Iron River National Fish Hatchery
Midwest Region
                   
                   
       




Eyed Eggs
Once the eyes of the developing fish are visible, the eggs are hardy enough to be run through an egg picker (sorting out the dead eggs) and placed into egg jars or shipped to other fish hatcheries.

 




Sac Fry

The eggs begin to hatch about 60 days after they are eyed (depending on water temperature).  The yolk sac remains for about 30 days, until all the nutrients are absorbed.  During this stage, the fish remain lying on the bottom of the tanks unless disturbed.

 




Green Eggs

After fertilization, the eggs are very sensitive to movement and cannot be disturbed for about 30 days (until they are “eyed”).

   
     
     
               









Swim-Up Fry

Once most of the yolk sac is absorbed by the fish, they will swim up to the water surface to feed.

               
 

 

 

Mature Adults

Fish are considered to be mature once they are able to spawn.  Lake trout spawn after 5-6 years.  Coaster brook trout spawn after 3 years.

         
               
                   
     

Yearlings

After the fish are 1 year old, they are generally stocked into lakes and streams.

 

Fingerlings

As the fish continue to eat, they are considered fingerlings from 1 inch in length to 1 year of age.

       
       
       
                   

 

Last updated: July 22, 2008