Growth of Australian bass Maquaria novemaculeata (Perciformes : Percichthyidae) in the Sydney Basin

Abstract

Habitat type and sex are the principal determinants of the variable length-at-age of M. novemaculeata. Growth was studied in three main habitat types: lagoons, gorge streams, and freshwater estuarine habitats, and a total of 1071 adult bass and 644 young fish were examined. Observations were made on the growth of young wild bass, and their rapid growth after stocking in isolated lentic waters was measured.

The three von Bertalanffy growth parameters were estimated for populations from the main habitat types. A growth curve generated from tag-return data provided comparable values. Variation in length was tested by three-way ANOVA using age, habitat type and sex as independent variables. Female bass grew faster than males towards a larger asymptotic size (L∞ = 396 mm). Lagoon populations grew the most rapidly, and those in freshwater tidal sites grew slowest. T'he proportion of variarion in bass length that was due to habitat type, sex, and age was 15, 10, and 56% respectively. Marked flexibility of the growth, diet and reproduction of M. novemaculeata is seen as an adaptive response to variable environmental conditions.