186 BULLETIN OF THE BUREAU OF FISHERIES 



towings of 1912, 1913, and 1914 than in those of 1915 may simply have been a sea- 

 sonal phenomenon associated with the fact that in the first three years the Grampus 

 cruised in August, when Anomalocera is at its maximum, whereas in 1915 most of 

 the towing was done either before July or from September on, when this copepod is 

 scarce, with only five towing stations for August, at two of which it occurred. 



Anomalocera is peculiar among Gulf of Maine copepods in being seldom, if 

 ever, abundant even at the season when it is practically omnipresent, the catch 

 usually amounting to less than 50 to 60 individuals (Bigelow, 1915, p. 288). In 

 tow after tow Doctor Kendall found only one or two or " a very few." Sixty is the 

 largest number actually counted for any of the horizontal hauls in the gulf since 

 1912, and 550 the greatest frequency per square meter in any of the verticals (Massa- 

 chusetts Bay, station 20120, May 4, 1920). Drifting along in a dory on a day when 

 the water is glassy calm, Anomalocera may often be seen right in the surface film, 

 when, as Sars remarked (1903, p. 141), its movements are exceedingly rapid and 

 energetic. On such occasions I have usually noticed one here and one there, 

 seldom more than half a dozen or so together. Evidently it can never be important 

 in the economy of the Gulf of Maine, where it has not been reported from the dietary 

 of either mackerel, herring, or other plankton-eating fishes. 



On the other side of the North Atlantic this copepod must be far more plentiful, 

 for Brady (1878-1880) writes that it often occurs in immense profusion, and Sars 

 (1903) describes it as generally congregated in great shoals, when its presence is 

 betrayed by a disturbance of the surface like fine rain as it keeps leaping out of the 

 water. On such occasions it may well be of economic importance, and Norwegian 

 fishermen, who have christened it "blue bait," consider its presence a good sign of 

 the approach of the schools of summer herring; but T. Scott's (1911) failure to find it 

 in fish stomachs raises the question whether it is actually eaten to as great an extent 

 as has been supposed. 



No direct observations have been made on the breeding of Anomalocera in the 

 Gulf of Maine, but the geographic distribution of the localities where it has been 

 taken argues that local multiplication of the few that survive winter and spring — ■ 

 not immigration — is the cause of the augmentation that takes place in its numbers in 

 midsummer. The fact that there is no preponderance of locality records in the 

 eastern side of the Gulf is especially significant in this connection, because most 

 immigrants occur there chiefly, and are more or less localized around the periphery 

 of the gulf (p. 51) instead of as evenly and universally distributed as Anomalocera is. 



Of all the Copepods occurring with any regularity in the open gulf Anomalocera 

 is the most distinctively a surface form. This is especially the case during its period 

 of abundance in August. In 1913, for example, most of the records for that month 

 were from surface hauls, "only one from a haul as deep as 40 fathoms; and of course, 

 that one specimen may have been caught at or near the surface; and this may also 

 be true of the few specimens yielded by hauls from 20, 25, and 30 fathoms in the 

 Gulf of Maine" (Bigelow, 1915, p. 295). 



This tendency to keep close to the surface was well illustrated in August, 1914, 

 at the following stations, in spite of the fact that the mouth area of the surface net 

 was much less than that of the nets towed deep. 



