The biology of a landlocked form of the normally catadromous salmoniform fish Galaxias maculatus (Jenyns). III. Structure of the gonads

Abstract

Changes in the gross morphology and histological structure of the gonads of a landlocked form of Galaxias maculatus inhabiting Lake Modewarre, south-western Victoria, are described in relation to the seasonal pattern of gonadal maturation outlined in a previous paper on the life history of this fish. Macroscopic changes in the gross morphology of the gonads are classified as to seven arbitrary maturity stages, these approximately corresponding, in the case of the male, with seven histological stages of testicular development. Nine stages of oocyte development in the ovaries of female fish are also outlined, and a single case of synchronous abnormal hermaphroditism is described. The above findings are then discussed in relation to those of previous studies on the gonads of a variety of teleost fishes, and in particular a number of other forms also belonging to the order Salmoniformes.