Australia: Turtles and dugongs die in droves

9News 26 Sep 11;

Deaths of turtles and dugongs off Queensland have nearly doubled this year as seagrass struggles to recover from floods, an international conference on rivers has heard.

The Department of Environment and Resource's Dr Julia Playford told the International River Symposium in Brisbane that the animals were scavenging mango seeds and algae because seagrass beds, their major food source, had been destroyed by sediment, turbidity and low salinity after last summer's floods and Cyclone Yasi.

She said one million tonnes of sediment had washed into Brisbane's Moreton Bay from the floods, three times the annual average in just 10 days.

South of Brisbane, 344,000 tonnes of sediment flowed down the Logan and Albert rivers, 10 times the annual load.

In the state's north, Cyclone Yasi had stirred up sediment at depths of up to 190 metres.

"That has been followed up with a significant increase of strandings of marine wildlife," Dr Playford told the symposium.

In the year to September 20, 150 dugongs had become stranded, with only three released, she said.

That's compared to 68 in the same period in 2010, 37 in 2009 and 30 in 2008.

Meanwhile, 999 turtles had died, compared with 555 in 2010, 625 in 2009 and 552 in 2008.

"When we find those animals we find that they are frequently emaciated, don't have seagrass in their stomachs," Dr Playford said.

"They are mostly dying from natural causes, from diseases, although there are some boat strikes and netting impacts."