Researchers are alarmed at a dramatic decline in the population of little penguins on Penguin Island amid fears the trend could threaten the popular tourist attraction.
In the wake of unprecedented marine heatwaves off WA's south-west coast, experts have warned the collapse of the local population is a harbinger for broader problems of climate change.
Murdoch University research associate Belinda Cannell said the "anomalous" sea temperatures recorded over the past two years had driven away whitebait, the penguins' primary food source.
Dr Cannell, who has studied the penguins since 1994, said the slump had severely reduced the penguins' breeding success and largely driven a fourfold increase in their deaths.
Little penguins remained close to their colonies to feed their chicks each night, but this was being hampered by the lack of whitebait.
She said other explanations for the penguins' plight were more complex and probably included an increase in strikes from boat propellers as the number of people with pleasure craft soared.
According to Dr Cannell, the island's resident population of little penguins, with a smaller group on Garden Island, is the species' northernmost population and could disappear in 30 to 40 years.
"It is likely that we will see a real decline in the population over a shorter time scale, especially if La Nina conditions continue," she said.
With funding for her research into the penguins about to run out, Dr Cannell said she was seeking an extra $360,000 to complete her work into what was causing the decline.
Despite a funding commitment with the City of Rockingham worth $60,000 over three years and support from the Department of Environment and Conservation, Dr Cannell said the money was needed for things such as satellite tagging and monitoring.
Understanding what was happening to the penguins was crucial, she said, because they were a "sentinel" for WA's marine health.
She said climate predictions did not bode well for the colony.