Rearing experiments with five species of Australian freshwater fishes. I. Inducement to spawning

Abstract

Experimental work on the reproduction of five species of fish endemic to Australia indicates the importance of specific water temperatures and floods as triggering mechanisms for spawning and for subsequent survival of young. Evidence has been obtained which suggests that the factor which stimulates the fish to spawn is produced when water comes into contact with dry soil. The species studied were Tandanus tandanus, Plectroplites ambiguus, Maccullochella macquariensis, Bidyanus bidyanus, and Carassiops klunzingeri. The spawning of these species is compared with some observations made on the heterochthonous Perca fluviatilis. Plectroplites ambiguus and Bidyanus bidyanus spawn at water temperatures above 23°C provided there is an accompanying rise in water level; both species produce pelagic eggs. Tandanus tandanus spawns at a temperature of 24°C and demersal eggs are laid in a gravel nest; a rise in water level is not essential. Maccullochella macquariensis spawns at 20°C provided there is a slight "run off" of water into the pond; eggs are laid in hollow logs or in similar situations. Carassiops klunzingeri spawns at 22.5°C and the eggs adhere to grass and twigs at the water's edge. Perca fluviadilis spawns at 11.5°C and all fish spawn in ponds over a short period if additional water is added, this ensures a more uniform water temperature throughout the pond.