Another week, another federally listed threatened or endangered species! This past week we were introduced to the threatened fluvial bull trout (Salvelinus confluentus) of Deming Creek. The bull trout of this particular region fall within the Upper Sprague River core area of the Klamath Recovery Unit. Deming Creek is believed to support the largest local population of the species in the Upper Sprague River core area, with high relative abundance, quality habitat, and a stable population number. Deming Creek is also unique in that it is free of nonnative brook trout (Salvelinus fontinalis), a congeneric species that competes and often hybridizes with bull trout.
Our goal for the next two weeks is to determine just how effective backpack electrofishing is in achieving a high recapture percentage in bull trout, and therefore a higher confidence interval in population size. We are sampling two hundred meter reaches of Deming Creek in two day increments; the first day being the capture and mark portion of the study, with the second day acting as a 24 hour buffer for the fish to re-acclimate to their habitat. The second day we will conduct the same survey of the reach, walking upstream and e-fishing and capturing any fish we see. By comparing the recapture counts to the previous day’s capture numbers, we get a percentage of our productivity, with that goal to better understand the confidence interval of our population estimate.
After about an hour and a half drive east of Klamath Falls toward Gearhart Mountain, we entered Winema National Forest, and the location of our survey site. We began by setting up an initial block-net that spanned the creek from bank to bank. We configured another identical net two hundred meters upstream from the first with the purpose of maintaining the same density of fish within the two nets for the duration of our sampling. Starting at the lower block-net, the four of us (Nolan, our mentor; Jenny; Brianne; and I) began the arduous journey across the slippery rocks and deceptively tumultuous riffles in search of any flash of the white underbelly of a trout that has lost equilibrium due to the electric current.
Within the first twenty seconds we’d caught our first fish: a 124mm red band trout! The next three hours entailed rotating of tasks between the four of us — electrofisher, first netter, second “ghost netter” and bucket holder — the latter being the most awkward of the four as you are the one to transfer each catch to the bucket while protecting the bucket from the imminent and inevitable dangers of capsizing through your own demise due to the slippery creek bottom.
I think my favorite role is that of the primary netter, but as Jenny and I were reflecting on how reminiscent this week has been to our pasts of playing high school and college sports, I was reminded of how gratifying and crucial each role is to the greater purpose of the team. The thrill of netting a >200g red band or bull trout is palpable as Brianne locates the convulsing fish, Jenny lunges forward towards the anode for it and I shriek with excitement when I realize it’s a recapture from the day before as I gingerly transfer it to my bucket.