A note on the button shells fishery in Kakinada Bay

Abstract

Umbonium species commonly called as 'button shells' are the smallest gastropod shells under the family Trochidae and subfamily Umboninae. They are also known as 'button top shells' or 'button snails'. They come in vast array of colours, in shades of grey, brown, olive green, pink, red, yellow or even white, almost uniform or with different axial and/ or spiral patterns. Even in single species various colour and patterns can be seen. They are distributed in the Indo-West Pacific regions where they lie burrowed in the shallow, soft and sandy bottoms. They occur in high densities and the individuals are usually very active. They feed on detritus and algae, sometimes depending on filter feeding unlike other snails. When confronted by predators they bury into the sandy bottom using their long foot or float into the water column to escape. They are non-edible ornamental gastropods that have high demand in the ornamental shellcraft industry.