New discoveries and an innovative twist on monitoring methods – finding the unfindable.
Hydro Tasmania has been on a journey of rediscovery with respect to several freshwater threatened species.
Beddomeia tumida, a tiny species of freshwater snail considered likely extinct and not recorded since 1901 was rediscovered during a survey at yingina/Great Lake in January this year. An innovative technique involving salvaged roofing tiles deployed on the lake bed proved to be an effective, passive method of searching for mobile mollusc species. B.tumida was rediscovered during monitoring for another previously thought to be extinct snail species - the Great Lake giant freshwater limpet (Anyclastrum cumingianus). B.tumida is listed as 'endangered' under the Tasmanian Threatened Species Protection Act 1995, and 'critically endangered but possibly extinct' on the International Union for Conservation of Nature's (IUCN) red list.
The short-tailed rain crayfish (Ombrastacoides parvicaudatus) was first documented during surveys of the King River Valley in the ‘70s and ‘80s. It became formally recognised in 2006 and was listed as threatened on the IUCN red list. However Lake Burbury was built and areas of known habitat inundated. The species had not been recorded since and presumed to be extinct. Surveys were undertaken in 2020 / 2021 and together with several other species of freshwater crayfish, O.parvicaudatus was rediscovered at several sites in western inflowing tributaries of Lake Burbury. The species, whilst restricted in range (30-50 km2), persists in what appears to be a self-sustaining population.
eDNA applications were used to verify the new records of O.parvicaudatus and Hydro Tasmania is progressing eDNA marker development for a number of threatened galaxiid species. Several candidate gene regions for assays have been selected with field samples currently being analysed. eDNA is also used in our pest fish monitoring program.