420 BULLETIN OF THE BUREAU OF FISHERIES 



stripping, and the locality of liberation was at a considerable distance from their 

 normal spawning ground on Nantucket Shoals, hence it is a question how closely 

 their travels represent those carried out by fish spawning there naturally. How- 

 ever, the results were so consistent, one with another, as to warrant the working 

 hypothesis that at least a part of the great body of fish spawning on the shoals 

 works westward along the shores of southern New England during the late winter 

 after they have spawned out, returning again by the same route in spring, many of 

 them to revisit Nantucket Shoals and some to enter the Gulf of Maine, for recoveries 

 were made off Chatham and rumors of tagged fish were received from Maine and 

 Nova Scotia. The fact that one tagged cod was recaptured off Cape Judith, R. I., 

 in a spent condition during the second May after its release, that is, while returning 

 from its second migration to the southward, also corroborates this. 



Further investigations along this line promise such interesting results from the 

 fisheries standpoint that between 7,000 and 8,000 cod were tagged and released by 

 the Halcyon on Nantucket Shoals from April to October, 1923. Up to January 24, 

 1924, 163 of these fish had been recovered, and the locahties of recapture corrobo- 

 rate in a striking way the, westerly winter migration just outlined, for one fish was 

 reported from New Jersey in October, and during November, December, and 

 January 48 were reported from Rhode Island, Long Island, and New Jersey. 



Other interesting features appearing from the reports so far received are that 

 most of the fish appear to have remained all summer within a very few miles of the 

 spot on Nantucket Shoals where they were tagged and released, because all the summer 

 recoveries (107) were from that region, except for a few off Cape Cod and off Cape 

 Ann and the one New Jersey fish just mentioned, the most striking instance of this 

 being fish No. 231, tagged on the Shoals June 28, recaptured by the Halcyon close 

 by on October 3, and again on October 15. Apparently no migration to the east- 

 ward took place dm-ing the summer, because not a single fish was recaptured on 

 Georges Bank, notwithstanding the intensive fishing carried on there. 



The fact that cod may carry out extensive journeys (the larva? involuntarily, 

 but the adults under some directive stimulus, sexual or feeding) raises the 

 possibility that the maintenance of the cod stock of the Gulf of Maine depends as 

 much on immigration around Cape Sable as on the reproduction that takes place 

 locally (p. 422), productive though the latter may be. This whole question — 

 and especially the routes followed and distances traveled by the larvae while afloat — 

 is one of the most interesting problems now facing the Bureau of Fisheries in its 

 study of the natural history of North Atlantic food fishes. 



Rate of growth. — So far as we are aware the growth of cod fry for the first few 

 months after hatching has only twice been followed by direct observation in America. 

 The first observations were made in 1898, when a large school of newl}' hatched 

 larvae was released in December at Woods Hole in the "eel pond" (a lagoon freely 

 communicating with the harbor and -svith a temperature about paralleling that of 

 the outside water), where they grew to an average length of 50 to 100 nmi. by the 

 following June.'* The experiment was repeated in the winter of 1899 *° with similar 



" Bmnpus. Science, new series. Vol. VIII, 1898, p. 852. 



»« Smith. Bulletin, United States Fish Commission, Vol. XIX, 1899 (1901), p. 307. 



