PROGRESS IN BIOLOGICAIj INQUIRIES 43 



The outstanding results of the fish tagging to December, 1924, are 

 as follows: 



1. A definite and apparently extensive migration of cod from the 

 region of Nantucket Shoals, Mass., to the shores of Rhode Island, 

 Long Island, New Jersey, and possibly farther south, occurring late 

 in the fall. 



2. Many of the cod migrating to the south and west return to 

 Nantucket Shoals the following spring. 



3. The cod on Nantucket Shoals do not scatter to. various feeding 

 grounds during the summer, but appear to remain together from 

 spring to fall ; they were found to be very much localized, not only 

 here but in various localities along the Maine coast. Not only do cod 

 remain together in a general way, but small shoals of fish have been 

 found to remain close together for months at a time (June to Octo- 

 ber) and to have moved not more than one-quarter mile from where 

 they were tagged. There are numerous records to prove this. 



4. Not many cod migrate from Nantucket Shoals to South Chan- 

 nel and very few go to Georges Bank from the Shoals. This result 

 was entirely unexpected, but upon a close examination of the facts 

 it was found that the plain, sandy bottom of South Channel is not 

 sufficiently attractive to the cod to lure them from Nantucket Shoals, 

 where conditions in many respects are ideal. South Channel is 

 principally a haddock ground, although many cod are taken there. 



5. The relation of water temperature to the movements of the cod 

 is not so well understood. At the present time it is thought that the 

 effects of temperature are not nearly as great as was supposed. What- 

 ever the influence, it appears to be indirect. It has been fairly well 

 determined that the water temperature (bottom) on the Cholera 

 Bank, N. Y., is as low as or perhaps lower than that of Nantucket 

 Shoals month for month throughout the year. Cod may be found on 

 the Cholera Bank from November to May, with none at all during 

 the summer, but they are found the year around on Nantucket 

 Shoals and are particularly abundant in the summer. There is, of 

 course, some reason why cod do not remain on the Cholera Bank 

 throughout the year, but this reason apparently is not the tempera- 

 ture. Many temperature records are lacking from these two local- 

 ities, but an effort will be made to obtain this information. 



FISHES OF THE SOUTH ATI^NTIC COAST 



The investigation of the fisheries of the South Atlantic jcoast, 

 which was begun late in the fiscal year 1924, has been continued by 

 Elmer Higgins, director of the Key West (Fla.) biological station. 



The shark investigations were continued at Big Pine, Fla. The ob- 

 ject of the investigation was to study the destructiveness of sharks to 

 commercial fisheries and to discover something concerning their bi- 

 ology which might have bearing upon their control should that prove 

 desirable. A month was spent in field observations at the shark fishery 

 of the Ocean Leather Co., and through tlieir courtesy many data 

 were collected bearing upon the natural history of the sharks com- 

 mon to that locality. Detailed descriptions of the seven species oc- 

 curring in the fishery at Big Pine in summer were obtained, includ- 

 ing many measurements of body proportions which will correct er- 

 56650—25 2 



