FISHES OF THE GULF OF MAINE 209 



75. Chub mackerel (Pneumatophorus colias Gmelin) m 

 Hardhead; Bullseye; Spanish mackerel 



Jordan and Evermann (Scomber colias), 1896-1900, p. 866. 



Description. — So closely does the " hardhead " (by which name it is commonly 

 known to fishermen) resemble the common mackerel that we need mention only 

 the points of difference. Most important of these, anatomically, is the fact that 

 P. colias has a well-developed swim bladder connected with the esophagus, which 

 the mackerel lacks; but it is not necessary to open the fish to identify it for there 

 is a characteristic color difference between the two, mackerel being silvery-sided 

 below the median fine, whereas the lower sides of the hardhead — otherwise colored 

 like the mackerel — are mottled with small dusky blotches. Less obvious differ- 

 ences are that the dorsal fins are closer together in the hardhead and that there 

 are only 9 to 10 spines in its first dorsal fin instead of 11 or more, as in the mackerel. 



Size. — This is a smaller fish than its better-known relative, growing to a length 

 of about 8 to 14 inches only. 



General range. — Temperate Atlantic Ocean, north to the Gulf of St. Lawrence," 

 and to England. It is represented in the Pacific by a close ally — Pneumatophorus 



japomcus. 



Fig. 94.— Chub mackerel (Pneumalophorus colias) 



Occurrence in the Gulf of Maine. — Goode, et al. (1884), long ago summarized 

 the peculiar history of the chub mackerel in our waters, which briefly is as follows: 



It was tremendously abundant during the last of the eighteenth century and 

 early years of the nineteenth century and down to 1820-1830, but it practically 

 disappeared from the United States coast some time between 1S40 and 1850. It is 

 interesting to note, as Captain Atwood pointed out, that destructive methods of 

 fishing had nothing to do with the case, since its disappearance antedated the in- 

 troduction of traps, pounds, or purse seines, and similarly antedated the reappear- 

 ance of the bluefish (p. 239), and hence can not be blamed on these sea pirates. 

 So completely, indeed, did the hardheads vanish that for 10 years prior to 1879 



M This genus is separated from Scomber by the possession of a well-developed swim bladder which the true mackerel lacks 

 (see Starks, Science, new series, Vol. LIV, 1921, p. 223). 



" Schmitt (Monographic de l'isle de Anticosti, 1904, p. 285, Paris) credits it with "apparitions irregulieres" at Anticosti. 

 " For the distinctions between the two see Starks (Copeia, No. 103, February, 1922, pp. 9-11). 



