SPAWNING GROUNDS OF THE LAKE TROUT. 489 



They spawn late in October, coming up to the rocky shoals and reefs in from seventy to ninety 

 feet depth of water. They are said to spawn close to the projections and edges of cavernous rocks, 

 the eggs settling into the depressions, where they doubtless remain until hatched. The young fish 

 make their entry into the world in late winter or early spring, though in a hatching house, with 

 water at au average temperature of 47 Fahrenheit, they have been known to hatch the last week 

 in January. 



Milner remarks: "The universal testimony is that the spawn is found running from the 

 females in the hitter part of the month of October, the fish coming to the spawning grounds a 

 week or more earlier. At Detour, at the head of Lake Huron, on the 16th of October, I saw a large 

 lift of Trout brought in from the spawning grounds; the ova were large and separated, but were 

 still entirely retained in the folds of the ovaries, and the fishermen said that they had not found 

 them running from this fish as yet. 



"The localities selected by the Trout for their spawning ground are usually rock bottoms in 

 from fifteen fathoms to seven feet of depth. The Trout are said to settle close to the projections 

 and edges of the honey-combed cavities of the rock, and that frequently, when a loose fragment 

 of the rock is drawn up by the nets, the cells are found to contain numbers of the eggs." 



Mr. Milner counted the eggs of a Mackinaw Trout, of twenty-four pounds' weight, and found 

 that there were 14,943. The average weight of these fish as taken in the gill-nets was about five 

 pounds, though fish of fifteen pounds are frequently seen. Mr. Milner obtained authentic accounts 

 of one, taken at Mackinaw in 1870, which weighed eighty pounds. The species is the largest, 

 except the sturgeon, occurring in the Great Lakes. 



"The knowledge of the time at which the young fish make their appearance is limited to the 

 experience of the few fish-culturists in the country who have hatched the eggs. In water of an 

 average temperature of 47, they are found to hatch about the last week of January. At the 

 lower temperatures of the water, in a state of nature, their development would be retarded for 

 several weeks. 



" Of the habits of the young Trout I am entirely destitute of information. I have seen one of 

 eight inches in length, and learn of rare instances in which the fishermen have seen small ones." 



The principal spawning grounds of the Lake Trout are the following: 



I. The north shore of Lake Superior, from Duluth northward to the vicinity of Isle Royale, 

 comprising the whole lake coast of Minnesota, and in all the small bays of the region. 



II. In the vicinity of the Apostle Islands, hi the western part of Lake Superior, especially 

 about Gull Island. 



III. Very extensive spawning grounds in the vicinity of Huron Bay, Michigan, particularly 

 near L'Ause and Bete-Grise Bay, and on a reef about four miles from Porte Gentre. 



IV. Very extensive spawning grounds in the southeastern part of Lake Superior, at Big 

 Presqne Isle, Laughing Fish Island, Sharp Point, and Sauk's Head, Michigan. 



V. On the west shore of Lake Michigan, from Racine northward, particularly upon a reef about 

 forty miles off Milwaukee, and on a smaller reef about six miles from the same town. On this 

 ground, according to Milner, a large type of Trout has been taken for many years, also on certain 

 shoals in the vicinity of Green Island in Green Bay. 



VI. On the eastern shore of Lake Michigan, from Saint Josephs northward. 



VII. In the vicinity of Detour, at the head of Lake Huron. At this point, according to Milner 

 (.also according to Kumlien, along the islands oft' Thunder Bay and Harnsville), the spawning 

 ground was so close to the shore that the tips of the floats of the nets set upon it were visible 

 above water. 



