The sea creatures washing up on beaches that could prove fatal for pets

Beachgoers are being warned to keep a close eye on their dogs after two toxic sea creatures were spotted washed up on a Western Australian beach.

Perth resident Jo Robertson was at Whitfords Beach at around 5am on Monday with her dog when she noticed what was believed to be a black sea hare marooned on the sand, while seeing another by the water's edge.

Ms Robertson said her dog's instinct was to go check out the 30cm long sea slugs before quickly retreating in fear.

“One was in the sea and our dog tried to have a look, and the sea slug let out purple ink... my dog came running out of the water, quickly," she told Perth Now.

One Perth beachgoer spotted two black sea hares during her morning stroll. Source: The West Australian/Perth Now

Murdoch University senior lecturer in veterinary emergency and critical care Dr Lisa Smart said the slug was most likely a black sea hare.

“If it is a black sea hare then it is potentially toxic towards dogs if they eat it, lick or rub their fur on it, because the toxins, we think, are in the secretions of the sea hare, so animals can be exposed just by licking the surface,” she revealed.

According to Dr Smart, black sea hares are most commonly spotted on southwest WA beaches following “mass mortality events” between January to April.

She warned pet owners to make sure their dogs avoid all contact with them otherwise symptoms such as vomiting, drooling, trouble walking and seizures could be triggered. She said in some extreme cases, contact could prove fatal.

The two sea hares were discovered at Perth's Whitfords Beach. WA beaches are prone to appearances from black sea hares between January and April. Source: Instagram/

“The toxicity can start to take effect within a couple of hours but it can also take up to 12 to 18 hours for symptoms to be apparent as well, so it is a very variable onset,” Dr Smart said.

Dr Smart advises anyone who believes their pet may have touched a sea slug to seek veterinary advice immediately.

What are black sea hares?

Aplysia vaccaria, more commonly known as the black sea hare, are the largest sea slug species and can grow up to one metre in length.

The species eats brown seaweeds and kelp giving the animal its dark complexion, according to the California Academy of Sciences.

Black sea hares have a soft body, a small internal shell and large 'wings' or parapodia, which can be used for swimming.

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