Juvenile salmon outmigration season is underway! As the young fish make their way through the rivers and out towards the ocean, we monitor their population with the help of rotary screw traps. Today’s Film Friday selection shows you how we mark some of the fish we capture with photonic dye. The number of marked fish that we recapture helps us calculate how efficient the trap is. Working together, we were able to mark 2,500 fish in a single day!