For FY 2023, UDWR proposes non-native fish monitoring and eradication in Slickrock Saddle Bench Spring and the Escalante River to benefit Roundtail Chub, Flannelmouth Sucker and Bluehead Sucker populations. The Range Wide Conservation Agreement and Strategy for Roundtail Chub, Bluehead Sucker and Roundtail Chub (Three Species), signed by Utah Division of Wildlife Resources (UDWR) and other stakeholders, lists as a conservation action the control (as feasible and where possible) of threats posed by nonnative species that compete with, prey upon, or hybridize with the three species (UDWR 2006). The Escalante River Basin in south central Utah contains several species of non-native fish including Red Shiner (Cyprinella lutrensis), Green Sunfish (Lepomis cyanellus), Fathead Minnow (Pimephales promelas), Black Bullhead (Ameiurus melas), Striped Bass (Morone saxatilis), Common Carp (Cyprinus carpio), Channel Catfish (Ictalurus punctatus), and Gizzard Shad (Dorosoma cepedianum) (Holden and Irvine 1975; McAda et al. 1977; Mueller et al. 1999; Hepworth et al. 2001; Morvilius and Fridell 2005). In tributary streams of the upper Escalante River Basin, UDWR has stocked several species of trout including Rainbow Trout (Oncorhynchus mykiss), Brown Trout (Salmo trutta), non-native Cutthroat Trout (Oncorhynchus clarkii ), and Brook Trout (Salvelinus fontinalis). In 2017, Green Sunfish were captured in Mamie Creek during Three Species distribution sampling conducted in the Escalante River and tributaries by UDWR. Based on this finding, the Bureau of Land Management (BLM) suggested that the source population of Green Sunfish was from an off-channel area within the Grand Staircase-Escalante National Monument. In 2018, sampling efforts in Slickrock Saddle Bench Spring, a tributary to the Escalante River, confirmed the presence of a suite of non-native species including Green Sunfish, Black Bullhead, and Fathead Minnow. This spring and associated stream has no official name; for reporting purposes it is referred to as "Slickrock Saddle Bench Spring" due to the nearest upstream feature (Slickrock Saddle Bench). Since 2018, mechanical removal efforts by seining and hoop net trapping have resulted in the capture of Green Sunfish (n=1,308), Black Bullhead (n=488), and Fathead Minnow (n=3,570) which consisted of multiple age classes of each species. Results of sampling in 2021 have indicted a decrease in relative abundance of all three non-native species compared to 2018 when sampling efforts were initiated. However, complete eradication through mechanical removal has not been achieved. In concert with mechanical removal efforts in Slickrock Saddle Bench Spring, UDWR has conducted non-native escapement evaluation sampling in the Escalante River. Sampling consists of seining all available habitat approximately 800 m upstream to 500 m downstream of the confluence with Slickrock Saddle Bench Spring. Sampling in 2019 resulted in the capture of 10 Fathead Minnow that likely escaped the off-channel stream during periods of connectivity from high flows during monsoonal rain events. Following the capture of Fathead Minnow in 2019, there have been no further captures of non-native species in the Escalante River that are present in Slickrock Saddle Bench Spring.

1) Conduct (summer) mechanical sampling efforts in Slickrock Saddle Bench Spring, pre-rotenone treatment, to determine distribution and abundance of non-native fish populations. Sampling will be conducted using a 4.6 x 1.2 m (3.2 mm mesh) knotless nylon seine and hoop nets measuring 1.5 x 0.61 m (6.5 mm mesh). All non-native fish captured will be removed. 2) Continue escapement evaluation sampling in the Escalante River upstream and downstream of the confluence with Slickrock Saddle Bench Spring to detect the presence of non-native fish species from off channel populations. All available habitat will be sampled using a 4.6 x 1.2 m (3.2 mm mesh) knotless nylon seine. 3) Develop a plan for successful eradication of non-native fish through inventory, removal, and chemical treatments. 4) Coordinate preliminary planning efforts with UDWR and BLM to ensure proper permitting and regulatory processes are completed, as necessary, prior to a potential chemical treatment within the GSENM. 5) Conduct periodic aquatic habitat monitoring in the off channel stream prior to proposed chemical treatment to include streamflow (cfs), water depth and volume, water temperature, pH, dissolved oxygen, and seep/inflow mapping. 6) Conduct two rotenone treatments of Slickrock Saddle Bench Spring to eradicate non-native fish species. Rotenone treatments will be conducted in late summer, post monsoon season, and during targeted periods of drying with no connection from the off-channel stream to the mainstem Escalante River. 7) Conduct post-rotenone treatment sampling to access the efficacy of treatment efforts. 8) Modify and adapt non-native eradication plan, as necessary. 9) Complete field reports, data analysis and management, and summary reports.

The primary concern is the loss of native fish in the Escalante River. SRO native aquatic personnel have vast experience at conducting chemical treatments and ensuring all treated water is properly detoxified and no non-target species or areas are at risk. Rotenone treatments will be conducted during periods of non-connectivity of Slickrock Saddle Bench Spring to the mainstem Escalante River. Risks to personnel from chemical exposure are addressed by requiring Utah pesticide applicator certification and safety training.

