Distribution and habitat associations of the endangered Oxleyan pygmy perch, Nannoperca oxleyana Whitley, in eastern Australia.
The Oxleyan pygmy perch Nannoperca oxleyana is a small, freshwater fish native to eastern Australia. The species is listed as endangered and a recovery plan has been prepared by the NSW Department of Primary Industries to guide conservation and management programs. However, incomplete knowledge of the species’ distribution, habitat requirements and the main threatening processes has constrained the effectiveness of recovery actions. This study therefore documents the distribution and habitat associations of the Oxleyan pygmy perch, Nannoperca oxleyana, in eastern Australia.
The Oxleyan pygmy perch was found to inhabit approximately 530 kilometres of coastline from Coongul Creek on Fraser Island, Queensland south to Tick Gate Swamp near the township of Wooli, New South Wales (NSW). Within this range, the species appears to have a disjunct distribution comprised of two main distribution centres: a narrow, 100 kilometre mainland stretch of coast between the Mary River Catchment and the Glasshouse Mountains region of southern Queensland and three contiguous offshore sand islands, and a narrow, 100 kilometre mainland stretch of coast between the township of Broadwater and the Wooli area in northern NSW.
The Oxleyan pygmy perch is confined primarily to freshwater habitats draining through sandy coastal, heathlands. It appeared to avoid fast flowing waters, being found only in slow flowing pools and backwaters of river channels and tributaries as well as in swampy drainages, lakes, ponds and dams. An abundance of structural aquatic habitat was a defining habitat feature either in the form of beds of aquatic 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 for fish.
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 Oxleyan pygmy perch.