50 
BULLETIN OF THE BUREAU OF FISHERIES 
LENGTHS OF NANTUCKET SHOALS COD IN 1923 
On all the grounds fished by us during 1923 very much the same frequency 
distribution was obtained, indicating that one school of cod covered a good part of 
the shoals. It was not until October that on one of the tagging grounds the length 
distribution was altered somewhat by the appearance of a body of small fish (fig. 15, 
No. 1, symbol B ) which had not been noted from April to September. The A fish 
centered around 26 to 28 inches on all the grounds and at Great Rip the 29-inch size 
was included in addition. 
The fact that the length-frequency distribution of the Nantucket Shoals cod 
remained rather constant throughout the summer of 1923 suggests that relatively 
few immigrants arrived during that season, else the frequencies would probably 
have altered materially. And as the catch of fish taken by the Halcyon per unit of 
effort did not fall during the summer, it appears that the emigration of Nantucket 
cod to the Chatham-South Channel region, already referred to, involved a relatively 
small part of the population. 
Figure 15. — No. 1 =length-frequency distribution of 1,144 eod caught at Round Shoal buoy June 22-28 (solid line), and 1,071 
caught October 3-6, 1923 (broken line). No. .8=lengtk-frequency distribution of 788 cod caught 5 to 12 miles ESE.of 
Round Shoal buoy July 14-16, 1924 
LENGTHS OF NANTUCKET SHOALS COD IN 1924 
The first cruise in 1924 was not made until July. Two localities were fished 
at that time, namely, the Round Shoal buoy grounds where we tagged throughout 
1923 and a new tagging ground situated 5 to 12 miles east-southeast from this buoy. 
We noticed at once that the lengths of the cod taken in July, 1924, differed con- 
siderably from those obtained during any month or on any tagging ground during 
1923. (Figs. 15 and 16.) 
At Round Shoal buoy cod of the A group had disappeared, their place being taken 
by what can be recognized as the B group, now centering around 23 to 25 inches, 
evidently having grown to this size since the previous season when it was last seen 
at 20 to 22 inches. But on the new tagging ground, 5 to 12 miles east-southeast 
of Round Shoal buoy, however, the catch was dominated by the A group (fig. 15, 
No. 2), which had increased in length since the summer of 1923. Unfortunately, 
no tagging was done in 1923 on the grounds east-southeast from Round Shoal buoy; 
but it would seem that many of these A group fish had moved to there, as indicated 
by the recapture of the Halcyon, 12 miles east-southeast of Round Shoal buoy, of a 
