GREAT LAKES COREGONIDS 



373 



latitude of Goderich to the Straits of Mackinaw. I have not seen longjaws from 

 the Canadian waters of Lake Huron, but A. Purvis, of the Duck Islands, tells me 

 that he not uncommonly takes large "chubs" in 43^-inch gill nets set for trout 

 and whitefish off the Duck Islands in the north end of the lake in 20 to 30 fathoms 

 (record 45). His books show that the trout lifts for several years during the months 

 of May, June, July, and August frequently took from 100 to 200 pounds of gilled 

 chubs. The size of these fish indicates that they were longjaws. In spite of the 

 lack of other records for the Canadian side of the international boundaiy, an exami- 

 nation of the hydrographic chart of the region shows similar physical conditions 

 on both sides of the boundary line and leaves no doubt that the range of the longjaw 

 extends to near the Canadian shore. 



North Channel. — I have seen no longjaws from this region, but John Merrylees, 

 of Gore Bay on Manitoulin Island, tells me that he takes large "chubs" not uncom- 

 monly in 43^-inch nets in 20 to 25 fathoms (record 46). A similar statement 

 is made by D. Beneteau, of Thessalon (record 47). There is in the North Chan- 

 nel a maximum depth of 28 fathoms, shown on the chart. As neither chubs nor 

 blackfins are known to occur in quantities in less than 50 fathoms, these Gore Bay 

 and Thessalon fish must be either longjaws or short-jawed chubs. 



Georgian Bay. — All but 2 of the 11 records for this area were made by me from 

 the hauls of 3-inch gill nets of boats entering the ports of Lions Head and Wiarton 

 on the eastern shore of the Saugeen Peninsula. They show that the longjaw is 

 found in Georgian Bay in summer and fall at depths corresponding to those at 

 which it occurs in Lake Huron. There is no reason to suppose that it does not 

 range over the whole of Georgian Bay during this season at similar depths. Records 

 54 and 55 are from my own observation in late November and December, 1919, 

 and show the fish then in shallow water in Colpoy Bay at a depth of 10 to 25 fathoms. 

 The entire catch of the nets at this time was made up of longjaws, and all were 

 spawners and milters. According to the statements of Stanley Boyd, of Oxenden 

 (record 53), this spawning run was already in the bay when he put in his nets on 

 November 19. Record 58 is from the statement of Duncan Mclnnis, of Meaford. 

 It shows an inshore run of spawning fish in Owen Sound and between Meaford 

 and Cape Rich, both south of Colpoy Bay. These data on spawning fish are dis- 

 cussed in another place. 



From the data given in the table it may be concluded that the longjaw ranges 

 over the whole of Lake Huron and over Georgian Bay and that it probably occurs 

 in the North Channel also. It appears further from the records that in Georgian 

 Bay in late November and early December there is an inshore run of spawning 

 fish. 



BATHYMETRIC DISTRIBUTION 



The records so far discussed have dealt chiefly with catches taken in the chub 

 nets at depths of 35 to 100 fathoms. I have attempted, from other evidence, to 

 determine whether longjaws occur at depths of less than 35 fathoms. For this 

 purpose information is available from the following sources: (1) Catches of 13^-inch 

 gill nets set by hook fishermen off Alpena and Harbor Beach, Mich., for the purpose 

 of taking small fish for bait; (2) catches of 4^-inch gill nets set for trout and white- 

 fish in less than 35 fathoms at Alpena, Mich.; (3) catches of 2%-inch gill nets set 



