In a new study funded in part by the Australian Government through the National Environmental Science Program’s (NESP) Resilient Landscapes Hub, researchers have discovered the endangered Australian brook lamprey (Mordacia praecox) living in streams as far north as Rockhampton, Queensland. This finding significantly extends the species’ known range by over 1,000 km and makes it the only lamprey species in the world to inhabit truly tropical waters.
From Larvae to Adults: The Life Cycle of the Australian Brook Lamprey
The Australian brook lamprey is a primitive jawless fish that grows up to 15 cm long and possesses rows of sharp teeth. Surprisingly, unlike most lamprey species, it does not use these teeth to suck blood, as it is non-parasitic. The species spends around three years as larvae, buried in stream bottoms and filter-feeding, before entering a non-feeding adult phase that lasts about one year.
Dr Luke Carpenter-Bundhoo from the Australian Rivers Institute at Griffith University and David Moffatt from DESI collaborated to confirm reports of Australian brook lamprey in Queensland, including on K’gari (Fraser Island). “It’s quite exciting to find an Endangered species so far out of its known range, yet so close to populated areas. We expect these animals naturally occur in Queensland, and have been here for an awfully long time, but have remained hidden due to their cryptic nature,” said Mr Moffatt.
Conservation Challenges: Mistaken Identity and Habitat Threats
The Australian brook lamprey faces numerous conservation challenges, including sedimentation, wildfires, and human developments. However, perhaps the most significant threat to its conservation is the difficulty in identifying the species. For most of its life, the non-parasitic Australian brook lamprey is indistinguishable from its more common blood-sucking southern relative, the short-headed lamprey (Mordacia mordax), which has a conservation status of ‘Least Concern’.
In their Endangered Species Research article, Dr Carpenter-Bundhoo and Mr Moffatt outline the difficulties of implementing a conservation strategy for this fish and propose some solutions. The species’ conservation is particularly crucial, as projected sea-level rises threaten to turn many of the lowland freshwater coastal streams where Australian brook lamprey live into saltwater habitats.
These new findings will better equip scientists to conserve this unusual and endangered species, which is especially important given the threats it faces from habitat loss and climate change.
