The antennas are working!
After a lot of trial and error the stationary PIT antenna system is up and running at the lower site in Haga å, Billdal. We faced several challenges getting the antenna in place at this site, from electrical interference in the tunnel to logs in the stream tearing them down during bad weather. But now, finally, there are functioning antenna where we need them to see the juveniles migrate to sea. Just in time too as the tagged juveniles will start to migrate in the next couple of weeks!
We built two antennas so we can determine which direction the fish are swimming in and be sure when they have migrated. The main objective is to see whether there is variation in migratory patterns between populations born very far upstream and those born closer to the river mouth. Things to look out for will be date of migration, time of migration, do they move in groups, what is the temperature in the stream when they migrate and do more bold individuals migrate faster?
Once they enter estuary the fish will likely stay in the local coastal area, here they will have access to nutrient rich food that will aid their growth. In a few years they will return to the stream system to spawn, by which time they will have grown much larger than their resident counterparts.