Access to important tributary habitats greatly assists the persistence of native Colorado River basin fishes. Historically, the Duchesne River was used extensively by Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus), which are now federally protected under the Endangered Species Act, as well as flannelmouth sucker (Catostomus latipinnis), bluehead sucker (C. discobolus), and roundtail chub (Gila robusta)(1,2), which are currently listed as Sensitive Species and Species of Greatest Conservation Need in Utah(3). Declines for these species have been most noticeable in heavily impacted mainstem and tributary rivers throughout their native range. This includes the Duchesne River, which has been significantly altered due to a multitude of water diversions and dams that substantially modify the natural hydrograph and thus a variety of ecosystem level processes. In addition, some diversion structures (e.g., Myton Diversion) create impassible barriers that limit migratory capabilities of the aforementioned species, thus disconnecting fish populations and limiting gene flow over time. Furthermore, Division personnel documented flannelmouth sucker in spawning condition immediately below the Myton Diversion structure in April 2009(4), suggesting that these fish were attempting to move upstream (presumably to historical spawning grounds). Construction of a fish passage structure at the Myton Diversion in 2015 has restored connectivity of fish populations above and below the diversion, adding more than 20 miles of historical spawning and rearing habitat to the lower Duchesne River, and helping restore natural ecosystem function in the Duchesne River watershed. However, the fish passage structure is designed for selective passage (i.e., allow movement of native species, removal of invasive nonnative fishes) using a series of fish traps and must be manually operated to pass native fishes either upstream or downstream during spring high flows when these fish are migrating to spawn. Without manual operation, benefits to native fishes from the construction of this passage structure will not occur. Additionally, in order to evaluate the success of the fish passage structure through time, it is imperative that the fish assemblage is assessed regularly to compare pre- and post-passage fish communities. Unfortunately, during the construction phase of the fish passage structure (funded from a variety of resources), operation and maintenance costs were unknown as was the level of effort from each agency responsible for future monitoring. Subsequently, UDWR's Northeastern Region Native Aquatics Program has inherited 100% of these responsibilities (i.e., partnered with the Ute Tribe who has been unable to assist with field activities). To ensure that this essential project occurs in addition to other mandatory tasks, we are requesting additional assistance from ESMF in FY 2022 and potentially beyond to specifically expand native species habitat and to monitor the effectiveness of this beneficial habitat alteration. 1 Bezzerides, N. and K. Bestgen. 2002. Status review of roundtail chub, Gila Robusta, flannelmouth sucker, Catostomus latipinnis, and bluehead sucker, Catostomus discobolus, in the Colorado River Basin. Larval Fish Lab Contribution 118, Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins. 2 Holden, P.B. and C.B. Stalnaker. 1975. Distribution and abundance of mainstem fishes of the middle and upper Colorado River basins, 1967-1973. Transactions of the American Fisheries Society 104:217-231. 3 UDWR. 2006. Conservation and Management Plan for Three Species Fish in Utah. Publication. 2006. Publication 06-17. Salt Lake City, Utah 4 Breen, M.J. and T.N. Hedrick. 2010. Conservation activities for bluehead sucker, flannelmouth sucker, and roundtail chub in four drainages of northeastern Utah. 2009 Statewide Monitoring Summary, Publication 10-25. Utah Division of Wildlife Resources, Salt Lake City, UT.

The main objective of this project is to provide fish selective passage at the Myton Diversion on the Duchesne River. Specifically, following the construction of a vertical slot fishway through the diversion structure to restore access to over 20 miles of the Duchesne River for native fish populations. We expect immediate habitat-use benefits for flannelmouth sucker, but also expect other native species with regular long-distance migrations to benefit as well from the addition of spawning and rearing habitat (seasonal use and year-round use). Based on operational experience and lessons learned from 2016 experimental spring operation, we plan on operating the Myton fish passage for 45 days in the spring of 2020, accomplishing a number of native species conservation objectives. Passage operation will allow for selective movement of native species above Myton Diversion, allowing historic locations to be reoccupied. It will also allow for targeted removal of invasive species including walleye, smallmouth bass, white sucker, and other problematic nonnatives. For our second objective, fish community surveys will be necessary both above and below Myton fish passage to evaluate the success of fish passage operations (i.e., pre- vs. post-passage community composition). This sampling will also allow for the opportunity to PIT tag fish to determine how fish are moving around the drainage. For example, do we see a shift in community composition as we allow additional native fishes access to upstream areas? (1) Operate Myton Diversion fish passage structure for 45 days (spring 2022). (2) Survey multiple sites using barge, boat, and cataraft electrofishing techniques to determine shifts in fish community composition this may include up running from the Green River Confluence when flows allow (fall 2022). (3) Provide a 5-year assessment report after spring 2022 operations. This will include data from 2016-19 and 2022.

