56 MUSSEL CULTURE 



of growth will be, and therefore a hard and fast 

 statement cannot be made. 



Taking Scotch beds collectively, however, we 

 are inclined to estimate that the mussel when 

 placed in the favourable estuarine localities in- 

 dicated above, reaches a size suitable for bait, i.e. 

 about 2 inches, in about three years. In less 

 favourable positions, where the mussels are long 

 uncovered, and therefore kept without food and 

 free respiration, or are in pure sea-water, and in 

 rather exposed shores, the time taken to reach the 

 size indicated appears to vary from four to eight 

 or ten years. 



The mussel will grow on almost any natural 

 sea or estuarine bottom, but the rich flats, where 

 sand and gravel are covered by mud charged with 

 diatoms, infusoria, spores of algae, and other 

 vegetable matter, rear large fat mussels most 

 quickly. 



The natural enemies of the mussel are the star- 

 fish or cross-fish, and the whelks. The havoc 

 which can be done by inroads of these creatures is 

 astonishing. In the evidence given before the 

 Mussel Commission, three instances occur where 

 entire destruction of beds is attributed to star-fish, 

 and one instance in which it is traced to whelks. 



