Lugworm  (Arenicola marina)

This lugworm lives in burrows in the sediment at depths of 20-40cm (3). It feeds on organic matter in the sediment by drawing water into the burrow and filtering particles from the current (2).

The sexes are separate, and spawning typically occurs in late autumn and winter (3). Males release sperm, which rests in puddles on the sediment surface before being dispersed by the tide (2). Females release eggs into the burrow, where they are fertilised by sperm that is drawn into the burrow with the respiratory current (2). Initially, the larvae develop inside the burrow, they then crawl or swim to the sediment surface where they are dispersed by currents (2). The larvae settle on areas of sand or shingle and live inside mucus tubes attached to the sediment; after a few months these tubes detach, and the young worms drift in the water for a time before burrowing into the sediment (2). Sexual maturity is reached after around 2 years, and spawning occurs once a year. The average life-span of this worm is thought to be around 6 years (2). Although they are relatively safe within their burrows, this species is vulnerable to predation by flatfishes and birds, who crop the tail region of the worm as it deposits casts; the worm usually survives, although the growth rate may subsequently decrease (3).