Use of instream wood habitat by trout cod Maccullochella macquariensis (Cuvier) in the Murrumbidgee River
Trout cod is an endangered species in New South Wales and has undergone a severe contraction in its range since European settlement. The species is currently found in the middle reaches of three waterways: the Murray and Murrumbidgee rivers (in NSW) and Seven Creeks (in Victoria). Research and recovery plans for trout cod have centred on the remnant population in the mid-reaches of the Murray River. However, little is known of the ecology of the species in the other parts of its range, including stocked populations in the Murrumbidgee River. The development of recovery plans for trout cod in the Murrumbidgee is hampered by the lack of specific local information about habitat use.
This paper is an output from a cooperative project between NSW Fisheries and the Cooperative Research Centre for Freshwater Ecology. The project investigated a trout cod population at a site in the mid-section of the Murrumbidgee River to identify habitat preferences for different life-history stages and to develop management guidelines for State/Local government agencies in this part of the catchment.
The study found that the occurrence of trout cod was significantly dependent on the presence of instream woody habitat. Trout cod were more likely to be found in close proximity to simple woody habitats, away from the river-bank. Unlike some previous studies, the abundance of trout cod showed no relationship with water velocity. The results will assist with specific management actions to restore and protect populations of this endangered species. In particular, existing instream woody habitats should be protected and additional structures added to the river in places where trout cod might be expected to live.