COD EGGS IN MASSACHUSETTS BAY, 1924-1925 



255 



in the natural economy of the region. It had been suggested that the southwest 

 current or drift along the Maine coast carries eggs and early fry into Massachusetts 

 Bay, which, protected by the arm of Cape Cod, serves as a nursery not only for those 

 entering from the east but also for large numbers spawned in the bay itself, where the 

 young cod find ample food and are protected from storms and winds until large 

 enough to take care of themselves. It had even been suggested that this area might 

 form an important source of supply for the codfish of the whole coast of New England. 



PREVIOUS EVIDENCE OF COASTAL DRIFT IN THE GULF OF MAINE 



That a definite southerly drift or set exists along the whole western margin of 

 the Gulf of Maine is indisputable. Since earliest times fishermen have known of the 

 "so'west current" and utilized it in navigation. At times its inner margin is defined 

 clearly by slicks or, on calm days, by a line of seaweed and other floating debris. 



Drift-bottle and current experiments by Mavor (1920 and 1922), Bigelow (1927), 

 and Dawson (1905) have shown not only the direction of the drift but also have 

 contributed considerable information on its rate of movement. (See fig. 1.) Mavor 

 found that the set in summer and autumn averaged about 4 miles per day, and 

 Bigelow (1926) suggests that in spring it is probably higher than that. To the drift- 

 bottle evidence may be added the very extensive data on the general circulation 

 obtained by the latter author from current measurements, temperature and salinity 

 distribution, and dynamics, all of which substantiate the existence of a definite 

 counterclockwise set around the gulf. 



Earlier observations on egg and larval-fish distribution also indicate a movement 

 from the northeast to the southwest. Based on evidence accumulated in the Gulf of 

 Maine since 1912, Bigelow (1926, p. 75) concluded: '"'Thus fish eggs and larvge, and 

 for that matter every member of the plankton, animal or vegetable, tend to follow 

 the same peripheral migration zone as do the immigrants that enter the eastern side 

 of the gulf in the upper 50 meters." Also, "At the times when the dominant drift of 

 the surface water follows the coast line closest, south toward Cape Ann, Massachusetts 

 Bay probably acts to some extent as a catch basin for all sorts of flotsam from the 

 north, living, of course, as well as dead, as it did for certain of Mavor's drift bottles. 

 The chart (fig. 2) suggests that larvse that pass Cape Ann tend to be caught up in the 

 backwater of the bay, to remain there until they abandon the pelagic life for the 

 bottom. Thus it is probable that the rich fish fauna of the bay and its adjacent 

 waters is regularly recruited from the north and east." 



The scarcity of eggs reported by Bigelow in the Gulf of Maine east of Mount 

 Desert and the increasing numbers toward the west, combined with the fact that one 

 of the most important of the inshore spawning grounds (Ipswich Bay) is situated 

 just north of Cape Ann, seemed to be assurance in itself of an ample supply of develop- 

 ing eggs and pelagic fry, even if no breeding grounds had existed within the confines 

 of Massachusetts Bay itself; but catches extending over a long period of years from 

 the grounds off Plymouth have shown that this bay harbors one of the largest of the 

 inshore breeding centers and one that supplies a large percentage of the eggs hatched 

 each year at Gloucester. Between November 24, 1911, and January 3, 1912, 67,032,- 

 000 cod eggs were collected from Plymouth by the Gloucester hatchery; and in 1925-26 

 these same grounds were one of the principal contributors to the 1,219,468,000 cod 



