Sand Flathead (Platycephalus bassensis) were one of the most commonly caught fish in the Bay. But since the 1950’s, their Bay population is believed to have declined more than 90%, cause unknown. SF’s were most abundant in the Bay on the muddy bottom of central basin, where they wait, partly buried in the soft seabed, to ambush prey including small fish, crustaceans, worms and molluscs.
Spot the fish....
Fish habitats in the Bay can be affected by physical changes to the seabed due to dredging and sedimentation; chemical changes such as introduction of industrial contaminants; and biological processes such as increased population and movements of other species.
Dumping of contaminated sediments dredged from the Yarra has been ongoing since a major river widening project in the 1940-s and 50’s. This dredge disposal site, around 20km south of Williamstown, is likely to have changed the physical and chemical nature of the central basin.
Even before the recent Channel Deepening Project, contaminants such as DDT, PCB, and others, were known to have dispersed from this site. But there seems to have been no thorough investigation of possible links between Sand Flathead decline and dredge spoil dumping. If such studies are underway, Baykeeper would love to hear about them!
