Reproductive behaviour and early development of the honey blue-eye, Pseudomugil mellis Allen and Ivantsoff 1982 (Pisces : Pseudomugilidae), from the North-east Coast Divison, south-eastern Queensland, Australia

Abstract

Specimens of Pseudomugil mellis larger than 15 mm standard length (SL) showed sexual dichromatism as well as dimorphism in fin and body shape. Pairing occurred diurnally, with multiple releases of eggs amongst submerged vegetation between late morning and early afternoon when increasing water temperature reached 28� C. Eggs were demersal, adhesive and spherical (1.29-1.64 mm diameter) and had adhesive fibres (0.5-2.0 mm long) distributed (0.2-0.3 mm apart) over the chorion. Oil droplets (0.01-0.35 mm diameter) persisted throughout egg and larval development. Eggs hatched 112-190 h after spawning when they were incubated at 25-27�C. Yolk-sac larvae were 3.60-5.00 mm SL at hatching and began feeding at the surface after absorption of the yolk and oil droplets (3-80 h after hatching). All fin rays were developed in 9.0 mm SL fry, which feed at any depth. Aquarium-reared fish first spawned at 20 mm SL, when they were 95 days old. Features of Pseudomugil reproduction as they relate to a specific survival strategy and to taxonomy are discussed briefly.