468 



BULLETIN OF THE BUREAU OF FISHERIES 



The body shape of Tioyi is also less elongated, the flesh is softer, and the color 

 is likely to be paler. The state of the sex organs also may serve to separate the 

 smaller individuals, as hoyi matures at about 130 millimeters while few artedi are 

 mature under 200 millimeters. 



GEOGRAPHICAL DISTRIBUTION . 



All my data on the occurrence of hoyi in Lake Superior are given in Table 60. 

 They are shown in Figure 3 platted on a map of the lake. The 16 records were made 

 chiefly from nets of to 4% inch mesh, in which individuals were ensnarled acci- 

 dentally; but on two occasions the catches of the l^-inch bait nets were examined. 

 There are sufficient data to warrant the conclusion that the bloater occurs through- 

 out Lake Superior and even in the north bays where suitable conditions are found. 



BATHYMETRIC DISTRIBUTION 



Only by the use of lj^-inch nets can it be ascertained definitely what are the 

 limits of the bloater's zone of distribution. No lifts of these nets were seen by me 

 from less than 40 fathoms. Nets of 2^ to 4 Y2 inch mesh were lifted on several 

 occasions from shallower water, and in several such gangs bloaters were caught. 

 They were not present in two lifts of such nets made in September from 11 and 14 

 fathoms, but occurred in several lifts set as shallow as 15 to 20 fathoms. From 

 depths of more than 40 fathoms, where the nets were set on a bank and extended 

 from shallow water to depths of 90 fathoms, specimens were taken in the l}/2 to 4}/£ 

 inch nets. The only specimens taken in depths of 80 to 90 fathoms, where such 

 depths did not occur immediately at the foot of a bank, were caught in a lift made 

 off Bread Rock, Ontario, on October 4, 1921, in 80 to 90 fathoms (record 15). 

 Five other lifts of gangs of such nets made off Grand Marais and Marquette, Mich., 

 Michipicoten Island and Coppermine Point, Ontario (see Table 24), from depths 

 of 60 to 100 fathoms, took no bloaters among the small fish accidentally captured. 



It is likely, then, that the bloater ranges along the banks down to depths of 

 90 fathoms but does not wander out into the vast areas that are covered by such 

 depths. How close to shore it goes is not known, but in summer specimens have 

 been taken as shallow as 15 fathoms. 



RELATIVE ABUNDANCE 



In Lakes Michigan and Huron the species appears to prefer depths of about 

 30 fathoms for the greater portion of the year, but in Lake Superior there are very 

 restricted areas of shoal water and the descent from shore to the plains (which are 

 overlaid by depths of 60 to 100 fathoms and more) is abrupt. It is on these banks 

 that the species has been found most abundantly. Thus, in the 4K-inch nets, which 

 in the 2 or 3 miles of their length extended from depths of 40 to 90 fathoms, speci- 

 mens were occasionally or commonly found entangled, namely, on July 14, 1922, 

 25 miles north of South Twin Island, Wis.; on July 15, 1922, 14 to 18 miles NW. by 

 N. of South Twin Island and 20 miles northwest of Rocky Island, Wis.; and on 

 September 14, 1921, and July 17, 1922, off Terrace Point, Minn, (records 6, 7, 8, 

 10 and 11). Occasional specimens were taken similarly on August 24, 1921, 21 

 miles west, and on August 25, 1921, 6 miles NNW. of Ontonagon, Mich., in 15 to 45 

 and 20 to 38 fathoms, respectively; on July 17, 1922, 20 miles NE. by E. of Duluth, 



