1Commonwealth Scientific and Industrial Research Organisation, Land and Water, GPO Box 1666, Canberra, Australia Capital Territory 2601, Australia
2Commonwealth Scientific and Industrial Research Organisation, Land and Water, 120 Meiers Road, Indooroopilly, Queensland 4068, Australia
3Murray Darling Freshwater Research Centre, Co-operative Research Centre for Freshwater Ecology, P.O. Box 921, Albury, New South Wales 2640, Australia