Koheru (Decapterus  koheru )                                                                       back     home

Koheru is a NZ species.

Koheru are found between North Cape and East Cape on the East coast of the North Island and they occur only in New Zealand waters.

Koheru are common in the clean waters of outer islands, whereas jackmackerels prefer the coastal waters.

Large schools of small individuals can be usually seen swimming above the bottom near cliffs and rocky reefs, whereas the larger fish form fast swimming schools further from the shore.

These fish usually eat small planktonic crustacean such as swimming shrimps, and larvae.

The koheru is an elongate fish, rounded in cross section.

The koheru can be distinguished from the jackmackerel by its firmer and rounder body, and a less pronounced lateral line without rough scales, which also curves more gradually than the sharp zigzag of the jackmackerel. It also has minute teeth that line it's flexible jaws, and the mouth can be protruded to form a plankton sucking tube.

They are 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 fin. They also have a number of small scutes along the lateral line just befor the tail.
Juveniles are usually green-yellow in colour.

Koheru can change colour rapidly, particularly their yellow stripe.

Koheru grow to about 20cm in the first year, and to about 32cm in the second year and after that the growth slows down to around 5cm a year. Maximum size would be 40cm or 16" in length.

Spawning is believed to be made in mid water during the summer months (Dec to Feb).

Koheru are eaten by many predators, and are sometimes used for bait.