180 BULLETIN OF THE BUREAU OF FISHERIES 



Cod out across the western end of Georges Bank, with frequencies of from less than 

 10 to nearly 3,000 specimens per square meter, averaging o% per cent of the copepods 

 taken in these vertical hauls. In the year 1915 it was not detected anywhere in the 

 gulf in May or during the first three weeks of June, though vertical hauls were made 

 at 20 stations during that period, but on June 26 (station 20099) it was taken at the 

 rate of 430 per square meter in the western basin, and it figures in the lists (p. 298) for 

 two August stations. In September it occurred in all the vertical hauls in the coastal 

 zone from Cape Cod northward and eastward toward the mouth of the Bay of Fundy, 

 as well as on German Bank (80 per cent of all the stations for the month), averaging 

 4,490 per square meter where the vertical net took it. 



During the first half of October, 1915, it continued universal along the coastal 

 zone from off Cape Cod to the neighborhood of Mount Desert Island (six stations), 

 varying in abundance from 1,140 to 14,225 per square meter (average about 5,600). 

 It also occurred in two out of three vertical hauls over the shelf south of Marthas 

 Vineyard on the 22d (stations 10332 and 10333), frequencies of about 6,000 and 

 4,000 square meters. By the last week of the month it seems that it had vanished 

 from the Massachusetts Bay region, for not a single specimen was detected at 

 four stations there; but this can not be interpreted as a regular seasonal change, 

 because it was taken at all the stations within 15 to 20 miles of land, from off Cape 

 Cod to the mouth of the Bay of Fundy during December, 1920, and January, 1921, 

 averaging about 5.5 per cent of the copepods and 10 to 15 per cent of the extremely 

 sparse community at the mouth of Massachusetts Bay and off the Isles of Shoals 

 (stations 10489 and 10493), though not found at any of the four stations farther 

 out in the basin. 



It is not clear from the data just outlined whether A. longiremis has two sea- 

 sonal maxima in the gulf, one in late spring, another (much more pronounced) in 

 early autumn, separated by a period of a month or more during which it nearly 

 or quite disappears, as the records for the two years 1915 and 1920 suggest; or 

 whether it followed different seasonal cycles during the two years, multiplying from 

 April on in 1920, but not appearing at all until June in 1915. In either case it 

 clearly attains its maximum abundance in the gulf during the warm half of the year. 

 It is never more than a minor factor in the plankton except when all other species 

 of copepods are very scarce, and never occurs in numbers that would be called large 

 for other more important copepods, 14,265 per square meter being the highest 

 frequency yet recorded for it east or north of Nantucket. A. longiremis, like A. 

 clausi, contracts its range to the shoaler waters of the gulf during the cold half of the 

 year, including the offshore banks as well as the coastal zone. When its numbers 

 increase, its area of occurrence spreads out over the deep basin of the gulf, but we 

 have not taken it outside the continental edge. 



That A. longiremis is endemic in the gulf is proved by the presence of numerous 

 juveniles, together with adults, at the one August station already mentioned (p. 

 177). This, however, does not forbid the possibility that its numbers are recruited 

 by immigration as well as by local propagation. On the average, A. longiremis 

 was relatively more important in the catches at the surface than in the vertical 

 hauls in March and April, though not in May, as appears in the following table of 

 its percentage in 1920, counting only the stations at which it occurred: 



