Once spawning is done the adult out migration begins right away. The Young of Year head downstream in September and October

On the Move

From the mouth of the Sebasticook to MerryMeeting Bay will be several days.  They generally move at waters pace give or take.  E.g. water from the Burnham Dam takes 12 hours to reach the Benton Dam.   That will give you an idea of transit time.   They will eat, constantly eat and grow.  The drive to leave the system is multifold as we’ve discussed.  There will be a massive exodus from the system into the Gulf of Maine proper after this huge rain event we’re going to get Thursday PM into Friday PM.  This will swell the river over a 48hour period and this increase in flow and drop in temp will “encourage” the YOY (young of the year) to split into the near shore waters of the gulf where they will continue their pursuit of food for the next four years.  

Nate Gray 2014

The outmigration has some dangers other than predators. The fish will have to get past the dams coming downriver. Some of the fishways have provision for the outmigration like bypasses. The fishways are opened up for heading back downstream as well. Sometimes the fish just head over the dams. They are driven to get downstream and they will do what is needed.