Yahoo News Sydney’s 90m-year-old climbing galaxias fish may have been wiped out by school building works
A “miracle fish” may have been snuffed out in its Sydney habitat by bungled construction work at a nearby government high school, local environmentalists fear.
The climbing galaxias (Galaxias brevipinnis) belongs to a species line reaching back to Gondwanaland. It was only identified in the Manly Dam region in Sydney’s north – the fish’s most northerly known location in Australia – in 1998.
The fish breathes through its skin and uses large pectoral and pelvic fins as suction cups to scale even waterfalls. Elsewhere, fish’s larvae rely on reaching the sea to start feeding but this population had somehow survived becoming landlocked by the dam.
Heavy rain last month, however, triggered an overflow of sediment from the Forest high school works site into Curl Curl Creek, the last Sydney waterway populated by the climbing galaxias. More then two weeks on, the creek remains turbid, conditions that will probably limit the fish’s ability to catch mayflies and other insects.
“I’d hate to think that on our watch, after 90 million years, that this is going to be the final end to it,” said Malcolm Fisher, deputy chair of the Save Manly Dam Catchment Commitee (SMDCC).
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“We can’t say for sure if it’s survived or not,” Fisher said. “But it’s a hell of a blow, you’d have to think, seeing the state of that water.”
Northern Beaches council has also warned more silt run-off was possible. It told the SMDCC treasurer, Ann Collins, on 25 January – more than a week after the first event – a nearby sediment basin “appeared to be at capacity and would not be able to cope with another large rain event”, according to correspondence seen by Guardian Australia.
The New South Wales Environment Protection Authority said it had sent staff on 19 and 22 January who confirmed siltation of the creek and its source, the Forest high school. Initial investigations singled out the school works, although additional sources of silt may be found.
“We advised the contractor and the NSW Department of Education to take immediate action to prevent water pollution,” a spokesperson said. “The colouration of the water may be around for some time until it naturally flushes, as the silt is from fine clay.”
The EPA “has not been monitoring the climbing galaxias population”, the spokesperson said, with the council the appropriate body to conduct any monitoring. However, “at this stage, it appears no aquatic life has been impacted by the incident”.
For its part, the education department said its works weren’t to blame for the siltation even though it was the only party asked by the EPA to take action.
“The contractor ADCO, responsible for The Forest high school construction site at Allambie Heights, carried out site inspections following a notification from the Environmental Protection Authority (EPA) about suspected silt run-off at Manly Dam,” a department spokesperson said.
Fisher said the education department had despoiled the nearby Manly Creek several years ago with its Manly Vale public school work.
“There is absolutely no other source for all that siltation in Curl Curl creek to come from other than the Forest high school’s cleared site,” he said.
Environment advocates, though, doubt 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 there’s no impact to those creeks?” the SMDCC’s treasurer, Ann Collins, said. “We should have some measures of what it looks like – or what the content of all the different chemicals and stuff are – on a regular basis.”
The Curl Curl Creek was graded as the highest level of environmental importance, and its protection should be a priority for both local and state governments. “There’s actually only three or four in the whole of the northern beaches,” Collins said.
“There’s no management plan to actually make sure [the fish] stays there,” she said. “You just feel like you’re beating your head against [a wall].”
The fish has caused a stir previously, including being the focus of “a major conflict between conservationists and developers” in 1999, the Australian Museum says on its website. That was just a year after its discovery by the scientist Andrew Lo.
His son, Nathan Lo, a professor of evolutionary biology at Sydney University’s school of life and environmental sciences, says there’s good cause to be worried about the fate of the fish.
“We know very little about the biology of the fish, and that silt runoff would not normally occur in these kinds of environments,” Lo said. “[It] could stress not only the climbing galaxias but other aquatic environments.”
“For that reason, runoff events should be avoided since they might impact the survival of the population,” he said.
Reintroducing the species was possible but any new population would have to develop a capacity to survive being cut off from the sea. In addition, “it would probably be a costly exercise to reintroduce, so it’s better to stop runoff events like that in the first place”, Lo said.
The Manly Dam bushland region is home to at least six threatened mammal species, including the eastern pygmy possum, a recent diversity survey found. It also hosts the critically endangered Seaforth mintbush among 1,120 plant species, and the endangered Duffys Forest ecological community.
Collins notes a nearby facility wants 75 more car parking spaces, which will result in tree loss including some in the Duffys Forest ecological community. Such work would create another siltation threat.
So too 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, very rare seems to be in the way of every other development that comes along,” Fisher said.
Collins said it was time governments drew a line if the climbing galaxias and other rare species are to survive there.
“Like, no, you have to think differently,” she said. “You can still do your things but you have to do [them] in a different way.”
