Aerial surveys are being undertaken on the Kimberley coast to try to determine how many animals have died at the same location and time as a mysterious fish-kill.
Over the last 10 days hundreds of fish have washed up dead on a 10-kilometre stretch of coast on the Dampier Peninsula, north of Broome.
Parks and Wildlife has now confirmed nine turtles, 16 sea-snakes and four birds have also been found dead in the same area.
Wildlife officer Pete Carstairs said it was a distressing situation.
"It is disturbing with them being native animals, and some of them are endangered species, so it is alarming when they turn up on the beach dead," he said.
"But we are working towards a solution as to what the cause of the problem is and then we'll be able to investigate further and hopefully prevent further occurrences."
He said a helicopter was being chartered to visit the remote coastal area, to establish if there had been further deaths.
"We're looking to get a helicopter up to do a full survey of the coast and then we'll be able to determine what kind of numbers we're able to find," Mr Carstairs said.
"We've got some pretty skilled helicopter pilots able to do that, and they'll be landing on the beaches and then our staff will be looking for animals on the beach."
Algal bloom might be to blame
Locals are presuming the animals' deaths are linked to a large-scale fish kill reported a week earlier in the same area.
Hundreds of fish were found dead or dying on beaches popular for camping, swimming and fishing.
Initially the Department of Fisheries said an unusual combination of environmental factors might have been to blame, with on-shore winds, king tides and warm ocean conditions resulting in hot water being flushed across the offshore reefs.
But there is now evidence an algal bloom may be responsible for the deaths.
Fisheries regional manager Peter Godfrey said algae strands were found during ocean and aerial surveys done in the Manari area over the last two days.
"The bloom seems fairly stationary, adjacent to the area near Manari and Barred Creek, and it's not at this stage appearing to stretch any further north or south," he said.
"We've taken some fresh fish samples and samples of the slick, and they are being examined by a fish-health team at the moment to determine exactly what the algae is, and what the relationship is with the fish-kill, whether it's the cause of the fish-kill, or a symptom of the fish-kill, and how the two things are related.
"We're still cautioning people not to swim in the area of an algal bloom, or to eat or collect fish that have washed up on the beach."
Fish and water samples are being tested at laboratories in Perth and the eastern states.
It is hoped examinations of the dead animals will help confirm the cause of death.
