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Issue link: http://mag.outdoornebraska.gov/i/999185
JULY 2018 • NEBRASKAland 45 O The fish bypass at Spalding Dam is not the first in the state. That honor goes to one built in 1993 at Belmont Dam on the North Platte River near Bridgeport. Fish tagging studies there, however, have not yielded returns, leaving biologists unsure as to whether it is working as intended. In 2005, another built at Milburn Dam, a diversion on the Middle Loup River, showed promising results early, with catfish being caught upriver in places they hadn't for years. That fishway hasn't been operated recently, however, due to sediment loading above the dam. Commission biologists wanted to make sure the fishway at Spalding was allowing fish to move upstream, and also wanted to know what species, how many, how often and when they were using it. In 2016 and 2017, they caught and tagged fish by deploying hoop nets and electrofishing barges in the river and the tailrace of the wheelhouse, as well as cutting flows to the fishway, trapping fish in it. The study used PIT tags, tiny transponders injected under the skin of the fish just like the "microchips" used to identify dogs and cats. Tag readers were installed at the upper and lower ends of the fishway to record when fish passed, allowing biologists to determine the direction they were traveling and the time it took them to ascend or descend the fishway. In 2016, 321 fish of 10 species were tagged, including 141 channel catfish, and only 31 passed through the fishway. Things improved in 2017, with 52 of those fish making it through. Things were even better for fish tagged in 2017, with 382 of the 620 fish, 61 percent, making it upriver. That included 242 of the 305 catfish, 79 percent, making the trip. "You really have no expectations," Schainost said of his thoughts going into the study, "but my feeling is if you get over 40 or 50 percent [of the fish passing through the fishway] you're doing well. So the fishway is working great." Flathead chub, river carpsucker, shorthead redhorse, largemouth bass, walleye, white sucker, quillback and common carp all made it through the fishway. The only tagged species that didn't was northern pike. "So it was very interesting to find out that a lot of our native fishes can handle a fishway designed for a salmon," Schainost said. The study also resulted in other interesting observations. Some species took much longer than others to make it through the fishway, with most taking less than an hour but one taking nearly 8 hours. With the tag readers located on a baffle next to one of the resting pools the first year, biologists could see that fish often circled in the pool for some time before moving on. One circled 33 times in 90 minutes. One river carpsucker tried one day and failed, but was successful three days later. One catfish has made four round trips through the fishway. Five catfish, five shorthead redhorse, four river Engineering drawings detail the site plan for the fishway at Spalding Dam. Fish enter the fishway from the Cedar River and navigate three 21- to 26-foot long, baffle-filled chutes built on a 13.5 percent slope, three resting pools and a culvert to reach the lake above the dam. Commission Fisheries Biologist Steve Schainost of Alliance passes a young channel catfish netted in the Cedar River below Spalding Dam in front of a PIT tag reader as Brett Roberg records the tag number, length and weight of the fish.