120 REPORT OF COMMISSIONER OF PISH AND FISHERIES. 

 COMMERCIAL AND FOOD VALUE, ETC. 



The wliitelishes are by far the most important groui) of fresh-water 

 fishes of North America, probably of the world. The common white- 

 fish is the best of the tribe, but some of the others nearly equal.it in 

 merit, and all are more or less esteemed as food. Among the fishes of 

 the Great Lakes the common whitefish ranks next in value to the lake 

 herring, lake trout, and wall-eyed pike. In 1893 the catch in the United 

 States was over 8,000,000 pounds, having a value of over 1330,000. If 

 to this is added the yield of other species (namely, about 36,000,000 

 pounds of lake herring, valued at $530,000, and upward of 3,000,000 

 pounds of other whitefish, valued at $85,000), the aggregate is over 

 47,000,000 pounds, having a value of $951,000. The market value of 

 the whitefishes taken in 1893 in the British Provinces was reported as 

 $1,535,000, a sum representing about 30,000,000 pounds. 



The common whitefish reaches a larger size than any other species 

 of whitefish in the United States. Examples weighing over 20 pounds 

 have been taken, but the average weight is under 4 pounds. 



Whitefish fishing is done chiefly with gill nets set at or near the bot- 

 tom in comparatively deep water, although considerable quantities of 

 whitefish are also taken in pound nets, trap nets, and seines. 



SPAWNING. 



The spawning season of the whitefish begins the latter part of Octo- 

 ber and continues into December. At that season there is a general 

 movement of the fish to shoal parts of the lakes, similar to the migra- 

 tion of anadromous fishes from the ocean to the rivers; some of the 

 the foreign whitefishes are typical anadromous species. After spawning, 

 the fish return at once to the deeper water. 



The spawning habits of whitefish confined in pens have been observed. 

 The fish rise to the surface, occasionally in pairs, sometimes, but rarely, 

 in trios of one female and two males, the female emitting a quantity of 

 spawn at each rise. The males, always the smaller fish, persistently 

 follow the female and discharge milt at the same time the- eggs are 

 emitted. 



Whitefish reach maturity in the third or fourth year. A full-grown 

 specimen deposits from 10,000 to 75,000 eggs, depending on the fish's 

 size. A rule for determining the approximate spawning capacity is to 

 allow about 10,000 eggs for each i)ound of the fish's weight. The eggs 

 when fully swollen are an eighth of an inch in diameter, and 36,000 

 make a fiuid quart. They swell somewhat after impregnation. 



DESTRUCTION OF WHITEFISH SPAWN IN NATURE. 



In nature the eggs of the whitetish are subjected to the attacks of 

 many enemies for nearly five months. The mud-puppy {Necturus mac- 

 ulaUis), commonly known as "lizard" or "water-dog" by the people 

 along the lakes, is especially destructive. During the month of Janu- 



