Sea slugs have washed up along parts of Western Australia's southern coastline, prompting toxicity fears for water users and their pets, while algal blooms are also bringing a foul smell to the area.

Shire of Augusta Margaret River co-ordinator of landcare/environment John McKinney told NCA NewsWire a large species of sea hare had been washing ashore along the Augusta coastline and lower parts of the Hardy Inlet since February 10.

The sea slugs have been washing up for weeks. Picture: Shire of Augusta Margaret River
The sea slugs have been washing up for weeks. Picture: Shire of Augusta Margaret River

He said it was a regular occurrence in late summer but the numbers this year seemed higher.

"Numbers of the animals on the beaches are fluctuating daily with tide, swell and wind conditions, although dying and freshly deceased animals, along with partially decomposed animals, appear to be coming ashore every night," he said.

"The shire understands that in certain circumstances some species of sea hares can be toxic to dogs and has erected signage at key locations throughout Augusta to advise dog owners to be vigilant."

Dead sea slugs can be dangerously toxic. Picture: Shire of Augusta Margaret River
Dead sea slugs can be dangerously toxic. Picture: Shire of Augusta Margaret River

The Department of Primary Development and Regional Development has collected samples from the animals and nearby waters for analysis.

But Mr McKinney said removal of the sea slugs was not being considered because they covered a large area and were washing up daily.

Mr McKinney said there had also been reports of algal blooms along the coast in recent weeks, including in Augusta and Gracetown, although it was not believed to be related to the sea hares.

"This algal species can produce a very fishy smell when decomposing and it is believed that a combination of decomposing algae, seaweed and potentially sea hares is responsible for a reported smell," he said.

Sea slugs have washed up on beaches in Western Australia’s south. Picture: Shire of Augusta Margaret River
Sea slugs have washed up on beaches in Western Australia’s south. Picture: Shire of Augusta Margaret River

DPIRD warns people should not fish or swim in areas with large numbers of dead and decomposing fish because they may contain high levels of bacteria and smell bad.

Pets should also be stopped from coming into contact with dead or decomposing fish.

"Anyone who has handled dead or dying fish and experiences any inflammation on their hands around any cuts or abrasions should see a doctor," DPIRD said.

Originally published as Gross beach pic that'll creep out swimmers

Sea slugs are covering a large area of the coastline. Picture: Shire of Augusta Margaret River
Sea slugs are covering a large area of the coastline. Picture: Shire of Augusta Margaret River


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