Distribution and habitat associations of the endangered Oxleyan pygmy perch, Nannoperca oxleyana Whitley, in eastern Australia

1.Detailed knowledge of habitat requirements is particularly relevant to the conservation of rare and threatened fish species because habitat fragmentation and loss are usually the major threats to species with limited distributions and restricted habitat requirements, and habitat restoration is typically the first step in species' recovery plans. This paper documents the macro-, meso- and microhabitat habitat associations of a small threatened percichthyid, the Oxleyan pygmy perch, Nannoperca oxleyana, in south-eastern Queensland and north-eastern New South Wales (NSW), Australia.2.The species' range encompasses approximately 530 km of coastline from Coongul Creek on Fraser Island, Queensland (25° 16'S, 153° 09'E) south to Tick Gate Swamp near the township of Wooli, NSW (29° 54'S, 153° 15'E). It is confined primarily to dystrophic, acidic, freshwater systems draining through sandy coastal lowlands and Banksia - dominated heath ecosystems.3.Both lentic and lotic environments provide habitat for N. oxleyana but the species is found only in slow-flowing pools and backwaters of river channels and tributaries as well as in swampy drainages, lakes, ponds and dams.4.Trapping studies found that an abundance of structural aquatic habitat was a defining microhabitat feature either in the form of beds of emergent or submerged plants or the presence of steep/undercut banks fringed with the semi-submerged branches and fine rootlets of riparian vegetation. When present, leaf litter and snags also provided cover.5.Recent and historical survey data suggest that human activities have had a significant influence on contemporary species presence/absence patterns and may have been responsible for the prominent gaps within the Queensland-NSW distribution of N. oxleyana.6.The distinctive relationships of N. oxleyana with features of aquatic habitat at the macro-, meso- and microhabitat scale demonstrate principles applicable to any study focused on the conservation of an endangered fish species.