Age, growth and non-flood recruitment of two potamodromous fishes in a large semi-arid/temperate river system
Article first published online: 11 MAR 2003
Copyright © 2003 John Wiley & Sons, Ltd.
River Research and Applications
Volume 19, Issue 7, pages 697–719, December 2003
How to Cite
Mallen-Cooper, M. and Stuart, I. G. (2003), Age, growth and non-flood recruitment of two potamodromous fishes in a large semi-arid/temperate river system. River Res. Applic., 19: 697–719. doi: 10.1002/rra.714
- Issue published online: 4 DEC 2003
- Article first published online: 11 MAR 2003
- Manuscript Accepted: 23 APR 2002
- Manuscript Revised: 3 APR 2002
- Manuscript Received: 31 MAR 2001
- Murray-Darling Basin Commission, Project N002.
- NSW Fisheries.
- Murray River;
- silver perch;
- golden perch;
Golden perch Macquaria ambigua (Percichthyidae) and silver perch Bidyanus bidyanus (Terapontidae) are two potamodromous fish species of the Murray-Darling river system in southeastern Australia. Ageing of these species using thin sections of the sagittal otoliths and validation with known-age fish revealed: they live for over 26 years; male and female silver perch reach maturity at 3 and 5 years respectively; male and female golden perch reach maturity at 2 and 4 years respectively; both species exhibit sexual dimorphism with larger females; and growth varies (L∞ silver perch 331–397 mm, golden perch 354–502 mm) among interconnected river systems. Longevity and opportunistic growth are characteristics that are well suited to the semi-arid and temperate hydrology of this river system. A flood-recruitment model for these two species, consistent with the ‘flood-pulse concept’, has previously been assumed to be the main mechanism of recruitment. The model appeared appropriate for this large, low-gradient river system with productive floodplains. However, in the middle reaches of the Murray River we found that golden perch recruitment was strong in non-flood years and poor in flood years, and silver perch recruited in all years. These data do not preclude golden perch recruiting during floods as well, because downstream larval drift may have resulted in strong year-classes being swept downstream of the sampling area during high flows. However, the recruitment models for these species need to be re-evaluated to include within-channel flows. Importantly, these flows can be manipulated by river regulation, unlike large floods, and therefore there is potential to enhance recruitment. Copyright © 2003 John Wiley & Sons, Ltd.