Conservation and Management Plan for Three Fish Species in Utah: Addressing needs for Roundtail Chub (Gila robusta), Bluehead Sucker (Catostomus discobollus), and Flannelmouth Sucker (Catostomus latipinnis) (Andersen et al. 2006) The Conservation and Management Plan for Three Fish Species includes conservation actions to conserve these fish species that are addressed within this project proposal. These include: 1) Conduct status assessment of Roundtail Chub, Bluehead Sucker, and Flannelmouth Sucker. 3) Determine Roundtail Chub, Bluehead Sucker, and Flannelmouth Sucker population demographics, life history, habitat requirements, and conservation needs. 5) Increase Roundtail Chub, Bluehead Sucker, and Flannelmouth Sucker populations to accelerate progress toward attaining population objectives for respective species. 7) 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. The Utah Wildlife Action Plan (Utah Wildlife Action Plan Joint Team 2015) was developed to list potential threats to habitats and native species of Utah to prevent listing under the Endangered Species Act. Threats identified in the UWAP that directly affect the persistence of Three Species in the Southern Region include: Invasive Non-native / Alien Species (8.1).

Not applicable.

Rotenone treatments will be conducted during periods of non-connectivity of Slickrock Saddle Bench Spring to the mainstem Escalante River. Rotenone will naturally degrade over time in the treated area.

These activities are conducted under the authority of the Utah Division of Wildlife Resources to manage wildlife populations. The Bureau of Land Management is a cooperating agency, and will complete necessary regulatory compliance.

Multiple methods are implemented to control non-native fish in Slickrock Saddle Bench Spring. Currently, hoop nets and seines are used to capture and remove as many fish as possible from the off channel stream. In the Escalante River, seines are used to capture and remove non-native fish that may have escaped from Slickrock Saddle Bench Spring. In Slickrock Saddle Bench Spring, multiple rotenone treatments will be conducted to eradicate non-native fish during targeted periods of drying when the off-channel stream is not connected to the Escalante River.

UDWR established long-term monitoring stations (U4-L9) in the Escalante River in 2009 to evaluate longterm population trends in the Escalante River. Following rotenone treatments sampling will be conducted in Slickrock Saddle Bench Spring to evaluate the efficacy of treatment efforts.

Partners include those institutions and agencies involved with signatories to the Three Species Conservation Agreement and Strategy, as well as the Escalante River Watershed Partnership, particularly the Bureau of Land Management (Grand Staircase-Escalante National Monument).

UDWR will continue to manage Roundtail Chub, Flannelmouth Sucker, and Bluehead Sucker as outlined and recommended within the Conservation and Management Plan.

Not applicable.

07/01/2022

06/30/2023

2023

Pre-Treatment Prior to the rotenone treatment, all aquatic habitat in the off-channel stream was measured using hand-held meter tapes, range finders, and depth sticks, to determine the total volume of water in acre feet. Water temperatures (°C) were recorded throughout the off-channel site. Beaver dams were notched 24-hours prior to the treatment to lower water levels and encourage non-native fish to congregate. A block net was set downstream of the lowest notched beaver dam using a 1.2 x 4.6 m knotless nylon seine (3.2 mm mesh) to ensure non-native fish could not escape Slickrock Saddle Bench Spring into the Escalante River. Informational signs were posted in the treatment area at all access points and were removed once treatment activities ended. Treatment Rotenone powder (Prentox® 7.4%) was mixed with water to form a slurry, then diluted and distributed in proportion to volume across the main spring fed pool, secondary pour off pool, and all stream habitat, to treat at a concentration of 3 parts per million (ppm). Some solid rotenone powder was mixed with gelatin and sand to form slow release capsules that were dropped to the bottom of the spring fed pool. Liquid rotenone (Chem Fish Regular 5%) was sprayed with a backpack sprayer to treat the shallow marsh habitat and isolated pools downstream of the beaver dam complex to where flow subsided near the confluence with the Escalante River. The treatment was conducted under Utah Department of Agriculture and Food non-commercial applicator license number 4002-15584.

Slickrock Saddle Bench Spring was calculated to contain 0.93 acre-feet of water and was treated with 6.95 lbs of rotenone to reach a concentration of 3 ppm. Liquid rotenone usage in the shallow marsh habitat and isolated pools totaled 20 oz (Table 1). As required by the Bureau of Land Management, Slickrock Saddle Bench Spring was not connected or flowing into the Escalante River during the time of the treatment, therefore no detoxification was necessary. Speckled Dace (Rhinichthys osculus) were used as sentinel fish and were placed in wire-mesh minnow traps (42.5 cm long x 23.0 cm wide; openings were wired shut to prevent escape) downstream of the outflow of Slickrock Saddle Bench Spring in two locations in the Escalante River. Sentinel fish were checked every hour and remained alive during the treatment. Treatment efforts in Slickrock Saddle Bench Spring were successful in achieving target rotenone concentrations of 3 ppm to eradicate non-native fish. Observations of behavioral change in fish were first documented at 5.0 hours post-rotenone application, with Fathead Minnow gaping at the surface of the water and losing equilibrium. The first observation of fish mortality occurred at 5.3 hours post-rotenone application with dead Fathead Minnow found in the main pool. At 6.0 hours post-rotenone application, fish were observed seeking refuge in seeps along canyon walls. Liquid rotenone was used to treat the seeps and disperse fish from the refugia sites. Green Sunfish and Black Bullhead remained alive 8.0 hours post-rotenone application but showed signs of distress as treatment activities subsided on October 21, 2022. On October 22, 2022, approximately 24.0 hours post-rotenone application, all observed Fathead Minnow and Green Sunfish were dead. In addition, approximately 10 Black Bullhead (adult and young age classes) were also found dead. Several adult Black Bullhead were found floating on the surface of the water still gaping and were removed by crews. It is likely that rotenone concentrations at 24.0 hours after initial application were still sufficient to kill any remaining fish.

To ensure 100% eradication, Slickrock Saddle Bench Spring will be treated again in 2023. Continued monitoring will be implemented in Slickrock Saddle Bench Spring to confirm treatment efforts were successful and allow for early detection of recolonization of non-native fish from the Escalante River.