Studies on eggs and larvae of the garfish, <i>Tylosurus crocodilus</i> (Le Sueur)

Abstract

The eggs, early development of embryo, embryonic and early larval circulation and growth of <i>T. crocodilus</i> are described. The vitelline circulation is very prominent, showing intense ramification of ducts of Cuvier in the form of finer channels along the dorso-lateral side of the yolk region probably used for the absorption of the yolk material. The development of heart and circulation in the caudal region are described. An alternating pattern of fast and slow growth from day to day is found during embryonic development, with an average growth rate of 0.6 mm/day. The close agreement in the fin formulae of the larvae with that of <i>T. crocodilus</i> provides corroborative evidence that the eggs and larvae belonged to this species. The pigmentation is dominated by melanophores without specific arrangement over the body of the larvae. The larvae are highly carnivorous and aggressive. Observations during the first eleven days after hatching indicate that the larvae grow at a rate of 1.15 mm/day.