La Niña forcing sick turtles and dugongs to find food in Moreton Bay

Published 23 September 2022

Boaties are being urged to be careful on the waters of Moreton Bay, with weakened turtles and dugongs migrating south in search of food.

Seagrass beds around Hervey Bay have been wiped out, leaving the animals with only two choices: move away, or try eating something else.

Mayor Peter Flannery said already this week a turtle and a dugong had washed ashore on Bribie Island.

“Turtles and dugongs are the grazers of the ocean and need meadows seagrass to survive, which we usually have an abundance of here in Moreton Bay but our seagrass has also been flood damaged,” he said.

“So we’re seeing more animals moving into an area where there’s less food, which means they’re weak and often nearer to the surface unable to quickly move away from boats.

“We need boaties to keep an eye out, slow down, and be safe to avoid hitting these poor animals which are already weak and may not survive.”

Anyone who finds a stranded sea turtle is asked to call the QPWS marine stranding network on 1300 130 372.

Please do not put them back into the water, as it delays their ability to receive care.

UniSC Associate Professor Kathy Townsend said three major flood events had engorged the Mary River and dumped huge amounts of sediment into Hervey Bay, even worse than the flood impacts that hit Moreton Bay.

 “In normal years, sediment from rivers brings a flush of nutrients, which can actually cause a seagrass boom once the water quality improves,” she said.

“The problem is, there’s been just too much sediment.

“With one La Niña after another, it’s been harder for seagrass to recover or regrow.

“As sediment from the floods spread out over the shallow seas, it made the water murkier.

“Soon, sunlight couldn’t penetrate the gloom to reach the seagrass meadows.

“The result has been widespread devastation in the Great Sandy Straits region.

“Summers are when our seagrass meadows usually flourish, letting turtles and dugong fatten up for the winter. During winter, seagrass naturally dies back.

“Sea turtles in poor condition will not be able to migrate successfully, which means they’re heading for a poor nesting season.

“Dugongs, too, will struggle. Without stores of fat, the females won’t be able to support their calves through to weaning stage. That will make it harder to replenish the population and recover from losses from starvation or relocation.

“We won’t know the full impact of this event until years from now.”