EGG SIZE AND LARVAL DEVELOPMENT IN CENTRAL AMAZONIAN FISH

The relationship between larval development and egg size was studied in 14 species of Central Amazonian fish (seven characiforms, five cichlids and two siluriforms). Egg size was measured as yolk dry weight at activation (egg minus chorion). Larval development was measured as larval dry weight and age (h from activation) at the developmental stages. Egg size explained most of the variability of larval body weight and total larval weight at hatching, pectoral bud formation, eye pigmentation, jaw formation, swimbladder inflation, onset of swimming, first feeding and maximum weight attained with exclusively endogenous feeding. Larval ages at these developmental stages were poorly related to egg size. Other variables, such as the weight-specific yolk caloric content of the eggs (cal mg(-1)), spawning site (river or lake) and phyletic relationships had no effect on the remaining variance. These results suggest that the developmental stages considered were conservative among the species examined and that a sequence of stages occurs in the larval development of Amazonian larval fish. The resistance of the larvae to starvation was not related to egg size.