214 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Figure 98. — American pollock (Pollachius virens), Eastport, Maine. From Goode. Drawing by H. L. Todd. 



three (21 or 22 rays) and is separated by a con- 

 siderable space from the third dorsal fin (19 or 20 

 rays) which is more rhomboid in outline. The 

 second anal fin (20 or 21 rays) corresponds in 

 shape and size to the third dorsal, under which it 

 stands, but the first anal (24 to 28 rays) is consid- 

 erably longer than the second dorsal though similar 

 to the latter in shape. The ventral fins are a little 

 in front of the pectorals, and are only about half 

 as long as the latter. The pectorals are set high 

 on the sides, and are longer than the first dorsal, 

 but shorter than the second dorsal; they have 

 rounded lower corners and bluntly pointed tips. 

 The caudal fin is noticeably forked, with angular 

 corners, unless it is spread to its widest when its 

 margin becomes nearly straight. 



Color. — Pollock are always of a greenish hue, 

 usually deep rich olive green or brownish green 

 above, paling to yellowish or to smoky gray on 

 the sides below the lateral line, and to silvery gray 

 on the belly. The lateral line is white or very 

 pale gray, contrasting strongly with the dark sides. 

 The dorsal, caudal, pectoral, and anal fins are 

 olive, the latter pale at the base. The ventral 

 fins are white with a reddish tinge. Young fish 

 are darker than large ones, and many of them are 

 more tinged with yellow on their sides. 



Size. — Pollock reach a maximum length of about 

 3% feet and a weight of about 35 pounds. But 

 fish of this size are exceptional, few growing larger 

 than 40 inches or 30 pounds, with about 2 to 3 

 feet and 4 to 15 pounds as the average for adults. 

 The proportion of length to weight was as follows 

 among fat fish measured by Welsh off Boon Island 

 on April 22 to 25, 1913: 



Large pollock, however, of a given length vary 

 widely in weight; for example, we have found 40- 

 inch fish to weigh from 25 to 35 pounds; 35-inch 

 fish, from 14 pounds to 21 pounds. 



Habits. — The pollock is an active fish, living at 

 any level between bottom and surface according 

 to the food supply and on the season, often school- 

 ing, and sometimes gathering in bodies so large 

 that it is on record that a purse seiner once took 

 60,000 fish from one school at a single set. In our 

 Gulf their depth range is from the surface down to 

 100 fathoms at least, 1 while they may descend 

 somewhat deeper in the deepest troughs. And it 

 is the local presence or absence of prey that gov- 

 erns the movements of the larger pollock. 



Pollock feed chiefly on small fish, and on pelagic 

 crustaceans; among the latter most often on the 

 large pelagic shrimp-like euphausiids. It is com- 

 monplace that pollock destroy great quantities of 

 small herring, launce, young cod, young haddock, 

 young hake, silver hake, and other small fish in 

 the Gulf of Maine just as they do on the other side 

 of the Atlantic. Pollock chasing schools of herring 

 are a familiar sight; 2 pollock of 1 to \){ pounds 

 commonly run up estuaries in pursuit of smelt in 

 autumn; and newly hatched haddock or other 



' We have seen them trawled as deep as this on the northern slopes of 

 Georges Bank. 



' Sars (Kept. U. S. Comm. Fish., (1877) 1879, p. 619-620) has given a graphic 

 account of pollock rounding up schools of launce and of young cod in Nor- 

 wegian waters. 



