A prehistoric fish in Manly Dam
A little over a year ago, the Manly Observer featured a story on the hunt for a pre-historic fish in Manly Warringah War Memorial Park, the Climbing Galaxias. Jack Kelly reported on the issue of ADCO Constructions (working on the new Forest High School build in Allambie Heights) being fined by the NSW Environment Protection Authority (EPA) for allowing muddy siltation to pollute sensitive creeks in Manly Dam’s catchment. In his article Jack mentions, that Scientists Sonya Ku and Jodi Rowley observed the presence of the Climbing Galaxias, albeit not as prolific as before.
Over the course of last year, heavy rains continued to cause sediment runoff into Manly Dam’s creeks. Hence, after several follow-ups by Mal Fisher of the Save Manly Dam Catchment Committee & subsequently by Michael Regan’s Office, the EPA is now funding a study by Environmental Scientist and Consultant, Sonya Ku to check back on the populations of the Climbing Galaxias from that last survey in late 2024. As part of this initiative, Sonya, led a team of Citizen Scientists from our group, last week to head to Manly Dam and check in on how the prehistoric fish is faring.
On a warm summer evening a few weeks back, the citizen science team gathered to fill up on pizza and set out for Manly Warringah War Memorial Park to look for the Climbing Galaxias. The Climbing Galaxias is known to actually scale the rocky cascades of Manly Dam and is a relic of the Gondwanan super continent, thought to have existed here for 90 million years. Learn more about them here.
As the last light of the sun started to fade over the horizon, we set off on the trail leading to the creek which was the designated transact. We walked in the growing darkness, our eyes remained peeled for spiders and ears tuned to the sounds of frogs and the occasional call of the tawny frogmouth.
Before we even got to the creek, we encountered bats flying overhead, the eastern toadlet and more, reminding us once again what a special place Manly Dam is, full of little creatures.
Once at the creek even before we started looking for the Climbing Galaxias, we were greeted by the Spiny Crayfish (Euastacus australasiensis) and the Giant Water Spider (Megadolomedes trux) and found a single Climbing Galaxias swimming by itself.
So we continued our search downstream and came upon the Southern Leaf-tailed Gecko (Phyllurus platurus), the Eastern Water Dragon (Intellagama lesueurii), Triangle Hawk Moth (Coequosa australasiae) and the Eastern Water Skink (Eulamprus quoyii) and more across various sections of the trail.
The general level of water in the creek was quite low and at one stage we found a crayfish stranded in a very small pool of water. After a while, we finally came upon a section of the creek which was more favoured by the fish we were after, the Climbing Galaxias. We spotted a couple of adults with the familiar stripes and specialised pectoral fins and alongside them a number of juvenile ones too, one of them in the video featured here.
By the end of the evening, across various sections of the creek collectively we spotted three adult Climbing Galaxias and five juvenile. A hopeful sign that the fish are not only present in the creek but are doing better than the last time it was surveyed which was right after the sedimentation pollution events.
So far the fish have continued to outlive the challenges that development around Manly Dam has posed, but it remains up to us to not only protect the fish but everything else that calls Manly Dam home.
Images © Malcolm Fisher & Aditi Das Patnaik