More than one quarter of Perth’s Little Penguin deaths are the result of being hit by boats and other watercraft, a recent report has found.
Researchers from three organisations, including two Perth universities, performed examinations on 159 Little Penguins that were found dead in the Perth region between 2003 and 2012.
They found 26 per cent of the penguins had suffered physical trauma, including lacerations, fractures of the bill, complete beheadings, and loss of flippers or feet.
All but two of the deaths caused by lacerations could be attributed to propeller strikes or the fins of windsurfers.
Murdoch University researcher Belinda Cannell, who co-authored the 2016 study, said watercraft posed a unique threat to penguins because the birds sit low (within the top metre) of the water where they cannot easily be seen. They also blend in on the surface when the water is choppy.
She said people using boats or and jet skis should slow down in critical nesting and feeding areas.
“The speeds that boats travel at are much faster than what penguins travel, so penguins can’t get out of the way,” Dr Cannell said.
She said it was important to educate people about the penguins because the birds could not choose to simply forage elsewhere.
“When raising chicks, they must remain within 25km of the colony if they are to return the same evening to feed their chicks,” Cannell said.
“… So, if there are increasingly more boats in the same areas that are used by the penguins, then the likelihood of impacts will be higher.”
Dr Cannell also said increased watercraft usage could affect the breeding populations on Penguin Island and nearby Garden Island.
“Whilst many of the penguins that die at sea will never be found, we assume that the proportions attributed to each of the causes of mortalities [in the study] will be similar for all mortalities,” she said.
“If the mortality of adults increases due to increased watercraft injury, then the local populations will reduce.
“This effect is exacerbated in years of reduced prey abundance when fewer penguins are breeding, but the effect will be delayed for 2-3 years.
“This is because young penguins leave their nest and don’t return to their colony until they are 2-3 years old when they start to breed.”
Dr Cannell said the second biggest cause of mortality was starvation, caused by the reduction of prey because of climate change.
The research is expected to be used in the development of management strategies.