GREAT LAKES COREGONIDS 



441 



Kiyi has also a narrower body and a much longer maxillary, snout, and mandible. 

 The latter is usually equal to or shorter than the upper jaw in artedi and longer 

 and hooked in Tciyi. Artedi is also more pigmented, especially on the dorsal surface. 



GEOGRAPHICAL DISTRIBUTION 



All my data on the occurrence of the kiyi in Lake Huron are given in Table 

 50 and are platted in Figure 5. There are 20 records made during three years and 

 show the species to occur in Georgian Bay and in the central basin of the main lake. 

 At each end of the lake the water becomes shallower, and probably conditions are 

 less suitable there. 



BATHYMETRIC DISTRIBUTION 



The sources of the data on depth distribution of Tciyi are, for the most part, the 

 2%-inch chub nets that are set at depths of 60 fathoms or more. A few specimens 

 were taken in a special set of l^-inch net made on September 13, 1919, off Presque 

 Isle Light in 60 fathoms (record 11). Chub nets took specimens in 1917 on 

 September 7, 12, and 21 and on October 17 and 20, and on September 18, 1919, in the 

 center of the lake east of the Alpena can buoy in 65 to 80 fathoms (records 1, 2, 8, 

 9, 10, and probably 13); on September 14 and 19, 1917, in the center of the lake 

 northeast of the can buoy in 65 to 80 fathoms (records 3 and 5); on September 18, 

 1917, 17^ miles N. by E., on September 20, 1917, 14 miles NE. by E., on September 

 21, 1917, 17 miles NE. by N. % N., on September 18, 1919, 14 miles N. by E., on 

 June 30, 1923, 17 miles NE. by N. % N., on July 5, 1923, 18 miles NE. % E., and 

 on July 7, 1923, 13 miles NE. Y 2 N. of Thunder Bay Island in 60 to 100 fathoms 

 (records 4, 6, 7, 12, 14, 16, and 17); and on July 2, 1923, 20 miles E. by N. of the 

 can buoy in 60 to 70 fathoms (record 15). In Georgian Bay specimens were taken 

 on July 30, 1919, 21 miles east of Surprise Shoal and off Wiarton in about 60 fathoms, 

 and on October 6, 1919, off White Bluff in 70 fathoms (records 18, 19, and 20). A 

 comparison with Tables 18 and 58, which give distribution data for johannse and hoyi, 

 shows that not all lifts of the chub nets took Tciyi. Three lifts off Cheboygan, Mich., 

 at the north end of the lake, and one off Harbor Beach, Mich., at the south end of the 

 lake, in 35 to 50 fathoms, took no Tciyi; nor were Tciyi always present in the lifts of the 

 chub nets made off Alpena in more than 60 fathoms. No Tciyi ever were seen among 

 the small fish taken in the l^-inch bait nets off Cheboygan (one lift), Alpena (two 

 lifts), and Harbor Beach (two lifts); nor were any included among the small fish 

 taken on eight occasions by the 43/2-inch trout and whitefish nets off Alpena set in 

 30 fathoms or less. (See Table 58.) It appears likely, therefore, that Tciyi prefers 

 only the deeper waters and occurs, during most of the season at least, only at depths 

 of more than 60 fathoms. 



RELATIVE ABUNDANCE 



The kiyi has absolutely no commercial significance in Lake Huron, and there- 

 fore its relative abundance, as compared with that of the chubs, is of no interest. 

 Inasmuch as virtually all the specimens collected have been found accidentally 

 ensnarled in nets of a mesh too large to gill them, their number in these nets is no 

 satisfactory index of their abundance; there are no data on the absolute abundance 

 of the species, except that a 13^-inch net about 350 feet long, lifted from 60 fathoms 



