Laver Spire Shell
(Hydrobia spp)

Hydrobia on Sea Lettuce

Hydobia is a tiny snail, 3-6 mm in length. They may be extremely abundant and be found at the top of the sheltered, muddy, seashore in huge numbers. There are several different species all quite difficult to identify.

Although small they may dominate the mud in estuaries by their huge numbers - 9000 per metre square. Unlike most marine and seashore molluscs they originated from freshwater and are very tolerant of low salinity. In late summer, as the densities rise they secrete a mucus raft which will carry them floating on the water surface. In this way the tide disperses them across the mud, usually with their egg capsules. Often this precarious form of dispersal sweeps them out to sea or on to the strandline where they die in millions. The food varies from diatoms and detritus to bacteria on the bare mud. Despite their small size they are the principle food of the Shelduck and also the Ringed Plover

Typical of estuaries and mudflats where they can be found in the surface of the mud. Well distributed over most Atlantic estuaries.