MANUAL OF FISH-CULTURE. 105 



The method of capture is by gill uets, pound nets, hook and line, 

 and in Avinter by spearing through the ice. The majoritj^, however, 

 are taken from gill nets operated by steam tugs. These boats are fitted 

 out with the most approved appliances of their trade and have quar- 

 ters on board for the men employed, usually a crew of 8 or 10. Some 

 of the tugs carry 5 or 6 miles of nets and catch in one lift from 1,000 

 pounds to 4 or 5 tons of trout. Fishing is done from the time the ice 

 breaks up in the spring until late in the fall or early winter, the work 

 ceasing only when the weather and ice no longer permit operations. 

 In some localities the water becomes so warm during summer as to be 

 detrimental to the nets, and consequently at such points there is a 

 lull in the work for a few weeks. Lake trout spawn on the reefs and 

 live in deep water during the remaining time, and their migratory 

 habits govern the movements of the tugs, the fishermen necessarily 

 moving from one point to another. The small gill-net boats, carrying 

 sails and handling a few hundred feet of nets, confine their operations 

 to more shallow water and fish only during the spawning season. At 

 Detour, Lake Huron; at some points in Lake Superior, and on the 

 north shore of Lake Michigan pound nets are in use, but usually these 

 nets are not used to any great extent for the capture of lake trout. 



NATURAL SPAWNING. 



Spawning commences the last of September in Lake Superior and 

 later in the lower lakes, since the water does not become sufficiently 

 cool here as early as in the headwaters. In Lakes Huron and Michi- 

 gan the height of the season is in the early part of November, and 

 spawning continues to the first of December. The spawning-grounds 

 are on the reefs of "honeycombed" rocks, 10 to 15 miles from shore, 

 and during the reproductive period vast numbers of fish visit these 

 places, spawning in a depth of from 1 to 20 fathoms. Owing to the great 

 depth of water, the shyness of the fish, and the severity of the weather 

 at this time, nothing definite has been determined as to the fish's 

 maneuvers while spawning. The supposition is that the female lies 

 over an indentation of the rocks and allows her eggs to settle into the 

 "honeycomb" cavities; fragments of the rock with the cavities filled 

 with eggs having been hauled in by fishermen when lifting their nets. 

 No doubt the general characteristics of the Salmonidce are carried out 

 by the lake trout as far as the conditions in which they exist permit. 



An instance has been known of a Mackinaw trout of 24 pounds weight 

 containing 14,943 eggs; but not over 5,000 or 6,000 eggs are commonly 

 found, and 1,000 eggs to the pound of fish may be accepted as a general 

 rule, after the trout have attained maturity, at three years of age. 



A much smaller variety, called the shoal trout, is found in Lake 

 Huron in the vicinity of Alpena, and in Lake Michigan near Charle- 

 voix and Northport, but its weight compared with its length is greater 

 than that of the true Mackinaw trout, and the markings and appearance 

 of the two also differ. The shoal trout spawns in September, about a 