Conservation of the three species in the state of Utah are related to both a rangewide and statewide conservation agreement and strategy plan. These plans are attached to the documents section but the specific activities addressed by this project that are included in the associated conservation agreements and strategies are outlined below including the action followed by an explanation of how this project addresses each specific action. Increase roundtail chub, bluehead sucker, and flannelmouth sucker populations to accelerate progress toward attaining population objectives for respective species. Explanation: This project increases populations of the three species by allowing access to 20 miles of previously cut-off habitat. Increasing populations reduces threats posed by genetic bottlenecks, and hybridization with invasive species. This project accelerates conservation of the three species in the Duchesne River above the Myton Diversion. Control (as feasible and where possible) threats posed by nonnative species that compete with, prey upon, or hybridize with roundtail chub, bluehead sucker, and flannelmouth sucker. Explanation: Manual operation of this fish passage structure allows for the selective removal of problematic non-native species. Of particular concern in the Duchesne River are white sucker and smallmouth bass. These along with other invasive species can be selectively removed thereby reducing the impact of invasive species. Expand roundtail chub, bluehead sucker, and flannelmouth sucker population distributions through transplant, augmentation (i.e., use of artificially propagated stock) or reintroduction activities as warranted using a genetically based augmentation/ reestablishment plan. Explanation: This project is not a typical reintroduction plan through a stocking type of approach it does however expand the three species populations by allowing access to 20 miles of habitat that have been previously cut-off by the Myton Diversion. By providing passage we are expanding three species populations in particular Roundtail Chub and Bluehead Sucker which have been extirpated from the area above Myton Diversion. Establish and implement qualitative and quantitative long-term population and habitat monitoring programs for roundtail chub, bluehead sucker, and flannelmouth sucker. Explanation: This project has been ongoing including multiple years of community sampling prior to completion of the passage project. We also annually assess community following completion of the passage structure. This allows for a long term data set to evaluate the success of this project and how reintroduction effects overall community composition in the Duchesne drainage. This information can then be extrapolated to better understand how reintroduction efforts may work in other drainages.

The passage structure is situated on Ute Tribe lands and as such an access permit must be obtained in order for operation to occur. We will start the process of obtaining the necessary permit in February 2020 as it must be re-issued on an annual basis. Prior to construction of the Myton Diversion fish passage structure, the U.S. Fish and Wildlife Service (Utah Ecological Services Field Office) completed extensive efforts towards compliance of the Endangered Species Act during the development of a Safe Harbor Agreement and Candidate Conservation Agreement with Assurances (CCAA/SHA, attached for reference) for Colorado pikeminnow, razorback sucker, roundtail chub, flannelmouth sucker, and bluehead sucker. The Utah Division of Wildlife Resources is a signatory of this agreement.

Prior to construction of the Myton Diversion fish passage structure in 2015, fish community surveys via backpack, barge, and cataraft electrofishing were completed in the Duchesne River (above and below the diversion, during high and low flow conditions) to develop a comprehensive picture of the pre-passage fish assemblage. These surveys will continue as a monitoring component for this project (combined with fish passage operation). We plan to operate this structure during high spring flows (up to 45 days) when native fishes are actively migrating to spawn upstream. The selective passage feature of the structure consists of two individual fish trap fyke panels that can be manipulated as needed. By separating the two fyke traps with a center panel, we will create two individual traps: (1) one representing fish that were captured while moving in a downstream direction and (2) one representing fish that were captured while moving upstream. Field personnel will flush out the raceway of sediment and debris to begin each site visit, then the raceway will be closed while personnel conduct numerous net sweeps in each trap, noting the direction of travel for each fish captured. All native fishes will be PIT-tagged and released either upstream or downstream of the diversion depending upon which trap they were captured in. All nonnative fishes, regardless of which trap they were collected in, will be removed from the system. In 2021, a floor-lift system will be installed in the structure which will enable safer and more efficient operation during high flows. Methods for operation of the lift system will be developed upon its completion.

Seasonal (spring) passage use will be assessed using the bi-direction trap. Trap capture data will be merged with post-passage sampling above and below the diversion to monitor the success of the project.

Utah Division of Wildlife Resources U.S. Fish and Wildlife Service Ute Indian Tribe U.S. Bureau of Reclamation Central Utah Water Conservancy District Associated Water Users of the Duchesne and Strawberry Rivers

The structure was installed to provide passage for the life of Myton Diversion. Currently, the structure operates as a selective passage, which is labor intensive. In some systems, the benefits of selective passage outweigh the costs (in accordance with the SHA/CCAA). We will assess the value of selective passage on the Duchesne River for five years of operation through 2022 season. Our assessment will detail upstream and downstream use of the passage for all species as well as changes in community composition above and below the passage. If after the assessment it is deemed that selective passage is not providing a greater benefit that open passage, we will remove the trap and only operate the gates and stop logs to ensure proper attraction flows. If selective passage is found to provide enough value to warrant continuation, the UDWR will consult with the Department of Natural Resources ESMF Office and the Utah 3-Species conservation team to determine appropriate and available long-term funding sources for annual operations.

02/01/2022

03/31/2022

2022

No work completed in FY 2022 (with FY 2021 carryover funds) related to the actual project proposal. However, we did complete structural modifications to allow us to proceed with future operation to gather the necessary data to allow us to evaluate fish passage at the Myton Diversion (see Project Narrative below).

Operation of the Myton Diversion fish passage structure is a long-term project (constructed in 2015) that has been funded through ESMF above-the-block grants for several years. Our ultimate goal is to provide the best information possible to evaluate success of this fish passage structure. In short, we need to provide data during flow scenarios that are advantageous for native fish spawning runs and recruitment success. In 2019, the Duchesne River had more than adequate high spring flows to gather the data we needed to assess passage when it matters. However, additional modifications were necessary to operate the facility in a safe manner under high flow conditions (i.e., very deep water, impossible to sample fishes) and these were not complete at that time. Working with the Ute Indian Tribe in FY 2022, we completed the necessary modifications to the structure to allow us to operate at any depth (i.e., lifting trap system, rather than manual netting), but unfortunately the Duchesne River watershed had well below normal snowpack levels and spring flows were meager at best, Leading up to potential spring operations in 2023, we coordinated with Central Utah Water Conservancy District to follow flow predictions closely before we determined that it would not be in our best interest to operate the structure. Rather, it made more sense to make another funding request for future operation in hopes that environmental conditions are more beneficial.

We have submitted a new proposal (funded for FY2023) for spring operation of the fish passage structure. Beginning in January/February we will follow the same process to determine whether we operate the structure next spring with this funding. Once we do have a valid high water data point, we will discuss with ESMF personnel how to proceed with a multi-year report.