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BULLETIN OF THE BTJAREU OF FISHERIES 



(3) The third source of evidence as to the spawning season is the testimony of 

 several fishermen who have taken spawning runs of chubs in September. Fishermen 

 at Tobermory and Lions Head on Georgian Bay assert that many of the fish taken in 

 their nets during the month of September off the Saugeen Peninsula in 60 fathoms on 

 mud bottom are full of loose spawn and that at this period their lifts are often nearly 

 doubled in weight. This would seem to indicate that a spawning run had entered the 

 nets. Zenithicus is the only fish in the lake known to spawn in September, but its 

 spawning season in Lake Huron does not begin before the middle of September and 

 continues until the middle of October, and it is not likely, therefore, that these fish 

 are of this species. Besides, zenithicus is not known to be common in Georgian Bay. 

 Nigripinnis and alpense do not spawn before November, so that these species certainly 

 are not concerned in the phenomenon described, and the spawning fish can only be 

 chubs. 



There can be no question then that the spawning period of the chub begins 

 the last of August and continues into September: (1) The schools of fish begin to 

 leave their feeding grounds the last of August and are absent during September. 

 Only the nonspawning individuals and a few spawning fish remain behind. (2) Fish 

 caught in July and early August have eggs in an advanced state of maturity. From 

 the last of August and through September females have either only ripe or only 

 undeveloped eggs. In October the fish taken have only undeveloped ovaries. 

 Pearled males were taken on October 6, 1919. (3) A spawning run of fish, which 

 must belong to this species, has been reported in Georgian Bay in September. 



It remains to find the spawning grounds. If the Georgian Bay fishermen 

 actually get the fish where they are spawning and not while they are moving to the 

 spawning grounds, then the situation of at least one of the spawning places in Georgian 

 Bay is established. (It is interesting to note, in this connection, that a lift examined 

 on October 6, 1919, on these reported spawning grounds (record 35) had very few 

 chubs in it and that these were spent.) We still have, then, the Lake Huron indi- 

 viduals to account for. It is not likely that the schools from the lake traverse the 

 shallow water off Cape Hurd to get into Georgian Bay. In that case they must 

 spawn somewhere in the lake. With no more data than are now available it is not prof- 

 itable to speculate as to where these spawning grounds might be. It is better for the 

 fish, of course, that this gap in our knowledge of their habits has not been bridged. 



FOOD 



Carl L. Hubbs, of the Museum of Zoology, University of Michigan, has examined 

 a series of stomachs of coregonids collected by me on Lake Huron, and his report is 

 given under this heading for each of the Lake Huron species. Doctor Hubbs finds, in 

 an examination of 34 stomachs of johannse collected off Alpena, Mich., in 65 to 70 

 fathoms in September and October, 1917, that the chief article of diet is Mysis. 

 This animal constitutes from 80 to 100 per cent of the food in most of the stomachs. 

 Pisidium and Pontoporeia are present in about one-third of the examinations, usually 

 only in relatively small quantities. Half of all specimens had ingested sand, cinders, 

 and wood fragments. Other objects casually swallowed include adult insects, larval 

 and pupal Chironomidse, and fish scales. 



