Imposex in dog welks

What is it: 

Imposex is the development of male sexual characteristics (the formation of a vas deferens and growth of a penis) in female dog whelks. The common dog whelk, Nucella lapillus, is a marine snail. It is abundant on many rocky shores, where it feeds on barnacles.

Links to Scotland's Marine Atlas: 
This information page is part of the theme: 
Imposex in dog whelks © SEPA
Imposex in dog whelks © SEPA