They are somewhat remote from the sea mussels in structure, and have not even a common economic importance.
The sheltered waters of the broken southern coast, however, are rich in fish and molluscs, especially in mussels, limpets and barnacles, which are the principal food resource of the nomadic Indian tribes of those regions.
Such movement is more frequent in young mussels than in the full-grown.
The annual value of the shell-fish (lobsters, crabs, oysters, mussels, clams, periwinkles, cockles, shrimps) is about £73,000.
These cod are fed chiefly on mussels, and when the keeper approaches to feed them they may be seen rising to the surface in hundreds and eagerly seeking the edge.