Fishes of the Western North Atlantic 119 



been described repeatedly as "common."^" We have hooked or sighted on an average 

 about one per three or four days on the cod fishing grounds, generally in the western side 

 of the Gulf of Maine and on Nantucket Shoals during the summers of 1924 to 1930.^° 

 However, the fact that such large numbers have been caught in the past within brief periods 

 (see above) is sufficient evidence that their numbers vary widely from year to year, or over 

 a period of years, at least locally. 



To the westward nasus is described (we have no first-hand information) as compara- 

 tively common in the vicinity of Woods Hole (more so in autumn) and it has been re- 

 ported on several occasions from Rhode Island coastal waters. However, it appears only 

 as a stray along Long Island, New York (one record), or along the New Jersey coast; the 

 only evidence of its presence farther south is one somewhat doubtful report of it off 

 Charleston, South Carolina. From this it appears that the isothermal belt of about 6s° F. 

 limits its normal range to the southward. 



It seems equally certain that its on-and-off-shore range is similarly narrow, for we 

 find no record of it (nor report of it by fishermen), from the offshore fishing banks abreast 

 of the Gulf of Maine (Georges and Browns Banks) ; only one is reported from the Nova 

 Scotian slope (see Study Material, p. 112), and two from the Grand Banks. On the other 

 hand, few venture close enough to land to be picked up in the pound nets. There is, how- 

 ever, record of a Mackerel Shark, probably this species, which was entangled in the eel 

 grass (Zoslera) in Barnstable Harbor, Massachusetts, many years ago." In the western 

 Atlantic all published records of it, and those that we have observed, have been for the 

 warm half of the year, but its presence in the Gulf of Maine in winter is proved by our 

 receipt of a photograph of an embryo, certainly of this species, from a female caught off 

 Portland, Maine, in January of 1927. Similarly, it is taken in winter as well as in summer 

 off northern Europe, but less commonly. This, together with the absence of any evidence 

 of migration southward along the middle Atlantic coast of the United States, suggests 

 that in winter they simply descend into deeper water to avoid low surface temperatures, 

 apparently feeding little then, otherwise more of them would be picked up by the winter 

 fishery for hake. 



Synonyms and References: 



Porbeagle, Borlase, Nat. Hist. Cornwall, 1758: 265, pi. 26, fig. 4 (Cornwall) ; Pennant, Brit. Zool., 3, 1 769: 



92 (descr., Cornwall) ; also later eds. 

 Squdus glaucus Gunnerus, K. norske Vidensk.-Selsk. Skr. Trondh., 1768: I, pi. I (descr., embryo, Nor- 



19. Actually, no sharks, other than the Spiny Dogfish, are ever common off the northeastern coast of the United 

 States or Canada, in the sense in which that term can be applied to such fish as the cod, mackerel, etc., but only 

 as relative to other sharks of corresponding sizes. 



20. Cod-tagging cruises of the U.S. Bureau of Fisheries. 

 »i. Goode, Fish. Fish. Industr. U.S., 1884: 670, footnote. 



