538 



BULLETIN OF THE BUREAU OF FISHERIES 



of most ports on the lake except off the Canadian shore, and gill nets have been 

 employed frequently to take them. The season ranges usually from October 1 into 

 December, depending on the locality and the weather. Out of Dunkirk and Barce- 

 lona nets were set for whitefish into the month of January. 



The data collected from the fishermen on the lake indicate that the whitefish 

 are found by gill nets in early spring in the deeper waters, especially in the eastern 

 half of the lake. In May the schools move onto the shoals but retreat again into 

 deeper water in early June. In the deep water at the eastern end of the lake they 

 have been found in commercial quantities during July. Thereafter, until the water 

 cools in the fall, usually none are taken by any apparatus; but in October the gill 

 nets get them again in the deeper waters, and later they move shallower and are 

 caught in the pounds and traps. Later still they repair again to deeper water. 



There is a widespread belief among American fishermen that there are only a 

 few schools (or perhaps one) of whitefish in the lake and that these fish summer in 

 the deep water of the east and migrate in the fall to spawn on the reefs to the west. 

 Such a view places too much emphasis on the observation by the fish of the inter- 

 national boundary line and does not take into consideration at all what happens on 

 the Canadian shore, where there have also been extensive whitefish fisheries. It is 

 rather likely that there are several localized schools, none of which undertake exten- 

 sive coastwise migrations. An intensive study of the fish of the various localities 

 should throw light on this subject; or, better, if marking were feasible, actual migra- 

 tions could be traced. 



BREEDING HABITS 



The whitefish spawn generally from about November 20 into December. The 

 season, of course, varies from year to year. On November 30, 1920, at Sandusky 

 and Toledo, Ohio, many of the fish had not yet begun to spawn, and at Merlin and 

 Ridgetown, Ontario, spawning had not begun on November 24, 1924. 



The largest spawning grounds of the lake are located around the Bass Islands and 

 Pelee Island, on the limestone reefs in their vicinity, and off Port Maitland. Small 

 reefs, some of which are known to be frequented by whitefish, are scattered along 

 the shores of the lake. The bottom is largely honeycomb limestone rock or gravel, 

 and the water is usually less than 30 feet deep. The western spawning grounds have 

 been virtually deserted since 1920, which was the last good year, on account of the 

 pollution by the Detroit River water, the fishermen believe. 



The minimum size of spawning fish is not known exactly, but at Merlin, on 

 November 24, 1924, spawning males were seen as small as 134 and lj^ pounds in the 

 round. Many of the fishermen on the north shore inform me that males of this size 

 commonly spawn, but that they do not recall seeing mature females so small. 



Little is known of the spawning behavior of the species except that Charles 

 Dircks, of Put in Bay, Ohio, says the males clean portions on the rocks 2 to 10 feet 

 square and that he has seen the male accompanying the female while spawning on 

 these cleaned areas. 



ABUNDANCE 



Early records show more whitefish taken on the western flats (where there 

 are now no whitefish at all) than are taken in all Lake Erie. In the last five years 



