REPORT OF COMMISSIONERS OF INLAND FISHERIES. 83 



VI. The Continued Investigation into the Methods .of Clam 

 Culture. 



During the past year little work has been done in the way of new 

 experiments or actual clam culture. The condition of the clamming 

 territory, however, has given an opportunity to make many observa- 

 tions which, taken together with our previous experiments in clam 

 culture have an important bearing on the question of the future 

 development of a clam industry in Rhode Island. 



The effect of digging over clam beds was mentioned in the last 

 report. The statement that the digging over seemed to render the 

 soil unfavorable for the establishment of a new set has had new 

 support in the condition of the set at Greene's Island. The extensive 

 digging attendant on a previous large set apparently prevented the 

 Island from receiving its share of the abundant set of 1904. The 

 old set was therefore gradually dug out, and in 1906 little digging 

 was done on the Island. Consequentl}^ there was a good set on the 

 Island this year, while other shores which were constantly dug over 

 received a very meager set. 



The slow growth of clams in the overstocked beds has also been 

 noted during the past two pears. Clams which on account of age 

 should have been three inches or more in length, are on the average 

 barely two inches long. In places where the tide runs swiftly this 

 retarding of growth can not be regarded as due to a lack of food, but 

 is apparently attributable to interference with the burrowing and 

 feeding. 



When living in the water uncovered by soil, clams will grow quite 

 rapidly for a short time and then very slowly. 



Such small clams, whose thick shells indicate a considerable age, 

 are often seen on the timbers of wharves where they are held in place 

 by mussel threads or by their own byssus. A certain depth of soil 

 is necessary for a favorable growth of a clam, as has been ascertained 

 from experiments with clams grown in boxes with various depths of 

 soil. In the overcrowded beds, however, the majority of the clams 



