4-62 Memoir Sears Foundation for Marine Research 



gave birth to young in July on capture off Gloucester, Massachusetts.*" Young are 

 produced throughout the year in the Mediterranean, during autumn in the Black Sea, 

 while in more northern European waters there is wide regional variation, i.e., late summer 

 through autumn into winter in the English Channel, and late April through the summer 

 in the North Sea and in Scandinavian waters.'^ It is probable that pairing takes place shortly 

 after the young are born, but no definite information is available. 



Food. The Spiny Dog is as voracious as any fish of its size, and its wanderings on 

 the coast are no doubt chiefly in pursuit of food. Its recorded diet in the western Atlantic 

 includes capelin, herring, menhaden {Brevoortia), mackerel, scup {Stenotomus), silver 

 hake (Merluccius), cod, haddock, pollock, blennies and croakers (Micropogon). No 

 doubt it preys on practically any species of fish smaller than itself. Even when newly 

 born they have been seen attacking herring much larger than themselves, as adults do cod 

 and haddock. Fishermen have often described them as harrying schools of mackerel and 

 herring even in the seines, as well as destroying large numbers of cod and haddock in 

 addition to driving them away, and they often bite these and other ground fish from the 

 hooks of long lines. They also prey on squid and to some extent on worms, shrimps, prawns, 

 crabs and amphipods. They occasionally feed on gastropods and jellyfish (Aurelia), and 

 even red, brown and green algae have been found in their stomachs.^*" When they first 

 arrive near Woods Hole in spring they are often full of ctenophores. Probably they feed 

 very little during the winter, for fishermen describe them as thin when they reappear on 

 the coast in spring. 



Relation to Man. In northern Europe the Spiny Dogfish is of considerable commer- 

 cial value as a food fish; in 193 1, for example, it fetched the fishermen about 5 cents per 

 pound in the markets of Germany, and the landings for that year came to perhaps 14,000,- 

 000 pounds, as estimated from the total catch of sharks of all sorts." Similarly, the British 

 landings for 1923 were 9,597,900 pounds, worth £49,980.'* However, on the American 

 coast the Spiny Dogfish has never been in demand for the table, although many years ago 

 they were of some value for oil. During more recent periods when they were in great 

 abundance, various efforts were made in America to utilize Dogfish on a large scale both 

 as fertilizer and as a source of oiP^ to combine with cod liver oil (it compares favorably 

 with the cod for Vitamin A, although its Vitamin D content is much lower) ; it has also been 

 canned for human consumption. And fresh, this is a better food fish than is generally appre- 

 ciated. On the coasts of the eastern United States and Canada, however, these attempts 

 have been short-lived. Of late years Spiny Dogfish have been so little considered that there 

 is no way of knowing how great a proportion of the total landings of sharks of all kinds 



35. Mclntire, in Rep. Comm. Fish. Game Mass. (1905), 1906: 108. 



36. For details and authorities, see Ford (J. Mar. biol. Ass. U. K., N. S. /;, 1921 : 481, 482). 



36a. For a recent list of stomach contents, see Templeman (Res. Bull. Dep. Nat. Resources Newfoundland, 1944: 49). 



37. For details, see Lijbbert and Ehrenbaum (Handb. Seefisch. Nordeurop., 2, 1936: 285). 



38. Jenkins, Fish. Brit. Isles, 1925: 321. 



39. Liver oil in the amount of 176,200 gallons was produced from this species in Canada in .936 (Hampton, 

 Newfoundl. Fish. Res. Inst. Serv. Bull., 5, 1938: 5). 



