Early development ofForsterygion varium, Gilloblennius decemdigitatus, andG. tripennis(Pisces: Tripterygiidae)

Abstract

In the Wellington area (central New Zealand), F. varium (Forster, in Bloch et Schneider 1801) spawns from early June to late Nov., G. decemdigitatus (Clarke, 1879) from early June to early October and G. tripennis (Forster, in Bloch et Schneider 1801) from July-Oct. They deposit their eggs on firm substrates below the low tide level. Egg clusters are attended by an adult fish until hatching, which, in the laboratory at 11.5-13.5.degree. C, occurs after 18 days for F.varium and 20 days for G. decemdigitatus. Development to hatching for G. tripennis takes about 21 days at 13-15.degree. C. The egg development of all 3 spp. is illustrated. The yolk-sac larvae (prolarvae) of F. varium, G. decemdigitatus and G. tripennis at hatching average 5.85, 5.03 and 5.72 mm standard length, respectively. Yolk-sac larvae of F. varium have a single row of 9-17 small, stellate melanophores along the ventral midline of the tail The yolk-sac larvae of G. tripennis have up to 9 melanophores along the ventral midline of the tail, a medium-sized melanophore above the optic lobes and a further 2 above the medulla. The yolk-sac larvae of G. decemdigitatus have 3 large mid-dorsal melanophored interspersed with 5 smaller paler pigment cells and 3 large mid-ventral melanophores interspersed with 3 of the smaller cells.