376 



BULLETIN OF THE BUREAU OF FISHERIES 



half of this species. Within Georgian Bay at Wiarton and Lions Head, on July 28 

 and July 30, 1919, at 52 and 60 fathoms, respectively (records 51 and 48), hauls were 

 less than half longjaws. At Lions Head on October 6, 1919, in 70 fathoms (record 49), 

 there were few longjaws. In Colpoys Bay from November 28 to December 3, 1919, 

 in 10 to 25 fathoms (records 54 and 55), nothing but longjaws was taken. These, 

 which were all spawning fish, are discussed under breeding habits. 



The evidence reviewed shows without doubt that the longjaw is found in varying 

 numbers, when not spawning, at depths of 14 to 100 fathoms. Lifts made from 

 water 60 to 80 fathoms near the center of the lake, from 60 to 100 fathoms 17 to 20 

 miles northerly from the mouth of Thunder Bay, and from 70 fathoms in Georgian 

 Bay show but few individuals of the species. Those made in water of less than 50 

 fathoms with 2%-inch nets show either no individuals of the species or very few. 

 With 1^-inch nets small specimens have been taken commonly at 31 fathoms. The 

 heavy hauls of longjaws recorded are from depths of 50 to 64 fathoms, usually near 

 shallow-water areas. These show the species to make up 20 to 50 per cent of the 

 total number of fish taken. Only the catches of the 43^-inch gill nets recorded by 

 me, the use of the special 2%-inch nets (see p. 374), and the reports of the fishermen 

 indicate the presence of the fish in water of less than 30 fathoms outside of the spawn- 

 ing season. These records indicate that only small quantities of fish are taken. 

 The records thus show that the longjaw population, except in the breeding season, 

 has its greatest density at depths of 50 to 64 fathoms, and that the density decreases 

 toward deeper water and toward shore until only occasional fish are taken at 100 and 

 14 fathoms. Certainly more data are needed to determine finally the relative 

 density of the longjaw population at different depths. 



BREEDING HABITS 



Concerning the further natural history of the form little is known. That the 

 species leaves the north end of the lake toward the last of September seems certain, 

 as the boats from Cheboygan and Rogers take practically none at this time. (See 

 Table 14.) Whether the cause of the disappearance is simply an inshore movement, 

 and whether similar movements occur at the other ports of the lake, must remain 

 unknown until facilities for further observation are available. Certainly there is 

 an inshore movement in Georgian Bay when (during the first week of November) 

 swarms of spawning fish enter Colpoys Bay in 10 to 24 fathoms (records 53 to 

 55). The fish are also said to be present at the same time in Owen Sound and be- 

 tween Meaford and Cape Rich in 16 to 20 fathoms (record 58). The records of 

 stray individuals in 3 fathoms in Saginaw Bay on October 29, 1921, and on Novem- 

 ber 25, 1925 (records 41 and 42), show that some individuals come into still shallower 

 water at this time. The bottom of the grounds then visited is broken, according 

 to the fishermen — that is, it consists of "mud" mixed with rock and gravel. During 

 the last week in November, 1919, I found spawn flowing freely from the females 

 and pearl organs on the males taken in Colpoys Bay. There can be no doubt that 

 the fish frequent these localities at this time for the purpose of depositing their eggs. 

 In 1919 the fish were caught from November 19 to December 3 in Colpoys Bay. 

 They left during a heavy gale the first week in December. On account of the rough 



