528 



BULLETIN OF THE BUREAU OF FISHERIES 



fish were beginning to spawn. Off Barrie Island, Mr. Merrylees, of Gore Bay, told 

 me, they were beginning to spawn on November 10, 1917. Some males of the catches 

 examined here in 1919 as early as September 27 showed pearl organs well developed. 

 At Kagawong, on November 10, 1917, the fish taken were not yet ripe. In Lake 

 Huron, at Alpena, Mich., the spawning season was just beginning on November 16, 

 1917, according to the spawn takers. The males, they said, had been on the grounds 

 earlier. Furthermore, the time of spawning varies from year to year. What factors 

 influence the ripening of the fish is not known. Some fishermen claim that the 

 moon has something to do with it, but exactly what influence the moon exerts is not 

 clear. It need hardly be said that a closed season for the purpose of protecting the 

 spawning fish, the dates of which are fixed once for all and which holds for every 

 port on the lake, can not accomplish its purpose effectively. 



The bottom preferred by the spawning fish is the limestone formation known as 

 honeycomb rock and gravel. Bower (1897) mentions the honeycomb and adds 

 "sometimes on a solidly paved cobblestone bottom, the latter sometimes interspersed 

 with bowlders." Rathbun and Wakeham (1897) say, for Lake Huron, "spawning 

 grounds are found at intervals on rocky or sandy bottom." Milner (1874a) says of 

 the whitefish in the Great Lakes, "the bottoms on the spawning grounds vary in 

 character in different localities, rock, sand, clay, and mud being used indifferently 

 for the spawning beds." Leathers (1911) tells of their spawning on the broad sand 

 flats in Huron County, Mich. 



The depth at which the fish spawn varies. Some fishermen say the fish will 

 spawn in as little as 4 feet of water, while others insist that the fish run into this 

 shallow water previous to the spawning season (as do the trout) and that they then 

 repair to 6 to 8 fathoms to spawn. One of the best spawning grounds in the lake 

 lies off Alpena, 6 miles NNE. of Thunder Bay Island, in 8 fathoms of water. 



ABUNDANCE 



The whitefish in Lake Huron is now much less abundant than formerly. It 

 occurs commonly in relatively few localities. In the vicinity of Alpena and Saginaw 

 Bay on the American side and along certain sections of the North Channel and of the 

 north and east shores of Georgian Bay on the Canadian side it is still the object of 

 special fisheries, but here, as elsewhere, the increased importance of other kinds of 

 fish that are taken incidentally has sustained the fishery in late years. 



FOOD 



Doctor Hubbs finds, from an examination of the stomach contents of 160 speci- 

 mens collected off Alpena, Mich., from September 17 to November 2, 1917, and 1919, 

 that Pontoporeia constitued the bulk of the food, supplemented in almost every case 

 by small bivalved and univalved mollusks (Sphserium, Amnicola, etc.). Sand, 

 gravel, cinders, wood fragments, seeds, etc., were present as accidental inclusions in 

 most stomachs, and Chironomidae larvae also were of frequent occurrence. Articles 

 occasionally ingested include bryozoan statoblasts, adult land insects, Trichoptera 

 larvae, Corixidse, and fish (Cottus jranklinii). One specimen collected on October 

 22, 1917, off East Tawas, Mich., had eaten chiefly Sphserium and small gastro- 

 pods, with some sand and cinders included. Fifteen individuals collected on October 



