UTILIZATION OF DOGFISH 129 



in composition most like the salmon is best adapted for canning and is considered as 

 good as the medium grades of salmon. A packer in Petit de Grat, Cape Breton, in 1904 

 sent me a dozen cans of dogfish he had packed. I passed them round to my friends, 

 who prepared the contents in different ways (fried, scalloped, creamed, etc.). In these 

 forms the canned article was highly praised for flavour and palatability. Samples 

 were also sent to several hotels where the fish was served to the guests as ' Japanese 

 halibut,' and was pronounced most acceptable. An establishment at Halifax has been 

 canning large quantities and putting them on the market labelled ' Ocean whitefish.' 

 A firm at Charlottetown, Prince Edward Island, has been successful in selling the 

 canned article as ' sea bass.' " 



The flesh of the skate has long been relished in England and on the continent; 

 during the last two years it has been for sale in fish stores in the Eastern United 

 States. Shark flesh has been sold for the last two years in New York. 



3. THE UTILIZATION OF SELACHIANS FOR OTHER PURPOSES THAN 



FOR FOOD. 



(a) TO OBTAIN OIL. 



Oil can be obtained from the liver of nearly all selachians. The "Dogfish oil " 

 of the American market is said by Jordan and E nermann (1896) to be obtained from 

 Squalus acanthias. '' Shark oil " and " Ray oil " are also on the market. These oils 

 are used in the currying of leather. 



(h) TO MAKE GLUE. 



Glue has been made from the smooth dogfish, Mustelus canis, of American 

 waters. This form does not occur commonly as far north as the Canadian coast. 

 Our own horned dogfish, Squalus acanthias, is said by G. F. White (1917) not to be 

 suitable for the production of glue. " Attempts to produce glue from the grayfish 

 (Squalus acanthias) have not been successful on account of the large amount of oil 

 and water in the fish, the difficulties attended with the extraction of the oil, and the 

 presence of dark pigments in the skin which discolour the extracts. It is also pro- 

 bable that the skeleton contains only a small amount (if any) of collagen or glue- 

 forming substance. The flesh of the smooth dogfish (Mustelus canis) contains 

 gelatin-forming material and presents possibilities as a source of glue." (^i) " That 

 the manufacture of fish glue alone is not very profitable may be seen from th« fact 

 that glue manufacturers do not rely on this one product as a source of profit." (^-) 



(c) AS A FERTILIZER. 



The flesh of selachians, like that of other fishes, for example the menhaden, is 

 rich in fertilizing constituents, containing from Y to 8 per cent of nitrogen and 6 to 

 8 per cent of phosphoric acid. The availability of this nitrogen is much reduced if oil 

 is present. Hence in the ease of selachians containing a considerable quantity of 

 oil, as for example our horned dogfish, the oil ought to be extracted. 



(d) OTHER USES. 



The skin of dogfish is used for the preparation of shagreen, a kind of rough 

 leather. It was also used for polishing, its place being now, however, largely taken 

 by the various kinds of sand and emery papers. 



The eggs of the dogfish have been found to be a good substitute for hen eggs in 

 the process of tanning. 



lie. F. White, 1917, p. 12. 

 12 C. F. Wliite, 1917. p. 14. 



79550—9 



