398 



BULLETIN OF THE BUREAU OF FISHERIES 



2, 1923, 20 miles E. by N. of the can buoy, and July 5, 1923, 18 miles NE. % E. of 

 Thunder Bay Island (records 30 to 33). On October 27, 1917, 35 miles NE. by N. 

 % N. of Harbor Beach, Mich., in 50 fathoms (record 36), it was also rare. In three 

 lifts made in 60 to 64 fathoms on August 30, 1919, 18 miles N. by E. E. of Thunder 

 Bay Island, September 3, 1919, 28 miles E. x /i S. of the can buoy, and July 7, 1923, 

 13 miles NE. Yi N. of Thunder Bay Island, zeniihicus comprised 14 to 17 per cent of 

 the catches. In Georgian Bay it has been found absent or rare among the fish seen 

 in seven lifts of the 3-inch nets, the number not including the sets on the spawning 

 grounds of the longjaw (records 38 and 39.) 



In less than 35 fathoms the 4^-inch trout nets, the lj^-inch bait nets, and the 

 2%-inch chub nets set under my direction with the 4j^-inch gangs have taken the 

 species. While it never was abundant or even common in the 4j^-inch nets off 

 Alpena, Mich., in September, 1917, and in July, 1923, there are more records for it 

 in these nets than for any other species of chubs. (Records 9, 11, 12, 13, 14, 22, 

 and 35.) The 2%-inch nets set with the trout nets brought in only one fish on 

 September 17, 1917, from 15 fathoms (record 16), and September 26, 1917, from 17 

 fathoms (record 23); six on September 19, 1917, from 30 fathoms (record 19); and 

 none on November 2, 1917, from 15 fathoms. Thus the fish were not shown more 

 abundant by these nets than by the 43^-inch nets. In the lj^-inch bait nets at 30 

 fathoms occasional specimens were taken off Cheboygan, Mich., on October 15, 

 1919 (record 4), and off Alpena, Mich., on September 8, 1917, and September 16, 

 1919 (records 10 and 29). Off Harbor Beach, Mich., on March 15, 1919, 12 per cent 

 of the small fish examined from a catch of the bait nets were zeniihicus (record 

 37). A single specimen was taken in the special l^-inch net set off Presque Isle 

 Light in 60 fathoms on September 13, 1919 (record 28). In view of the fact 

 that the fish spawn in 35 to 50 fathoms, it would be expected that immature fish 

 would be more common in these nets than the records show. However, the evidence 

 from this source is scant and is by no means conclusive. 



All the records thus indicate that during the summer and early fall zeniihicus is 

 not common in nets of any class except in the 2%-inch nets set on its spawning 

 grounds in the north end of the lake. It should be noted, however, that most of the 

 records indicating relative abundance have been made during, shortly before, or 

 after the spawning period, which falls between the middle of September and the 

 middle of October. If zeniihicus, like most other fish, seeks spawning grounds in 

 water shallower than that in which it feeds, then the maximum density of its popula- 

 tion may be looked for at depths greater than 35 to 50 fathoms. 



BREEDING HABITS 



Only in 35 to 50 fathoms northward from Forty Mile Point were zeniihicus found 

 abundantly. On September 28 and 29 and October 14, 1917, lifts from these grounds 

 examined by me contained this species almost exclusively. At this period the fish 

 were spawning. Males were taken with pearls, and females were full of ripe eggs, 

 except on the latest date, when many were nearly spent or spent. The fishermen say 

 that the fish begin to move onto the clay bottom between Spectacle Reef and Forty 

 Mile Point in 30 to 50 fathoms toward the middle of September. At first they run 

 into 30 fathoms but move out later to 40 to 50 fathoms to spawn. Records of the 



