446 



their death is obscure, it being hardly possible that the explanation offered as to 

 some of the smaller lakes of New York State — the use of explosives for wholesale 

 killing of food-fish — is the true one. 



The shad {G. sapidissima) is undoubtedly one of the most important of Am 

 erican food fishes. It used to be abundant in the Lower Ottawa, but the pollution 

 of the river^ by sawdust etc., appears to have rendered its former spawning grounds- 

 unavailable. Its spawning habits resemble those of the Alewife; the eggs are spun 

 out by the female on to a sandy bar while in rapid motion, and the male scatters 

 the milt at the same time, both sinking slowly to the bottom. Three to eight days 

 suflfice for hatching, after which the young escape and are able to swim freely. 

 A ripe shad contains from twenty to forty thousand eggs. The males are smaller 

 (l|-6 lb.) than the females (3|^-8) and are earlier mature. The same apparent 

 local instinct is said to be exhibited by the shad as by the salmon ; the young 

 hatched in any particular stream returning to it after an interval of two to three 

 years when adult. It is possible that this is to be interpreted by their not going 

 far from the mouths of the rivers m which they have been bred 



Allied to the shad is a fish of similar form recently introduced into Lake 

 Ontario and Erie, but of no value economically. It is known as the Gizzard- 

 shad (Dorosoma cepedianuTn) on account of its muscular stomach and is further 

 distinguished by the last ray of the dorsal being produced into a long thread. It 

 has occasionally been found dead at the surface in considerable numbers. 



By far the most important family of the fresh-water Teleosts, as regards 

 economical value and the number of species, is undoubtedly that of the Salmonid^ 

 Like the foregoing, many of the members are anadromous, living a part of their 

 life in the sea but ascending rivers to spawn. Other forms which are confined to 

 large bodies of fresh water often congregate about the mouths of the rivers fall- 

 ing into them or ascend these for the same purpose. The Capelin (Mallotus 

 vUlosus) and Smelt (Osmerus eperlanus) are exclusively marine forms; the Salmon 

 and Trout are found in both salt and fresh water, while the Whitefish, Grayling 

 and Lake Trout are confined to inland waters. 



In all of the forms that concern us here, the intestine is furnished with 

 numerous pyloric coeca, which serve to increase its surface. Unlike the shad the 

 abdomen is rounded, and there is present an adipose fin> The Whitefish 

 (Goregonus) are distinguished by an entire absence of teeth, and by the large 

 size of the scales. Of the toothed genera, the Grayling (Thymallus) is at once char- 

 acterized by its long and high dorsal fin, while the Salmon (Salmo) and Brook 

 and Lake Trout (Salvelinus) agree in having teeth on the jaws and tongue, but 

 differ in that the vomer in the latter genus is destitute of teeth. 



The genus Goregonus is not confined to North America but is also found in 

 large inland waters — such for example as the Swiss Lakes — in Europe and Asia. 

 The species are somewhat diflicult to distinguish, innumerable local varieties 

 being recognized by fishermen, which probably do not deserve to rank as distinct 

 species. The body is compressed in all and the air-bladder very large, the 

 pyloric coeca very numerous, and the eggs numerous and of small size. 



Six species occur within the Province, which may be arranged in two groups 

 according as the lower jaw is included within or projects beyond the upper. To the 

 former belongs the common Whitefish {C. clupeiformis), and with it G. quadrila- 

 teralis, G. lahradoricus and C. hoyi, while to the latter belong the Lake Herring 

 (C artedi) and the Tullibee of Manitoba, (C tullihee). 



