92 
BULLETIN OF THE BUREAU OF FISHERIES. 
GROWTH. 
The rate of growth is dependent upon circumstances of situation, temperature, 
salinity of the water, and the amount of food available. Mussels in sheltered positions 
grow more rapidly than those exposed to the force of waves. The ideal location for the 
mussel is an estuary where food is supplied in great abundance, where the exposure to air 
between tides is not long, and where there is no deposition of silt. In such a place, if not 
too thickly crowded, they may grow to the average size of 2 or 3 inches in length in a single 
year. On the English coast, where they are cultivated by the bed system, it requires not 
less than two years and usually three years for them to reach a length of 2 inches. In 
France, where they are cultivated by the buchot method, that size is acquired in about 
a year and a half. O11 our Atlantic coast Charles H. Silverwood, of Pawtucket, R. I., 
says the mussels of Narragansett Bay reach marketable size, which I take to be not less 
than 2 inches, in from twenty-eight to thirty-four months. 
Overcrowding is a very important factor affecting the growth of mussels. A single 
pair produces myriads of young, most of which are doomed to early death through lack 
of space and other conditions necessary to growth. After the free swimming stage is 
over, the young mussels often apply themselves in such close proximity to each other 
that no space is left for increase in size. In order to grow it is necessary for the stronger 
to smother out the weaker competitors. Sometimes the death rate from this cause is so 
high that the many disintegrating bodies apparently contaminate the closely applied 
living individuals and cause their destruction. This process may go on so far as practi- 
cally to destroy what looks like a promising bed. Mussels on the margin of a thick 
cluster will almost always be found larger and in a more thrifty condition. Consequently, 
the healthiest individuals and specimens of largest size, other conditions being the same, 
are found in beds where the mussels do not lie in close contact with each other. 
FOOD. 
The food of the mussel is an important topic for study. A knowledge of the food and 
feeding habits of the marine animals which are utilized as food by man is of much greater 
importance than is ordinarily supposed. Especially is this true of forms like the mussel 
and oyster, which may be propagated by artificial means. The agriculturist who plants 
his grain regardless of the presence or absence of nitrates, phosphates, and sulphates in 
the soil is apt to reap very small crops. These chemical substances constitute an 
essential part of the food of plants, and the amount of the harvest’s yield depends 
largely upon their presence in the ground on which it grows. The important relation 
of soil composition to crop production is well known and is receiving very serious 
investigation in every State of the Union. 
The cultivation of marine products depends upon this same principle. The would-be 
oyster culturist who plants his seed oysters in any convenient spot, without knowledge of 
what constitutes their food or of its presence in the water, will be even less successful than 
