Reproductive strategy and growth of the crimson-spotted rainbowfish, Melanotaenia splendida fluviatilis (Castelnau) (Pisces : Melanotaeniidae) in south-eastern Queensland

Abstract

M. s. fluvlatilis has a well-defined annual reproductive cycle in south-eastern Queensland. Spawning is confined to October, November and December, with the peak in October, before the onset of summer floods and unpredictable water levels in coastal streams. Juvenile fish grow rapidly and reach maturity in the year following hatching. Growth in both sexes conforms to the von Bertalanfi model, but males grow faster and to larger sizes than females. Differences in the reproductive strategy of M. s. fluviatilis in southern Queensland and that of the more northern subspecies, M. s. splendida, may be related to the relative predictability of flooding, and hence to the probability of egg and juvenile survival, in the two areas. M. s. fluviatilis has low fecundity but the species is, nevertheless, abundant in suitable environments.