I know the SF, the middle, and north fork all have bull trout in the but I'm wondering about the main in town stretch. Someone recently told me they caught one a while back here and was wondering if that was possible? Also what is the largest rainbow and brown trout taken out of the in town stretch?
Thanks for your question about Bull Trout and the Boise River. Bull Trout are now mostly extinct below Lucky Peak dam. It is possible (but very unlikely) that a Bull Trout could be flushed downstream through Arrowrock and Lucky Peak dams and be caught in the lower Boise River. Bull Trout have not been documented in any surveys for probably over 50 years. It’s not impossible that you caught a Bull Trout, but it would be very rare!
I’m not sure what the largest Brown Trout ever caught has been, since we don’t keep angler records for individual waters. However, population surveys have occasionally found some rare Brown Trout in the 25-27 inch range. Jake Cecil caught a very large Rainbow Trout in 2007 directly below Lucky Peak dam. That fish was 30” long, with a 25” girth, and was estimated at over 23lbs. That is a very unusual trout for that stretch of the Boise River. Typically, anglers might expect to see Rainbow Trout up to 25 inches, but a rainbow over 22” is exceptional.