Lugworm cast

Lugworm cast ©Julie Hatcher 


Scientific name: Arenicola marina
Have you ever seen those worm-like mounds on beaches? Those are a sign of lugworms! The worms themselves are very rarely seen except by fishermen who dig them up for bait.

Species information


Length: 12-20cm

Conservation status


When to see

January to December


Lugworms live in burrows in the sand both on the beach and in the sandy seabed. Their burrows are u-shaped and are formed by the lugworm swallowing sand and then pooing it out, creating wiggly piles of sand along the shoreline. These are known as casts. They feed on tiny animals and dead matter that are filtered through the sand they eat. They make a tasty snack for birds like curlew and godwit.

How to identify

When the tide goes out, coiled 'casts' can be found at the tail end of lugworm burrows. Look out for a small depression in the sand at the head end where the worm has ingested the sand. The worms themselves are variable in colour from black or brown to pink or green.


Found on sandy and muddy shores all round our coasts.

Did you know?

There are 2 species of worm on our shores referred to as the generic "lugworm": the Blow Lug and the Black Lug. The Black Lug is a different species and - as its name suggests - is black in colour.

How people can help

The Wildlife Trusts are working with sea users, scientists, politicians and local people towards a vision of 'Living Seas', where marine wildlife thrives. Do your bit for our Living Seas by supporting your local Wildlife Trust or checking out our Action pages.