Koheru are found only between the North Cape and the East Cape of the North Island of New Zealand in mid-waters of reef and off-shore areas. They possess a more rounded, cylindrical body profile, similar to that of skipjack.
With similar colouring to a kingfish, koheru have a sharp, bright blue colour on the back, sometimes tinged with green, and silver white colour on the underside, with a prominent yellow stripe running along the back and on to the caudal peduncle. Juveniles are usually green-yellow in colour. Koheru can change colour rapidly, particularly their yellow stripe which they can suppress at will. They have minute teeth that line its flexible jaws, and the mouth can be protruded to form a plankton sucking tube.
HABITAT & FEEDING
Koheru swim in large schools usually feeding on planktonic crustaceans such as shrimp and larvae.
They can usually found around rocky reefs and pinnacles in cleaner offshore areas, and are best hunted in areas where the current is being pushed up against an obstruction – similar to kingfish territory.
AGE & GROWTH
Koheru can grow to between 25 and 50 cm, but are most common around the 20-30cm range. Their initial growth is rapid: first year=20cm, second 2year=32cm, and then approximately 5cm a year thereafter. Their usual maximum lifespan is 10 years. Spawning is believed to be made in mid- water during the summer months (Dec to Feb). Koheru are eaten by many predators and the larger groups will attract large pelagic fish so be alert When spearing these fish.
Many think that koheru is only good as a bait fish, but they are very good eating – cooked but especially raw.