For FY 2024, 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. In October, 2022, a rotenone treatment was completed to eradicate the non-native species in the Slickrock Saddle Bench Spring and its outflow. A follow-up treatment is planned for Spring 2023. Continued monitoring of this spring and the adjacent Escalante River is necessary to evaluate the effectiveness of the treatments and monitor continued non-native threats.

Objective 1: Tri-annual distribution monitoring, removal and escapement evaluation of non-native fish species in the Escalante River Basin. Task 1: Remove non-native fish from stream in Slickrock Saddle Bench Spring. a: Continue tri-annual (spring, summer, and fall) mechanical sampling efforts in Slickrock Saddle Bench Spring to determine distribution and abundance of non-native fish populations. b: 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. c: Modify and adapt non-native eradication plan, as necessary. d: Complete field reports, data analysis and management, and summary reports.

Monitoring and removal of nonnative fish in the Escalante River and this tributary will help managers to understand the risk to the native Escalante River fish and how to mitigate this threat.

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. Utah Wildlife Action Plan (Utah Wildlife Action Plan Joint Team 2015) The goal of the Wildlife Action Plan is "to manage native wildlife species and their habitats, sufficient to prevent additional listings under the Endangered Species Act." Removal of non-native species that compete with and prey on the native fish species addresses threats outlined in the Wildlife Action Plan.

Not applicable.

Not applicable.

These activities are conducted under authority of the Utah Division of Wildlife Resources to manage wildlife populations.

Sampling efforts 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.

UDWR established 13 long-term monitoring stations (U4-L9) in the Escalante River in 2009. These stations are sampled biennially and are adjacent to the project location. Routine monitoring will help determine if this project is successful.

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 and 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. UDWR will continue to evaluate threats posed by nonnative fish species to three species populations and evaluate triggers for control or eradication projects.

Not applicable.

07/01/2023

06/30/2024

2024

Non-native fish eradication in Slickrock Saddle Bench Spring in the Escalante River Basin was performed using mechanical and chemical removal methodologies outlined below: Mechanical removal: Sampling was conducted by a five-person field crew. All available habitat within the spring and stream was sampled using a knotless nylon seine (1.2 x 4.6 m, 3.2 mm mesh) and hoop nets (1.5 x 0.61 m, 6.5 mm mesh). Seine hauls were pulled in all available habitat. Hoop nets were set in any areas where seining was ineffective (i.e., deep and wide). Hoop nets were set overnight and average depth (ft) was recorded at time of set. All fish captured were identified to species and measured to the nearest 1.0 mm (total length) or enumerated into age classes based on size (adult, juvenile, and young); all non-native fish captured were removed and euthanized. Catch per effort (CPE) was calculated for both sampling methods. For seining, CPE was calculated by dividing the total number of fish captured by the total number of seine hauls. For hoop nets, CPE was calculated by dividing the total number of fish captured by the total number of trap hours for each hoop net. Air and water temperatures were recorded at the beginning and end of sampling. Chemical treatment: Pre-Treatment Prior to the rotenone treatment, beaver dams were notched 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, a secondary pour off pool, and all stream habitat, to treat at a concentration of 4 parts per million (ppm). Liquid rotenone (Chem Fish Regular 5%) and Cat litter (Fresh Step Crystals Silica) was mixed at a formulation of 1 L of cat litter to 100 ml of liquid rotenone (10:1) to cover an area of 5 m2. The mixture formed slow release capsules that were hand spread and dropped to the bottom of the spring fed pool and deep runs. Liquid rotenone was also used in a micro-drip to treat a seep inflow at the edge of the spring fed pool and in backpack sprayers to treat the shallow marsh habitat and isolated pools downstream of the beaver dam complex. The treatment was conducted under Utah Department of Agriculture and Food non-commercial applicator license number 4002-15584. Non-native escapement and distribution sampling in the Escalante River near the outflow of Slickrock Saddle Bench Spring was completed using a knotless nylon seine (1.2 x 4.6 m, 3.2 mm mesh). All available habitat was sampled approximately 600 m upstream and downstream of the outflow of Slickrock Saddle Bench Spring.

In FY23, a rotenone treatment was conducted in Slickrock Saddle Bench Spring to eradicate non-native fish species that threaten native fish populations in the Escalante River. Post- treatment efficacy sampling in late FY23 resulted in the capture of two non-native fish species including Green Sunfish (n=7) and Black Bullhead (n=12), indicating additional non-native fish eradication activities were warranted. In FY24, non-native fish eradication activities were conducted in the Escalante River Basin and included multiple rotenone treatments and post-treatment efficacy sampling in Slickrock Saddle Bench Spring along with non-native fish escapement/distribution sampling in the Escalante River mainstem. Results of non-native eradication efforts are summarized by activity, month, and year below: Rotenone treatments August 2023 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 4 ppm . Liquid rotenone added to kitty litter was used in the main pool and other deep pools and totaled 19 ounces. Liquid rotenone used in a micro-drip to treat a seep in the main pool totaled 4 ounces. Liquid rotenone usage in the shallow marsh habitat and isolated pools downstream of the beaver dam complex totaled 24 ounces. 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. October 2023 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 4 ppm (Table 1). Liquid rotenone added to kitty litter was used in the main pool and other deep pools and totaled 24 ounces. Liquid rotenone usage in the shallow marsh habitat and isolated pools downstream of the beaver dam complex totaled 48 ounces. 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 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. Post-treatment Efficacy Sampling October 2023 A total of 10 seine hauls were pulled in Slickrock Saddle Bench Spring to detect the presence of non-native fish species. No fish were captured or observed during sampling efforts. May 2024 Seining A total of 21 seine hauls were pulled in Slickrock Saddle Bench Spring yielding no fish captured or observed. Hoop Nets A total of eight hoop nets were set in Slickrock Saddle Bench Spring yielding no fish captures. Hoop net total soak time was 162.77 hours. Non-native Fish Escapement/distribution Sampling in the Escalante River May 2024 A total of 79 seine hauls were pulled in the Escalante River Mainstem, upstream and downstream of the Slickrock Saddle Bench Spring outflow. No non-native fish species were captured during sampling efforts. Native fish species captured included Flannelmouth Sucker (n=69; range 62-399 mm TL), Bluehead Sucker (n=34; range 52-227 mm), and Speckled Dace (n=57; range 44-111 mm). Overall, treatment efforts in Slickrock Saddle Bench Spring were successful in achieving non-native fish eradication in FY24. It was encouraging that no living fish were observed post-treatment in August and October 2023 and during post treatment efficacy sampling in May 2024.

It is recommended that continued monitoring be implemented in Slickrock Saddle Bench Spring to confirm treatment efforts remain successful and to allow the early detection of any recolonization of non-native fish that would threaten intact native fish populations in the Escalante River.