Aspects of the biology of the Australian Grayling Prototroctes maraena Günther (Pisces : Prototroctidae)

Abstract

The Australian grayling, P. maraena, is generally regarded as Australia's most endangered freshwater fish species. A sample of 312 specimens from the Shoalhaven River, N.S.W., provided data on various aspects of its biology. The sample showed a bimodal length frequency distribution of 1 + and 2+ fish aged by otoliths. Grayling appear to suffer severe mortality, possibly as a result of spawning at age 2. The spawning season in the Shoalhaven River was from early February to early March and available data suggest that grayling are anadromous. P. maraena is a microphagic omnivore, and stomachs sampled contained principally cladocerans, algae and small insects. The need for further research to elucidate the grayling's habitat requirements and to determine effective conservation measures is stressed.