Early development and buccal incubation in the fork-tailed catfish Arius graeffei Kner & Steindachner (Pisces : Ariidae) from the Clarence River, New South Wales

Abstract

Fertilized oocytes of A. graeflei ranged from 12.3 to 15.2 mm in diameter (mean 13.3 mm). Eggs and larvae were incubated orally by the male; maximum observed brood size was 83. The branchial region of brooding males became distended to accommodate the eggs and larvae, and the oral epithelium thickened to cover the palatine tooth patches. The brooding period lasted from 6 to 8 weeks, with hatching at 4-5 weeks. Larvae began feeding on plankton soon after hatching, and juveniles were up to 59 mm total length when released. The average increase in weight from fertilization to release was 20%.