82 THE SCALLOP FISHERY 



usually being covered with numerous growths, both plant and animal, 

 which may obscure the line. 



As the formation of the annual line is due to cessation of growth 

 during the winter, it logically follows that any check for a less or 

 greater time will cause slight lines, which are entirely distinct from the 

 annual growth line and are by no means as prominent, being merely 

 heavier concentric layers. Growth lines of this sort can be produced 

 on young scallops at any time by interfering temporarily with their 

 growth. The same scallops repeatedly transferred from the spat boxes 

 on the raft at Monomoy Point, and kept in an aquarium for even as 

 short a period as one day, could be made to produce as many as three 

 or four distinct growth lines. Large '' seed " scallops and even adults, 

 when transplanted from Harwich and Chatham to Monomoy Point, 

 always showed the change by the formation of a line of growth. 



The growth line is not caused by the spawning season, as has been 

 supposed, since our investigations upon the effect of the spawning on 

 growth indicate that there is no cessation during this period (June 

 and July), and that before the beginning of the spawning thpre has 

 formed during the month of May about % of an inch of new shell. 

 AU our observations for the years from 1906 to 1909 have shown that 

 the new growth begins about May 1, except for the variation of differ- 

 ent years, and that the growth line is formed at a time previous to the 

 spawning season. 



Although the growth line appears when the scallop is but ten months 

 old, it can for all practical purposes be considered as marking the first 

 year of the scallop's life. While the spawning season is not completed 

 until about the first part of August, these dates are included in the 

 closed season, which lasts from April to October, and in a general sense 

 the growth line can be associated with the spawning season, and in the 

 open fishing season any scallop with the annual growth line is ready 

 for capture. Risser (2) was the first to advocate the use of the growth 

 line to distinguish the difference between the adult and " seed," while 

 the Commonwealth of Massachusetts was the first to put into force a 

 law based on the growth line as distinguishing the adult from the " seed " 

 or immature scallop, which has not spawned. While we cannot say 

 that every scallop with a growth line has spawned, we can definitely 

 state that every scallop without a growth line has not spawned and is a 

 " seed " scallop. The growth line has thus proved of great practical 

 importance in scallop legislation, which is based on the facts obtained 

 upon the length of life and spawning of the scallop in Massachusetts 

 waters. 



Growth during Spawning Season. — The spawning season has the 

 wide limits from June 15 to August 15. The gTeater part of the spawn- 

 ing is accomplished during June and the first part of July. Corre- 

 sponding to the spawning period there occurs a slowing in the rate of 



