During the sampling, fish will be stunned and netted so biologists can record the size, condition and abundance of both redband trout and mountain whitefish. The fish are then released unharmed.
According to ODFW biologist Tim Porter, electrofishing can affect fishing in the portion of the river being sampled but angling in the remainder of the river should be unaffected.
The annual population assessment estimates the number of fish greater than or equal to 8-inches long per river mile for redband trout and mountain whitefish. In 2012, the number of redband trout per mile increased from the previous year to 5,244 fish per mile. The number of mountain whitefish per mile also increased to 6,578 fish per mile.
ODFW began sampling the Crooked River in 1989 in order to track the long-term health of the redband trout population.