PKOGRESS IN BIOLOGICAL INQUIRIES, 19 2 7 205 



present method of tagging. Beginning in October, 1927, therefore, 

 certain fish were tagged on the lower jaw, in a place where the 

 tag penetrates between the dentary and articular bones. It is thus 

 held rigidly and can not drop off as the result of softening and 

 wearing away of the tissue, as happens in the case of the tail. Un- 

 fortunately, the jaw bones of large cod grow so close together that 

 a tag can" not penetrate, so that this method is confined chiefly to 

 fish less than 30 inches in length. 



The outstanding results of the fish tagging up to December, 1927. 

 were as follows : 



Nantucket Shoals.— This has been one of our most important tag- 

 ging grounds each year from 1923 to 1927. Each fall the cod here 

 have migrated to the shore waters of Khode Island, Long Island, 

 and New Jersey. Many have been recaptured in the Chatham 

 Ground-South Channel region, but only stragglers have been re- 

 ported from north of Caj)e Cod or on Georges Bank. A large pro- 

 portion of the fish were recaptured on Nantucket Shoals (where they 

 were tagged) one or two years afterwards. 



Cholera Bo.nk, N. Y. — The first cod-marking in the present investi- 

 gation, west of the New England States, took place on this bank 

 November 14 to 21, 1927, when 166 fish were tagged. This was done 

 to learn something of the cods' movements after they had migrated 

 here in the fall from the grounds off southern Massachusetts. Four 

 of these cod had been reported recaptured up to the end of Decem- 

 ber, as follows: November 17, Jones Inlet, N. Y. ; November 21, 

 Bradley Beach, N. J.; December 11, Ambrose Channel Lightship, 

 N. Y. ; December 26, Easthampton, N. Y. The recapture made off 

 Easthampton is of particular interest, for it is the first evidence 

 obtained showing that some cod that migrate to western Long Island 

 in the early fall return eastward before the end of the year. 



Stellwagon Bank, Massachusetts Bay. — A few cod have been 

 tagged here each year since 1923 (except 1926), the total being 156; 

 of these, two were recaptured off Cape Ann, two off Rockaway, N. Y., 

 and one off Atlantic City, N. J. There is an indication, therefore, of 

 a migration both north and south of Stellwagon. 



Portland to Boothhay Harhor., Me. — Cod were tagged within this 

 sector from 1923 to 1925. As has been stated in a previous report, 

 most of the recaptures were local, but a few tagged cod migrated 

 offshore to Jeffreys Ledge and Platts Bank, while one each was taken 

 at Dennis (southern Massachusetts), Stellwagon Bank, and Grand 

 Manan, New Brunswick. 



Platts Bank. — Cod were tagged on this bank each year since 1923, 

 with the exception of 1926. There have been recaptured 19.2 per cent 

 of the 218 cod tagged in 1924 and 19.3 per cent of the 604 tagged in 

 1925. All of the 159 recaptures were taken locally except nine, which 

 migrated, one each to Harpswell, Me., Chatham, Mass., Nantucket 

 Shoals, and South Channel; there were two each to Cashes Ledge 

 and Jeffreys Ledge. On the basis of these returns, very little migra- 

 tion from Platts Bank was noted, although local intensity of fishing 

 must have been great. 



No cod were tagged on Platts Bank in 1926, and when fishing was 

 resumed there in 1927 it was found that fish were very scarce. In- 

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