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Lugworm cast

Lugworm cast ©Julie Hatcher 

Lugworm

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.

Scientific name

Arenicola marina (Blow Lug) and Arenicola defodiens (Black Lug)

When to see

January to December

Species information

Category

Statistics

Length: 12-20cm
Common

Habitats

About

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.

Distribution

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 "lugworm": the Blow Lug and the Black Lug, which you can tell apart from their casts. The Black Lug produces a tightly coiled, neat cast with a depression in the middle whereas the Blow Lug produces a messy cast with a small depression separate to the cast (pictured above).