Preliminary Survey of the Littorina littorea (the Periwinkle) in South-East and South Coasts of Ireland

Abstract

Of the three periwinkles Littorina littorea, Littorina saxatilis and Littorina littoralis only L. littorea, is of commercial value. The other two species are used mainly for decorative purposes and not for human consumption. Periwinkles are found on rocky shores and also on muddy intertidal zones which have a good cover of seaweed. They spend most of their existence in the intertidal zone below high water of neap tide and are found associated with the brown sea weeds such as bladderwrack (Ascophalium nodosum) and also the green sea weeds (Enteromorpha spp.). These weeds provide them with both shelter and food. Periwinkles browse on the sedentary animals which live on sea weed and on the weed itself. The investigations were confined to the size and quality of the periwinkles from Wexford, Waterford, Dungarvan, Youghal and Cork Harbours. The numbers per kilogram and the percentage meat yield were determined together with length frequency distribution.