Egg and larval development of the New Zealand hokiMacruronus novaezelandiae

Abstract

The hoki Macruronus novaezelandiae (Macruroninae: Merlucciidae) is one of the most common fish species in the New Zealaid region. Hoki are widely distributed in subtropical and subantarctic water from c. 34° S to 54° S, with a depth range of less than 10 m to over 900 m. The eggs are positively buoyant, 1.01–1.14 mm in diameter (mean 1.07 mm), spherical with a smooth chorion and homogeneous yolk containing a single oil droplet c. 0.33 mm in diameter. Embryonic development takes 80 hours at 12 °C and the newly hatched larva is c. 2.2 mm in length. In artificially reared larvae the mouth begins to form 96 hours after hatching. After 5 days the yolk sac is almost completely absorbed, the mouth developed and the intestinal tract opened. Hoki eggs develop more quickly than eggs of species of Merluccius at similar temperatures. The size range of hoki eggs overlaps with those of other species spawning in the same area and time. Melanophore patterns are described which allow distinction of late‐stage eggs and the larvae.