Distribution and characteristics of the platypus (Ornithorhynchus anatinus) in the Murrumbidgee catchment
Little is known of the current status of platypus (Ornithorhynchus anatinus) populations in the Murrumbidgee catchment and other west flowing rivers in the Murray Darling Basin. Platypus distribution in the Murrumbidgee catchment was determined from sightings, reports by government departments, the literature and a capture release study. The platypus was found to be widespread in the catchment, including all subcatchment and elevation categories, but most reports were from the middle and upper subcatchments. Sixty five captures of 55 individual platypuses were made during 61 trap nights to 31 study sites in the Murrumbidgee catchment during 2009 10. Only three juveniles (all females) were captured and recapture rates were low, with only nine platypuses captured more than once. Adult males had body weights of 980 2180 g and body lengths of 42 60 cm (n 32) Adult females weighed 795 1480 g and were 38 52 cm long (n 20) Tail fat index was significantly affected by season and platypus age, while in comparison, season, platypus length and weight had a significant effect on tail volume index. This study established a baseline that provides a starting point from which the impacts of environmental disturbances or diseases occurring over time can be measured and investigated.