Once in a while you come across something surprising. As you thumb through the fish guides, there’ll be the odd species that seems almost too beautiful to be found in Port Phillip Bay. Oyster Blenny is one of those species. Then when you look up their distribution on on iNaturalist, all you find are pictures of them in petri dishes or dead in divers’ hands. So, it was nice to come across glittering Oyster Blennies in Beaumaris shallows. And shallow they were. It was all I could do to find enough water to photograph them. It was a hard task too, as each time a boat passed offshore, the wake would bounce me up and down in the water.
Like so many of the discoveries that are to be made in the Bay, many of the fish that live around our coast, are found in knee-deep water or less. Like the Red Gurnard I found the other day at Ricketts Point (so shallow, I couldn’t get my camera under the water). The fact is, divers rarely venture shallow and snorkelers too often head deep, which kind of misses the point.
Finding Oyster Blennies
Oyster Blennies look more like a tropical fish. But they are found as far north as Cape York and all the way to South Australia. They are graceful with a long tapering tail, covered in small dots and fine wave-like marketings. The males have a crest like a Cassowary, gleaming facial stripes and beautiful blue spots on lace-like fins. The females and juveniles are darker and the young are almost black with a yellowish tail.
At Beaumaris, they occur in the shallows in front of the first beaches east of the Motor Yacht Squadron. Small family groups gather on the rocks covered in the white encrusting worm tubes, where there are healthy mussels. In fact, when I found the second group, they were feeding. There was a frenzy as a mussel was open and the Oyster Blennies and Tasmanian Blennies were ripping the white flesh from the shell.
The Oyster Blennies were quite nervous and quick to swim away if you make any sudden movements. Though I find, if I sat quietly, they were also quite curious. They would swim quite close to the camera among the mussels. The males weren’t particularly bold, so it took all of about two hours to get these photos.
As indicators of habitat quality
Oyster Blennies clearly aren’t common. Neither do they seem to like rocks covered in filamentous algae or sea lettuce. I suspect they are important indicators of water quality and like most blennies, may be very site faithful. Despite this, there is almost nothing known about them and they don’t seem to feature in the Great Victorian Fish Count results.
