GREAT LAKES COREGONIDS 



521 



mined as much by the trout that they take along with the whitefish. In the southern 

 part of the lake the trout outnumber by far the whitefish, and as the trout here 

 frequent deeper water than in the north, such few whitefish as still occur along the 

 shores are not taken often in the gill nets. Out of most of the ports (Manistee, 

 Frankfort, North port, St. James, Traverse City) the nets find the whitefish in 20 

 to 30 fathoms when the ice leaves in April. By the middle of June the nets are, on 

 an average, 10 fathoms shallower, and they are left at this depth for the summer. 

 The gangs usually are moved in and out, according as the fish are found best at the 

 deep or shallow ends of the gangs. During the last of August and early in September 

 few whitefish are found anywhere, and it is not known whether they swim off the 

 bottom at this season or avoid the nets. When the water begins to cool they are 

 found again, and from late October until the spawning season is over they may be 

 taken still nearer the beaches. In the fall the fish move in and out from day to day. 

 Some whitefish are taken through the ice at depths of 10 to 20 fathoms. 



The data from the two types of apparatus show the same habits for the white- 

 fish. As soon as the ice leaves the fish are driven to the deepest water in which they 

 ever are taken abundantly, namely, 20 to 30 fathoms. Individuals stray into deeper 

 water occasionally during any season, and specimens have been caught in 60 fathoms 

 or even deeper. One such is recorded from off Charlevoix, Mich., in Table 81. 

 When the water begins to warm they approach the shores, and in July, in most 

 localities, they are taken most abundantly in the pounds at depths of 16 to 65 feet 

 (3 to 11 fathoms). In July and August the gill nets take them best at 10 to 20 

 fathoms. In fall they come ashore again and are taken best first by the pound nets 

 and later, when they are spawning, by the gill nets. During the winter they probably 

 remain near shore under the ice, but when the ice breaks they are driven to deeper 

 water, possibly by the heavy shore currents at this time or in quest of food. 



BREEDING HABITS 



The time of spawning varies from year to year, but almost everywhere it begins 

 sometime between November 15 and December 15. The season continues for about 

 two weeks. The fishermen believe that the water must cool before the fish will 

 spawn, and as some seasons are warmer than others, a variation in dates is to be 

 expected. All the fish that gather on the various grounds do not spawn at the same 

 time, in a given season, even in the same general area. Some of the interesting 

 variations in the time of spawning for the vicinity of Grand Traverse Bay have been 

 reported to me by John Greilick, of Traverse City, Mich., and B. Peter Anderson, 

 of Northport, Mich., and for the northern islands by James and W. J. Gallagher and 

 Dennis and Hugh Boyle, of St. James, Mich. Their observations have been con- 

 firmed by other fishermen. The spawning "season of the whitefish in Grand Traverse 

 Bay, at Mission Point, is two weeks later than at the Grand Traverse Lighthouse 

 Point. Those at Tucker Point spawn still later than the Mission Point fish. Off Hog 

 Island the whitefish may spawn in late October, while on Boulder Reef and off the 

 Fox Islands the season will be a month later. The trout schools also are known to 

 have varied spawning times in this area. 



Spawning grounds are scattered all along the shores of the lake, but the most 

 important are at the northern end of the lake on the reefs around the islands. Boulder 



