PROGRESS IN BIOLOGICAL INQUIRIES, 1926 523 
Exclusive of the Woods Hole fish, 40,097 cod, pollock, and haddock 
have been caught and tagged at sea from 1923 to 1926. A complete 
statistical summary follows: ¢ 









Item | 1923 1924 1925 1926 
| 
IN DF Pay PLS) (EL ER CUES oe ii ee RS he SS ee | 7 9 16 4 
aystonactuslunahing: 2 Sins). es saa eo ee sess 5 kee. 43 51 76 23 
EUS RACLUA NSM NG a ane oe soe Se eats cana a nsancccocne 333 318.5 461 167 
INTENDED OPCOG WAGROU ous oo ea aes oes nae sane wase ena nssaseee 7, 618 | 6, 209 10, 420 3, 565 
Number of poles (nett (0 ae ee Se eee en ee a | 2, 215 916 949 39 
Nin DEL OhNAOOUCKLOPEOUS=.) nc oc tnna- heen Saoccet-cuccstoce 411 | 3, 223 | 3, 891 641 
otalmumiperionfishtapged.. ..2- 2-4. 2e sehen eases 10, 244 | 10,348 | 15, 260 | 4, 245 
Average number of fish tagged per day.------..-.---------- 238 | 203 201 | 185 
Average number of fish tagged per hour___._._-_._.-..----- 30. 76 | 32.5 88:1 | 25.4 
i 

According to localities, the number of fish tagged is divided as 
follows: 




Item 1923 1924 1925 1926 
ifassachusetts, south of Cape Cod... 222-222 5. na oe eee eee» 10}'231 4, 384 6, 143 1, 730 
Massachusetts, north of Cape Cod__..-.....-..-..----.---.---- 13 163 314 | 0 
ING WE amp ShITen as se sae cee ee Se ee eee ee 0 8 5 | 0 
Vici ra Oe nee eS OE es re Rk ce Se Ee 0 5, 793 8, 798 1, 412 
CROTPes Banks ssa s eae REE ke eee eS | 0 0 0 1, 103 

The total number of recaptures up to December 31, 1926, amounted 
to 1,940 and consisted of 1,742 cod, 72 pollock, and 126 haddock. 
Scale samples were taken from all fish tagged in 1926, as well 
as during 1924 and 1925. All the samples taken during 1924 (over 
10,000) have been mounted and about 1,000 have been studied. 
Although tagging operations during 1926 were not as extensive as 
during the preceding three years, some very instructive results were 
obtained. It is believed that the year 1927 will produce results of 
great interest to this investigation, for not only is it planned to 
operate on an enlarged scale, but many of the experiments begun 
during the preceding four years will be one year nearer completion 
and in some cases may be terminated successfully. The outstanding 
results of the investigation during 1926 are as follows: 
1. On the one cruise made to Nantucket Shoals (September 5-11), 
it was found that the stock of cod differed considerably in size from 
the fish present there during the period from the beginning of the 
investigation in 1923 up to 1925. Heretofore, cod less than 18 inches 
in length were caught rarely, and 22 to 32 inch fish predominated ; 
but in 1926 large fish were scarce, fish below 18 inches were common, 
and the predominating sizes were 16 to 22 inches. Some intimation 
of this exodus of large fish and entry of small fish was had in the 
preceding fall and could be traced to August, 1925, when the bottom- 
water temperature was 15° C, (59° F.) and the cod were much 
scattered and bunched. How unusual this high water temperature is 
can not be known until the investigation has continued further. 
In each of the tagging years (1923, 1924, and 1925), a definite 
migration of tagged cod occurred from Nantucket Shoals to the 
waters between Rhode Island and southern New Jersey. As the 
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