Movement patterns and flow requirements of five freshwater fish species from the Clarence River, Australia.
Butler G, Mackay B, Broderick T, Reinfelds I and Rowland S (2010) Movement patterns and flow requirements of five freshwater fish species from the Clarence River, Australia. Oral presentation given at the 13th International River Symposium, 11–4 October 2010, Perth, Western Australia.
Understanding river discharge requirements of fishes is essential when establishing environmental flow regimes for freshwater river systems. Two hundred individuals from three catadromous (Australian bass, Macquaria novemaculeata; freshwater mullet, Myxus petardi; and sea mullet, Mugil cephalus) and two potadromous (eel-tailed catfish, Tandanus tandanus; eastern freshwater cod, Maccullochella ikei) fish species were implanted with acoustic tags and monitored using an acoustic telemetry array, in the largely unregulated coastal Clarence River catchment, Australia. The array extended over 600 km of river from the lower estuary into numerous upper freshwater tributaries. Distinct seasonal migrations were undertaken by catadromous fishes, with a number of individuals travelling up to 300 km downstream to the estuary, before undertaking return upstream migrations some months later. Large-scale upstream and downstream movements were also recorded within potadromous species. Generally, the larger-scale migrations and movements of all five species were triggered by increases in river discharge, but not in all cases. Movements upstream and downstream were often impeded by instream barriers, with fish using increases in discharge to move over or around waterfalls and a man-made weir. This study highlights the importance of river discharge in the life-history of freshwater fishes, and provides information to improve management of Australia’s eastern coastal river systems.