22 U. S. BUREAU OF FISHERIES. 



SPAWNING HABITS. 



Spawning commences the last of September in Lake Superior and 

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

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

 gan the height of the season is from November 10 to 20, and spawn- 

 ing continues to the 1st 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 maneuvers 

 of the fish 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, since fragments of the rock with the cavities 

 filled with eggs have been hauled in by fishermen when lifting their 

 nets. No doubt the general characteristics of the Salmonidse are car- 

 i-ied out by the lake trout so far as is permitted by the conditions in 

 which they exist. 



Observer of the spawning habits of the lake trout in Lake George, 

 N. Y., have the following to say on the subject : 



It is the habit of the lake trout to migrate to shallow water for the spawning 

 function, the time varying anywhere from October 25 to November 1, in accord- 

 ance with the water temperature. During the spawning period fish will be 

 found upon almost every rocky shoal, at the end of an island, or along the 

 main shore line, in from 1 to 4 feet of water, though they sometimes spawn 

 at a much greater depth. Ordinarily spawning occurs in places where there are 

 small bowlders from 1 to .3 feet or more in diameter. Between such bowlders it 

 is possible to see the trout lying side by side in pairs, each heading in an oppo- 

 site direction, as if to guard against intrusion from all points. 



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 after the trout have attained maturity, at 3 

 years of age, 1,000 eggs to the pound of fish may be accepted as a 

 general rule. 



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. Its weight compared with its length is greater 

 than that of the true Mackinaw trout. The markings and appearance 

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

 a month earlier than the Mackinaw trout. Its spawning grounds are 

 the cobble, bowlder, or gravel bottoms, in from 2 to 8 feet of water. 



ARTIFICIAL PROPAGATION. 



COIiECTION AND INCUBATION OF EGGS. 



The present methods of fishing for lake trout include gill nets, 

 seines, and pound nets, but most of the eggs taken for artificial propa- 

 gation are obtained from the gill-net fishermen. The gill nets are 

 operated from steam vessels equipped with the most approved appli- 

 ances for their trade and with living quarters for a crew of 8 to 10 

 men. 



During the egg-collecting period spawn takers are employed to 

 accompany the fishing boats for the purpose of taking ripe eggs 

 from the fish secured. Where a boat is operating a long string of 



