Comparative movements of four large fish species in a lowland river.

A multi-year radio-telemetry data set was used to comparatively examine the concurrent movements of the adults of three large-bodied Australian native freshwater fishes (Murray cod Maccullochella peelii, trout cod Maccullochella macquariensis and golden perch Macquaria ambigua) and the introduced carp Cyprinus carpio. The study was conducted over a reach scale in the regulated Murray River in south-eastern Australia. Differences were identified in the movements among these species. The predominant behaviour was the use of small movements (<1 km) for all species, and although larger-scale movements (>1 km) did occur, the frequency varied considerably among species. Large-scale movements were least evident for M. macquariensis and more common for M. ambigua and C. carpio with these two species also having a greater propensity to change locations. Macquaria ambigua displayed the largest movements and more M. ambigua moved on a 'continual' basis. Although a degree of site fidelity was evident for all species, the highest levels were exhibited by M. macquariensis and M. peelii. Homing was also evident to some degree in all species, but was greatest for M. peelii.