ODFW has been conducting annual fish species monitoring at Diamond Lake and has expanded efforts in accordance with the 2006 FEIS. Biologists set large trap nets at the standard sites around the lake to capture fish moving during the night. In some years, ODFW also conducts both backpack and boat electro-fishing in the lake and its tributaries.
These techniques help the agency monitor fish growth and condition as well as determine what species are present and how abundant they are in Diamond Lake. Other studies are conducted as needed such as rotary screw traps to look at fish out-migration and stomach contents studies to look at what food items are present in fish stomachs during different times of year.