Climbing galaxies (Galaxias brevipinnis) in Curl Curl creek, Manly Vale. Environmentalists fear the impact on species of polluted runoff from a school construction site.Photo: Greg Wallis
A “miracle fish” could have been snuffed out in its Sydney habitat by bungled construction work at a nearby government school, local environmentalists fear.
the climbing galaxies (Galaxias brevipinnis) belonging to a line of species extending back to Gondwanaland. It was only identified in the Manly Dam region of northern Sydney – the best-known location for the fish in Australia – in 1998.
The fish breathes through its skin and uses large pectoral and pelvic fins as suction cups to even scale waterfalls. Elsewhere, fish larvae rely on reaching the sea to begin feeding but this population had somehow survived being buried by the dam.
However, heavy rains last month prompted an overflow of sediment from the Forest high school works site into Curl Curl Creek, the last waterway in Sydney where the climbing galaxies were. More than two weeks later, the lake remains murky, conditions that will likely limit the fish’s ability to catch mayflies and other insects.
“I hate to think that on our watch, after 90 million years, this is the end of it,” said Malcolm Fisher, vice-chairman of the Save Manly Dam Catchment Committee (SMDCC).
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“We can’t say for sure if he’s safe or not,” Fisher said. “But it’s a devastating blow, you’d have to think about the state of that water.”
The Northern Beaches Council has also warned that more silt could be washed ashore. She told SMDCC treasurer Ann Collins on January 25 – more than a week after the first event – that a nearby sediment basin “appeared to be at capacity and would not be able to handle another major rainfall event ”, according to correspondence seen. by Guardian Australia.
The New South Wales Environmental Protection Authority said they sent team members on January 19 and 22 who confirmed the siltation of the lake and its source, Forest High School. The initial investigations pointed to the school works, although additional sources of silt could be found.
“We have advised the contractor and the NSW Department of Education to take immediate action to prevent water pollution,” a spokesman said. “The coloring of the water may be around for a while until it drains naturally, as the silt is from fine clay.”
The EPA “is not monitoring the population of climbing galaxies”, the spokesman said, with the Council as the appropriate body to carry out any monitoring. However, “at this stage, the incident does not appear to have had any impact on aquatic life”.
As for the education department, the education department said that their labor was not to blame for the siltation even though it was the only party that the EPA asked to take action.
“Contractor ADCO, responsible for The Forest high school construction site at Allambie Heights, carried out site inspections following notification from the Environmental Protection Authority (EPA) of a suspected silt runoff at Manly Dam,” a spokesman said. part of the Department.
Fisher said the education department had destroyed nearby Manly Creek several years ago with its Manly Vale public school work.
“There is no other source for all that silt in the Curl Curl stone to come from other than the cleared site of the Forest high school,” he said.
However, environmental advocates doubt that the EPA or other authorities such as the Northern Beaches council will actually measure any changes, including investigating whether the nocturnal fish have survived.
“How do they know those ponds are unaffected?” said SMDCC treasurer, Ann Collins. “We should have some measurements of what it looks like – or the content of the various chemicals and things – on a regular basis.”
The Curl Curl Creek has been graded as the highest level of environmental importance, and its protection should be a priority for both local and state governments. “There are only three or four of the northern beaches,” Collins said.
“There is no definitive management plan [the fish] she stays there,” she said. “You just feel like you’re hitting your head [a wall].”
The fish has caused turmoil before, including being the focus of a “major conflict between conservationists and developers” in 1999, the Australian Museum says on its website. That was only a year after scientist Andrew Lo discovered it.
His son, Nathan Lo, professor of evolutionary biology at the school of life and environmental sciences at the University of Sydney, says there is good reason to worry about the fate of the fish.
“We know very little about the biology of the fish, and silt runoff would not normally occur in these environments,” Lo said. “[It] it could emphasize not only the climbing galaxies but other aquatic environments.”
“For that reason, runoff events should be avoided as they may affect the survival of the population,” he said.
It is possible to reintroduce the species but any new population would have to develop an ability to survive when isolated from the sea. Furthermore, “it would probably be an expensive exercise to reintroduce it, so it would be better to stop such runoff events in the first place”, Lo said.
There are at least six threatened mammal species in the Manly Dam bush region, including the eastern pygmy possum, a recent diversity survey found. In addition, Seaport’s minibush is highly endangered among 1,120 plant species, and the endangered Duffys Forest ecological community.
Collins notes that a nearby facility wants an additional 75 parking spaces, which will result in the loss of trees including some of the Duffys Forest ecological community. Such work would create another siltation threat.
So would plans for 24 luxury aged care homes nearby, as would new mountain bike trails sought by the local council and riders.
“What was already very rare seems to be getting in the way with every other development that comes after it,” Fisher said.
Collins said it was time for governments to draw a line if the climbing galaxies and other rare species are to survive.
“Like, no, you have to think differently,” she said. “You can still do your things but you have to [them] in another way.”