PLANKTON OF THE GULF OF MAINE 103 



shrimp (Meganyctiphanes and Thysanoessa) , which so often appear on the surface 

 there (S. I. Smith, 1879). Richard Rathbun (1889) reports some of the mackerel 

 that he examined from the southern fishery (off the coasts of Virginia and Maryland 

 in latitudes 37° 4S' N. and 38° 01' N.; longitudes 74° 13' and 74° 21' W.) in 1887, 

 as full of copepods and others of euphausiids. Dr. W. C. Kendall found the mackerel 

 on the northern part of Georges Bank feeding on Calanus (probably also Pseudoca- 

 lanus) and on small brown copepods (probably Temora), as well as on other plank- 

 tonic animals (Bigelow and Welsh, 1925, p. 201) ; and many more instances might be 

 mentioned where copepods, euphausiids, or both, have been reported as mackerel food 

 in American waters as well as in European. The larger copepods also enter to some 

 extent into the dietary of the American pollock (Pollachius virens) in the Gulf of 

 Maine — witness Willey's (1921) record of a fish taken near Campobello Island with 

 many Euchxta norvegica in its stomach and some Calanus JinmarcMcus and C. 

 hyperboreus. 



Euphausiid shrimps offer as important a food supply for this large and active 

 gadoid as do small fish. Thus, Moore (1898) describes pollock at Eastport as feed- 

 ing chiefly on them and following them in their appearances and disappearances. 

 Wflley (1921) also found pollock feeding on euphausiids at Campobello. Welsh saw 

 great numbers of pollock schooling in pursuit of shrimps and greedily feeding on 

 them in the neighborhood of the Isles of Shoals in spring, as I have described elsewhere 

 (Bigelow and Welsh, 1925, p. 401). 



In the North Sea region medium-sized specimens of this gadoid (there called 

 the "coalfish" or "green cod") eat considerable amounts of small pelagic Crustacea, 

 such as Calanus, Temora, Centropages, Pseudocalanus, cirriped larva?, ostracods 

 (Evadne), as well as euphausiids, in addition to the small fish and to the bottom- 

 dwelling worms and Crustacea that form their staple food. 



It is probable that when euphausiids descend toward the bottom in the Gulf of 

 Maine they become food for the hakes (genus Urophycis), which, in the main, are 

 shrimp eaters (Bigelow and Welsh, 1925, p. 450), and which are known to gorge on 

 euphausiids along the outer part of the continental shelf (Hansen, 1915, p. 94). So, 

 too, the deep-water fish Macrourus (Bigelow and Welsh, 1925, p. 470) ; and even as 

 typical a bottom and fish feeder as the cod is known to adopt a pelagic life and to 

 feed on euphausiids off the north and east coasts of Iceland (Paulsen, 1909, p. 39; 

 Schmidt, 1904). The common skate {Raja erinacea) also feeds on copepods on 

 occasion (Linton, 1901, p. 279), though this is quite exceptional for it. 



In North European waters the hyperiid amphipods are a major food for herring 

 (Brook and Calderwood, 1886), but although the genus Euthemisto is widespread 

 and at times locally abundant in the Gulf of Maine, I have found no record of 

 herring feeding on it there, and have recognized none in the stomachs of the Gulf of 

 Maine herring I have opened. Probably this is due to the mutual geographic distri- 

 bution of the two animals, Euthemisto being most plentiful offshore and herring 

 along the coast. These amphipods may be expected to form an important item 

 in the diet of herring on Georges Bank. This is certainly true of the mackerel 

 there, for Dr. W. C. Kendall found the latter feeding on Euthemisto on the northern 

 part of the Bank in August, 1896 (Bigelow and Welsh, 1925, p. 201) . Mackerel taken 



