.

There is very little scientific information available on spearfish. It is widely believed that spearfish do not live much more than five years. They reach maturity after two years.

Fishing Information: Spearfish are not targeted gamefish anywhere in the world. Their numbers are too low (and catches too sparse) to be considered reliable game. They are caught with basically the same bait, lures, and tackle as white and striped marlin. However, most spearfish catches are considered incidental.

Other Common Names: Atlantic Spearfish, a’u, aguja picuda, furaikajiki.

Largest recorded: 74 pounds 12 ounces (shortbill); 94 pounds, 12 ounces (longbill); 90 pounds, 13 ounces (Mediterranean).


Sources: Marine Sportfish Identification, California Department of Fish and Game, 1987; FishBase, FishBase Consortium, 2001; Billfish, Saltaire Publishing, 1976

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