Common Whelk

• In each egg mass only a few embryos are ever born: the first to develop devour their siblings and the unfertilised eggs before emerging.
• The masses of empty capsules that turn up on the shore were known aboard ship as sea wash balls, because sailors used them to wash their hands.
• It lays its eggs in spongy masses of capsules that the tides wash up on the beach; they are known as sea wash balls, because sailors used them to wash their hands.
• Only a handful of tiny snails emerge from each capsule: the first embryos to develop eat their siblings.
• It is extremely sensitive to the tributyltin in antifouling paints. That compound causes imposex, the development of male organs in females, which in severe cases sterilises them and wiped out whole North Sea populations. It was one of the pieces of evidence that led to the TBT ban.
• It locates carrion at a distance by smell, orienting itself with its siphon.
• It is an important fishery resource in the United Kingdom, France and Canada, much of it exported to South Korea.

Skeleton type

Invertebrate - external calcareous shell (mollusc)

Habitat and environment

Sandy, muddy and gravel bottoms of the North Atlantic, from 0 to 1,200 m

Sexual maturity

5-7 years

Sources consulted: Linneo (1758) · Marine Life Information Network · Mensink et al. (1996) · Organización Marítima Internacional · ScienceDirect (Hughes 1989) · Science Advances, How colonial animals evolve · Wikipedia, Zooid · anatomia de Gastropoda