Electrofishing the Ranch

The Idaho Department of Fish and Game (IDFG) will be electrofishing the Ranch over the next couple of weeks to obtain fall population estimates.

To estimate the Ranch population, IDFG will use a "mark-release-recapture procedure" in which a sample of the fish population will be captured from the river by electrofishing from a raft. When caught, each fish will be marked (usually by clipping a fin) and then be released back into the river to mix with the remainder of the population. Later, a recapture procedure will be repeated in which the proportion of marked individuals in the second sample can be used to estimate the number in the total population. Marking runs will take place from the Log Jam downstream to Osborne bridge today and tomorrow (October 6th & 7th) and the recapture run will occur next week (October 15th and 16th).

These estimates will be compared to those obtained in the spring to see how fish hold in the Ranch later in the season when macrophytes have become well established.