Department makes significant Red Tide discovery
Released 21 Jul 2008
A species of red tide forming dinoflagellate called Noctiluca has been identified for the first time in Western Australian waters by the Department of Water's Phytoplankton Ecology Unit (PEU).
For almost thirty years the Department's Phytoplankton Ecology Unit has analysed water samples, identifying microalgae and macroalgae from dams, wetlands, drains, streams, rivers and estuaries from all over Western Australia.
Last week it received a marine sample from the Esperance area following reports of a "pink slime."
The PEU identified it as Noctiluca, a normally tropical species. Photographs of the sample were sent to Professor Gustaaf Hallegraeff from the University of Tasmania, who confirmed the PEU's diagnosis of this unusual event.
He believes that the Noctiluca reached Esperance from the tropical north where it flourishes, perhaps via the Leeuwin Current.
Noctiluca red tides have increasingly been observed on the Australian eastern seaboard and in Tasmania, where the species has established an over-winter population.
This strongly buoyant, large dinoflagellate (0.2mm-2mm diameter) is a species with a voracious appetite for fish larvae, microalgae and zooplankton which it catches with its comparatively large tentacle.
It is not toxic to humans, but releases unionised ammonia that can irritate the gills of fish, or taint shellfish with the smell and taste of ammonia. It has been linked, anecdotally, to rashes in swimmers who have swum in Noctiluca scums.
At night Noctiluca can produce a spectacular bioluminescence phenomena described as 'bluish light.'
"This is the first known record of a bloom by this species in Western Australia," Vas Hosja of the Department of Water's Phytoplankton Ecology Unit said. "The PEU is regularly involved in algal bloom incident responses in Western Australia, which has enabled it to identify many potentially harmful and nuisance species, and it maintains strong collaborative links with experts within Australia and overseas," he said.
The Department of Water said observations such as this around waterways, especially any scum events, should be reported as they may be potentially harmful or even toxic.
Contact: Peter Collins
Phone: (08) 6364 6848 / 0434 603 441