Figure 60.— Carp Lake River dam and inclined-screen-trap in opera- 

 tion during winter months. Trap box has been removed 

 and replaced by a baffle across the foot of the 

 inclined screen, February, 19h9' 



and a period of greatest activity during late March and early April, 

 During the intervening winter months, at least a few come downstream 

 nearly every dayj sudden minor spurts of activity may occur during 

 this winter period. 



All increases in migratory activity appear to be associated 

 closely with rising water levels. Late fall rains with resultant 

 increases in volume of flow bring down the initial surge of newly- 

 transformed individuals. Flood conditions resulting from mid- 

 winter thaws are likewise accompanied by sudden increases in down- 

 stream movement in that season. The greatest peak of downstream 

 migration occurs on the rise and crest of the floods resulting from 

 the general spring break-up in late March or early April. For this 

 reason, the calendar dates of this migration will vary from year to 

 year and from one watershed to another according to existing cli- 

 matic conditions. 



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