For Nathan Lo, a Sydney University professor, the multiple sightings of the galaxias brevipinnis stir both personal and scientific responses. It was Nathan’s father, Andrew Lo, who first identified the fish with a pedigree dating back 60 million years in the Manly Dam more than two decades ago – a surprise since the dam cuts off their typical migration to the sea.
“We have this amazing little fish that can make its way upstream to breed the way salmon do in Canada, and in Manly Dam it has been able to adapt to being cut off from the ocean 100 years ago, despite being in the middle of a city of five million people,” Professor Lo says. “It is the ultimate Aussie battler, and it’s amazing to be able to see it in its natural habitat.”
To Malcolm Fisher, a local resident and member of the Save Manly Dam Catchment Committee, the battle to keep developers from chipping away at the edges of the state park and threatening the fish “goes on all the time”.
“Developers can keep going back [for planning approval] until they get the decision they want, communities can’t,” Mr Fisher says.
Among the threats are plans to relocate the Forest High School to the current Warringah Aquatic Centre site, itself built on a former dump, a project that could leach toxic waste into the catchment if the soil is disturbed. The Beaches Link tunnel project too may result in the clearing of a forested site owned by Sydney Water and adjacent to the dam.
But the most urgent threat, Mr Fisher says, comes from an $18 million plan to build 24 luxury aged care homes at Allambie Heights, just above the Curl Curl Creek.
The project would clear habitat for at least eight threatened species, including the eastern pygmy possum, the large-eared pied bat, powerful owl and red-crowned toadlet, as well as increasing downstream risks for the fish.
“In times of heavy rain, [the deluge of mud and silt] just can’t be stopped,” Mr Fisher says.
A spokeswoman for the Northern Beaches Council says the project, at 181 Allambie Road, is still being assessed by the council and will go to the Local Planning Panel for a final decision.
Sonya Ku, meanwhile, is leading a team of citizen scientists to conduct what will be the most comprehensive study of the Manly Dam’s wildlife riches. Ms Ku had feared the climbing galaxias might have become locally extinct as nobody had reported seeing them for 13 years before her recent findings.
“The scope of this study is unprecedented for the Reserve, perhaps then we will also have a few surprise discoveries,” she says.
Peter Hannam writes on environment issues for The Sydney Morning Herald and The Age.