BREEDING HABITS. 65 



If each age-class of smolt is wholly or predominately produced in a separate section or 

 a different tributary, as it may well be, the situation would be analogous to separate 

 rivers where onlj^ one or another age-class is represented. Any falling off in the runs, 

 as expressed by the fishery, might be due, in part at least, to absence of salmon represent- 

 ing one or the other of the age-classes of smolt rather than to a reduction of all age- 

 classes. 



Breeding Habits. 



Miescher-RUsch (1883, p. 432) stated that: 'According to Mr. Glaser's experience, 

 which extends over many years, and which is corroborated by my own observations, 

 extending over a period of eight years, the normal spawning season at Basel for the over- 

 whelming majority of all fish may be said to last from the middle of November till the 

 middle of December.' Calderwood (1907, p. 12-13) says that in Scotland there is con- 

 siderable variation in the Umits of the spawning season, varying from a month to two 

 and a half months according to the number and character of the streams taken into ac- 

 count. In the earUest rivers the height of the spawning season occurs about November 7, 

 which is one month earlier than in the latest rivers. For Great Britain generally, Day 

 sets the spawning period between the middle or last week of October and the middle 

 of February or later. Gilpin finds that salmon spawn in the latter part of November 

 in Nova Scotia. According to Livingston-Stone the season commences about the 

 middle of October in the Miramichi River, New Brunswick, although Perley reports 

 that the salmon spawn in the Southwest Branch of the Miramichi in November. Atkins 

 states that in the Penobscot spawning appears to begin during the last week in October 

 and very seldom is delayed until after November 10. But he said a good deal depends 

 upon the stage of water. If the water is low, the salmon will wait until rains raise it. In 

 1931 the date of fertUization of the eggs in hatcheries on seven Canadian rivers in the 

 Maritime Provinces varied from October 24 to November 15. 



In 1839 Shaw (1840, p. 565) wrote: 'The female, regardless of the occasional absence 

 of the males during these contests, and probably satisfied with the presence of the male 

 parrs, proceeds with her operations by throwing herself at intervals of a few minutes 

 upon her side, and while in that position, by the rapid action of her tail she digs a re- 

 ceptacle in the gravel for her ova, a portion of which she deposits, and, again turning 

 upon her side, she covers it up by a renewed action of the tail, — thus alternately dig- 

 ging, depositing, and covering ova, until the process is completed by the laying of the 

 whole mass, an operation which generally occupies three or four days.' 



Calderwood (1907, p. 14-15) says that he is 'incUned to estimate that on an average the 

 female salmon completes her reproductive functions in a week or ten days. In small 

 streams the time may be shorter.' Atkins says that a female salmon can retain her eggs 

 for three weeks after they are ready to be laid, with Uttle or no injury to them. 



In nature all the eggs are not extruded at once, because all the eggs in the ovaries do 

 not become ripe simultaneously. The eggs at the posterior extremity of the ovary be- 



