Colin Weir was about to take a swim at Bilgola, a suburb of Sydney, when he noticed a large number of tiny maggots in an ocean rock pool on Tuesday, January 30.

The pool was closed by the Northern Beaches Council after a woman found wriggling maggots inside her swimming costume following a dip, news.com.au reported. The council’s manager of environment and infrastructure told the Manly Daily the infestation had started in seaweed, which later washed into the rock pool.

On January 31, Beachwatch NSW said a “large number” of kelp fly maggots was found on Dee Why Beach, while an infestation was reported at Newport. Credit: Colin Weir via Storyful