Local conservationists fear a “miracle fish” may have been wiped out from its Sydney habitat due to botched construction work at a nearby public high school.
Climbing galaxies (Galaxias brevipinnis) belongs to a lineage of species that extends to Gondwanaland. It was only detected in 1998 in the Manly Dam area north of Sydney (the northernmost known location of the fish in Australia).
The fish breathes through its skin and uses its large pectoral and pelvic fins as suction cups to climb even waterfalls. Elsewhere, fish larvae need to reach the sea to begin feeding, but this population has somehow managed to survive by being confined to land by the dam.
But heavy rain last month caused sediment to overflow from the Forest high school practice field into Curl Curl Creek, the last Sydney waterway inhabited by climbing galaxies. More than two weeks later, the stream remains murky and conditions will likely limit the fish’s ability to catch mayflies and other insects.
“I’d hate to think that in 90 million years this will be the last on our watch,” said Malcolm Fisher, vice-chairman of the Save Manly Dam Catchment Committee (SMDCC).
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“We can’t say for sure whether he survived or not,” Fisher said. “But when you see the state of the water, you have to think that this is a huge blow.”
The Northern Beaches council also warned further silt flows were possible. He told SMDCC treasurer Ann Collins that a nearby sediment basin was “at capacity and cannot handle another major rain event,” according to correspondence seen on Jan. 25 — more than a week after the first event. By Guardian Australia.
The New South Wales Environmental Protection Agency said it sent staff to confirm that the stream and its source, Forest High School, had filled with mud on January 19 and 22. Initial investigations have identified workings at the school, but additional alluvial sources may also be found.
“We have advised the contractor and the NSW Department of Education to take immediate action to prevent water contamination,” a spokesman said. “Since silt consists of fine clay, the color of the water may remain for a while until it naturally washes away.”
The spokesman said the EPA was “not monitoring the rising galaxy population”, while the council was the appropriate body to carry out any monitoring. However, “at this stage, it appears that no aquatic life has been affected by the incident”.
The education department said its work was not responsible for the collapse, even though the EPA was the only party it wanted to take action.
“ADCO, the contractor responsible for the Forest high school construction site at Allambie Heights, carried out site inspections following a notification from the Environmental Protection Authority (EPA) regarding suspected silt flow at Manly Dam,” a department spokesman said.
Fisher said the education department had plundered nearby Manly Creek with its Manly Vale public school study a few years ago.
“There is absolutely no other source for all this siltation in Curl Curl creek other than the Forest High School cleared area,” he said.
But environmental advocates are skeptical that the EPA or other authorities such as the Northern Coast Council will actually measure any changes, including investigating whether the night fish are surviving.
“How do they know there is no impact on these streams?” said Ann Collins, SMDCC treasurer. “We should have some measurements of what it looks like on a regular basis or the content of all the different chemicals and materials.”
Curl Curl Creek has been rated as having the highest level of environmental significance, and its protection should be a priority for both local and state governments. “There are actually only three or four on the entire northern beaches,” Collins said.
“There is no management plan to really be sure [the fish] “It stays there,” he said. “You just feel like you’re hitting your head somewhere.” [a wall].”
The Australian Museum’s website says the fish has caused a stir before, including being the focus of a “major conflict between conservationists and developers” in 1999. This was just a year after it was discovered by scientist Andrew Lo.
His son Nathan Lo, a professor of evolutionary biology at the University of Sydney’s School of Life and Environmental Sciences, says there is good reason to be concerned about the fish’s fate.
“We know very little about the biology of fish, and silt flow does not normally occur in such environments,” Lo said. “[It] “It could stress not only climbing galaxies but also other aquatic environments.”
“Therefore, runoff events should be avoided as they may affect population survival,” he said.
It was possible for the species to reintroduce, but any new population would need to develop a capacity to survive when disconnected from the sea. Additionally, Lo said, “Reintroducing this would probably be a costly exercise, so it is better to stop such runoff events in the first place.”
The Manly Dam bushland is home to at least six threatened mammal species, including the eastern pygmy possum, according to a recent diversity survey. It is also home to the critically endangered Seaforth mint bush, among 1,120 plant species, and the endangered Duffys Forest ecological community.
Collins notes that a nearby facility wants 75 more parking spaces, which would result in the loss of trees, including those in the Duffys Forest ecological community. Such work would create another siltation threat.
24 luxury aged care homes are also planned nearby, as are new mountain bike trails sought by the local council and cyclists.
“What is already a very, very rare condition seems to be a barrier to all other developments that are emerging,” Fisher said.
Collins said it’s time for governments to draw a line so that climbing galaxies and other rare species can survive there.
“No, you have to think differently,” he said. “You can still do your jobs but you have to [them] another way.”