534 



BULLETIN OF THE BUREAU OF FISHERIES 



The color in life has not been recorded carefully, but it is paler than that of the 

 Michigan form. Most of the preserved specimens have notably less pigment than 

 those from the northern waters of Lake Michigan, though it is distributed over the 

 same areas. They lack the dusky hue of the back, for the most part. One speci- 

 men, however, taken off tbe Blackwater River (a muskeg stream), is as dark colored 

 as any specimen collected anywhere in the Great Lakes. 



PEARL ORGANS 



No fish were collected by me during the spawning season, but the fishermen all 

 agree that the spawning fish develop pearls. These probably are more or less similar 

 to those exhibited by breeding fish in the other lakes. 



VARIATIONS 



Racial variations. — Specimens have not been obtained in sufficient numbers to 

 study local variation, and from the material at hand, which originated from various 

 sectors of the lake (see fig. 2), there are no indications (except for the muskeg color of 

 the specimen referred to in a previous paragraph) that local races, if they do exist, 

 are characterized by conspicuous external features. 



Size variations. — In Table 91 the five largest and the five smallest fish of my collec- 

 tion are compared extensively in certain systematic characters. The chief differences 

 between the two size groups appear to be the usual ones, namely, a relatively larger 

 head and eye in the smaller fish. Possibly a study of more specimens would reveal 

 other changes with growth. 



METHODS OF CAPTURE 



Gill nets of 43^-inch mesh and pound nets are the only apparatus employed in 

 the whitefish fisheries on Lake Nipigon. The gill netting is usually spun of sea- 

 island cotton on account of the large quantities of suckers and other rough fish that 

 are taken. The latter are very destructive to the more expensive linen netting 

 generally used in the Great Lakes. 



GEOGRAPHICAL DISTRIBUTION 



While the data given in Table 90 and platted on the lake chart in Figure 2 for 

 the specimens I have collected do not show a wide distribution of the whitefish in 

 the lake, the species actually may be found (according to the fishermen) in com- 

 mercial quantities almost everywhere in depths of less than about 35 fathoms. 

 Dymond (1926) records having taken specimens as deep as 50 fathoms. 



SEASONAL MOVEMENTS 



The fishing season begins when the ice leaves (usually in early May) and con- 

 tinues until the lake freezes in late November. According to the fishermen, most 

 of the lake is relatively shallow, with holes of 25 to 35 fathoms scattered here and 

 there. There is water as deep, at least, as 67 fathoms off Livingston Point, but 

 areas covered by such depths are relatively limited. In spring the fishermen set 

 their nets on the banks of these "bowls" in 17 to 35 fathoms and through the season 



