From The Cortez Journal (Jim Mimiaga):
Aquatic biologist Jim White, of Colorado Parks and Wildlife, spoke at a community meeting in Dolores about planned fish surveys, population data and survey techniques.
Parks and Wildlife works with McPhee Reservoir managers to manage downstream flows for three native species that reside in the Lower Dolores – the roundtail chub, bluehead sucker and flannelmouth sucker. The first several miles below the dam to Bradfield Bridge is managed as a cold-water fishery for brown and rainbow trout.
“Roundtail populations have been good,” White said, “and bluehead and flannelmouth are not as abundant.”
The reservoir holds a 33,500 acre-foot reserve for the native fish needs. The “fish pool” is released gradually throughout the year base on biologists’ input. In the winter, flows below the dam are 20-30 cubic feet per second. During summer, they reach 60-80 cfs if there is no whitewater release.
During low water years, the fish pool and farmers share in shortages. When there is a recreation dam release like this year, it is not counted against the fish pool, and the higher flows are managed for ecological benefits such as channel scouring, timing to benefit the fish spawn, and flood plain sedimentation that replenishes nutrient rich sediment on the banks for new seedlings…
Fish counts and surveys are done each year at Slick Rock Canyon, Dove Creek Pump Station, Pyramid Mountain and below the San Miguel confluence.
White explained how a “pit-tag array” installed in 2013 to monitor native fish on the Lower Dolores River works. It is just upstream from the Disappointment Creek confluence.
Native fish captured throughout the Lower Dolores are inserted with a electronic tag, and when they move past the “array” wire above the river, the movement and fish identification is recorded.
So far, 1,421 fish have been tagged. Of those, 38 percent were flannelmouth suckers, 35 were roundtail chubs, and 23 percent were bluehead suckers. Four percent were smallmouth bass, a non-native species biologists are trying to get rid of because they prey on young native fish.
Since installed, 157 tagged fish have been recorded passing under the pit-tag array. In 2018, 14 fish were detected, including eight flannelmouth that arrived after April 8. Five of the flannelmouth were tagged in Slick Rock Canyon, two in the Pyramid Mountain Reach and one tagged in 2014 in the San Miguel River.
The first native fish of 2019 passed under the array on April 5. It was last detected on Oct. 18. On April 16, two flannelmouth were recorded.