94 



THE SCALLOP FISHERY 



is no reason to believe that this difficulty cannot be overcome by the 

 construction of improved pens, and by requisite care in cleaning. On 

 the other hand, as is stated in chapter VI., under " Artificial Culture," 

 scallop culture can only be successfully conducted in inclosed bodies of 

 water, since the expense of erecting pens would offset the profits. 

 Pens should merely be used to hold the immediate catch for market and 

 rarely utilized for rearing purposes. 



Penned and Unpenned Scallop Growth in 1906. 



(b) Results from Artificial Groivth.--The greater part of the points 

 enumerated in this chapter were obtained from the experiments upon 

 confined scallops, which, although merely approximating natural condi- 

 tions, were the only means available for arriving at definite conclusions 

 upon the growth of the scallop. For comparative work and as supple- 

 mented by definite observations on the natural beds, they proved of 

 great value in respect to the following: (1) length of life; it was neces- 

 sary to confine the scallops to ascertain the duration of life, which 

 results were supplemented by use of tagged and unconfined scallops; 

 (2) the growing months and the relative economic value of each month, 

 mainly determined from the pen experiments at Monomoy; (3) the 

 comparative rate of growth of the different sizes, determined from pen 

 and cage experiments; (4) growth during the spawning season; (5) 

 the effect of environment and natural conditions which affect the rate 

 of growth, resulting from (a) currents. (&) soil, (c) eel grass, (d) tem- 

 perature; (6) density; (7) depth of water. These were determined by 

 a comparison of the natural conditions for each pen and the effect 

 which each had upon growth. 



Among others, the following facts have been demonstrated by arti- 

 ficial growth experiments : 



(1) Scallops transplanted to Waters North of Boston.- -Three pens 

 were planted in May, 1906, two of these in the Essex River and one in 

 the Annisquam River, with scallops brought from Cape Cod. Unfortu- 

 nately, no records could be obtained as the pens were swept away by 

 the swift tidal currents of the north shore rivers, and no trace of the 



