Clear as mud: the ecology and conservation of a secretive wetland fish (Neochanna cleaveri:Galaxiidae) in a heavily altered landscape

The rediscovery of presumed extirpated populations provides a second chance opportunity for species and habitat conservation. This study details the redetection of a westerly outlying population of a secretive wetland fish, the Australian Mudfish Neochanna cleaveri, as a positive note in the face of major environmental change. It also documents the basic ecology of the population to inform natural resource management and better understand the needs of similar habitat specialists. Nuclear genetic markers (allozymes) revealed the rediscovered population to be closely related to those in other parts of the range. Targeted sampling in the south east of South Australia indicated a robust population, occupying vegetated ephemeral wetlands and drains across two fragmented and contrasting systems. Movement sampling failed to detect migrating juveniles, which was supported by otolith trace elemental chemistry, that implied a wholly freshwater or at least non-marine lifecycle. Together these data indicate specific conservation management is warranted for a regionally disjunct and independent population and emphasises the importance of both remnant ephemeral wetlands and some artificial habitats for maintaining freshwater biodiversity across heavily altered landscapes.