Spatio-temporal spawning patterns of two riverine populations of the threatened Macquarie perch (Macquaria australasica)

Abstract

Understanding species-reproduction dynamics is vital for the management of riverine fish. Information on the spawning ecology of the endangered Australian Macquarie perch (Macquaria australasica) is based largely on data gathered from lacustrine populations, with uncertainty on the applicability such data has for managing riverine populations. The current study presents a first description of spawning patterns of two riverine populations of Macquarie perch in Victoria, Australia, using egg counts recorded across multiple sites and periods within the species core spawning window. Spawning intensity was highly variable between study sites, with 96 and 82% of eggs collected from a single site in the King Parrot Creek and Yarra River respectively. We also found a strong positive association between spawning and water temperature. Our results provide an important account of spatio-temporal spawning patterns of riverine Macquarie perch populations and lend some support for the transfer of information from lacustrine populations (as demonstrated by spawning habitat and temperature association). Although the spatial and temporal constraints of the present study must be considered, the results provide opportunity for further testing of the environmental effects, and management options aimed at enhancing spawning of this endangered species.