Fears for our Gippsland Lakes dolphins

Scientists fear many of our unique Burrunan dolphins may have died, following high fresh water inflows into their habitat.

Fears numerous Gippsland Lakes Burrunan dolphins may have perished have emerged, following extended periods of rain and high freshwater inflows into their habitat.

During fauna surveys conducted in the Gippsland Lakes in the past year, 29 resident Burrunan dolphins have not been able to be found.

Some dolphins have been observed in poor condition, with ulcerative lesions and discolouration of their skin.

Decreased salinity in the lake system is believed to be the cause of the skin condition, according to the Department of Land, Water and Planning.

DELWP wildlife emergencies principal officer, Rodney Vile, said the absence of the dolphins from the lake system was “concerning”.

“While we are fairly certain that the low salinity levels have impacted the health of the dolphins, we do not know what has become of them,” he said.

“While there is a possibility that some have moved out of the lakes system into a more favourable environment, it is likely that many have died.”

Mr Vile said as a result of recent flood recovery funding, DELWP would increase the number of surveys and data collection.

“This will allow us to continue to monitor the population and hopefully see the numbers increase,” he said.

People venturing out and about on the Gippsland Lakes are also being urged to help out, by providing photographic evidence of dolphins.

Photographic data helps to record resident dolphins, identified by their markings and the shape of their dorsal fins.

Burrunan dolphins are a unique Victorian species, found only in the Gippsland Lakes and Port Phillip Bay areas, and surveys of the population are conducted quarterly in the lakes system over several days, with observational and photographic data recorded.

The data helps DELWP and the Marine Mammal Foundation to monitor the population and its movements and behaviours.

Foundation founding director, Dr Kate Robb, said the Gippsland Lakes, as an estuarine system, was subjected to substantial changes — which in turn affected the animals which lived there.

“Over the past year, the Burrunan dolphin population has endured several challenging adjustments to the overall water quality in their habitat, which has resulted in a number of reported deaths late in 2020,” she said.

“With every fauna survey, along with dolphin population and health assessments, we also gather numerous water quality measures, including salinity, turbidity and temperature, at 22 sites and share this data openly with partnering organisations.

“This information continues to paint a more complete picture of how we can support the long-term survival of the species.”

Citizen scientists and mariners on the Gippsland Lakes can help strengthen the breadth of data collected by uploading images of sighted dolphins to marinemammal.org.au/trakmm

Boats must remain at least 200 metres from whales and dolphins when in the water.

The next fauna survey is due in coming weeks.