We’re always curious about what lays beneath the tannin stained waters of Bathurst Harbour. The creatures in this mysterious underworld have adapted to a darker, hidden place so often there is little known about them. The Maugean skate (Zearaja maugeana) is one such creature. It’s been described as a relic from Gondwana, coming from a time before fish had bones. So we asked Associate Professor Neville Barrett what makes this unique creature so intriguing:
1. Where and when was the Maugean skate discovered?
The Maugean skate was first discovered in Bathurst Harbour and Bathurst Channel in Port Davey by Graham Edgar during in the early 1980’s.
2. Where is it found now?
Only in the Bathurst Harbour/Channel estuarine system, and in similar waters in Macquarie Harbour. The largest population is found in Macquarie Harbour. Several recent attempts to find skates in Bathurst Harbour/Channel have not been successful, with the last sightings in the 1980s. This indicates that the population, if still present, is very small.
3. What makes it so unusual?
This skate is quite peculiar in a number of ways:
* It appears to be quite adapted to the estuarine environment and able to tolerate periods of low salinity (due to rainwater events) for some time, or at least avoid them by moving to deeper parts of the estuaries during floods.
* It is a close relative of deep-ocean species, rather than shallow coastal species.
* It is adapted to digging in the soft muddy seabed sediments for its food, again, the seabed environment is similar to the soft muds found in deeper offshore waters where its relatives appear to have come from.
* This species is very limited in its distribution being found in only two estuaries.
4. Is the Maugean skate under threat?
The skate is listed as endangered and is certainly under some significant pressure. The main population is found in Macquarie Harbour where there has been a well-documented decline in water-quality due to the expansion of salmonoid farming over the past decade.
5. Why do you find it so fascinating?
I’m fascinated by this species because it is a very late discovery in the fish fauna of Tasmania, and it’s amazing that such a large skate (62cm+) could be there, hidden under our noses for so long. There may yet be other surprises in store for us in such areas if we get the opportunity to look a little closer.
About Associate Professor Neville Barrett
I’m a research scientist and occasional lecturer in marine biology, based at the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania. My central research focus is on rocky reef fish biology and ecology, as well as the biodiversity and function of rocky reef ecosystems in general.