Temple Fork of the Logan River is a source for a metapopulation of Bonneville Cutthroat Trout. Cutthroat trout use this tributary and Spawn Creek within this tributary to live year round and also to spawn each spring. Additionally, trout from the Logan River move into Temple Fork and Spawn Creek each spring to spawn and this results in the great importance of this tributary as a source of cutthroat trout within the tributary and also the river system as a whole. Utah State University has been conduction electrofishing surveys and population densities in Temple Fork since 2001, each year in late July or August. In 2017, they documented Brown Trout numbers were increasing and in 2018 the population had increased sevenfold. The project would be to install a picket weir and fish traps to temporarily trap both Bonneville Cutthroat and Brown Trout in the fall of 2019 to determine numbers and sizes of fish moving in and out of this system as the Brown Trout spawn in late fall.

1-Determine timelines of Brown Trout movements into Temple Fork and Spawn Creek in the Fall of 2019. 2- Determine the extent of distribution of Brown Trout throughout the system in Summer of 2019. 3- Determine whether adult Brown Trout are only moving into this tributary to spawn 4- Determine if a permanent barrier which could be operated in the spring to allow cutthroat trout an option to move into the tributary and block Brown Trout in the fall is necessary to protect this fishery.

The potentially largest threat to Temple Fork and the fishery may be the invasion of Brown Trout into the system and the increasing numbers of those fish. Although it has been documented throughout USU's surveys over the past 18 years, brown trout pose a considerable threat to cutthroat trout due to competition for food, spatially in habitat, and predation. It is believed that cutthroat can tolerate some brown trout in a system similar to Temple Fork but if numbers of brown trout continue to increase, cutthroat trout may decline.

Bonneville Cutthroat Trout is a species of great concern and in the Wildlife Action plan.

None

None

All permits and NEPA will be covered by the Forest Service

This fall a picket weir will be installed to trap fish moving into and out of Temple Fork at the confluence with the Logan River. PIT tags will be installed in all trapped brown and cutthroat trout to monitor movements within the river system and the Temple Fork and Spawn Creek systems. Additionally, population inventories will be taken in August prior to the weir installation.

We will monitor twice this summer and fall for brown trout in the system as well as the yearly survey conducted by USU. We will also continue to monitor movements of tagged fish in our trap and as other population estimates occur within the system.

Utah State University Trout Unlimited Forest Service Division of Wildlife Resources USGS

Upon completion of this project, the group will determine if a selective operational barrier needs to be installed, if mechanical removal of brown trout is needed, or possibly both to reduce numbers of brown trout within this tributary

This is a great source of a renewable resource. We greatly value this fishery and the species located within the system. We would greatly prefer to work with the fish we currently find and protect them instead of potentially having to chemically treat the system.

08/21/2019

04/30/2020

2020

The study area (Temple Fork tributary) was located 27.5 km upstream from the city of Logan UT, USA, on the Logan River (Wood 2008). The Logan River and its tributaries used by BCT were primarily located on United States Forest Service (USFS) property starting in Idaho and flowing into Utah within the Wasatch-Cache National Forest (Figure 1). The Logan River flows 86 km from Idaho South and West into the Bear River at Cutler Reservoir in Cache County, Utah. Temple Fork and its tributary, Spawn Creek, were an extremely important tributary to the Logan River for spawning native BCT. We identified 400m to 500m reaches of stream starting at the confluence of Temple Fork and Logan River. Reaches were marked with chartreuse flagging tape and labeled with the number of the reach and orientation (i.e. top or bottom) along with UTM waypoints. We separated and numbered each reach and the total numbers of captured and removed BNT and BKT were recorded. We imported the reach locations into GIS and constructed a density plot to show distribution of trout throughout the tributary with the densities of BNT and BKT in each reach in the system. This map of relative density provides a basis for understanding how Temple Fork was used by BNT and BKT. We started by conducting annual fish sampling in August 2019 in reference locations with USU. We measured all BNT and BCT by total length, weight, and location. We entered the data into a spreadsheet and saved as a .csv file to import into Program R. The following histograms, charts and graphs were part of the analysis of the data collected. Histograms allowed a quick assessment of the data based on the length of the fish and the number of each sized fish. We used the lengths of all fish collected and analyzed the data using length frequency histograms. Each crew sampled several reaches beginning with the lowest reaches and proceeding upstream. Where possible, reaches began and ended at an obvious marker, such as road, fence, trail crossing, or large beaver dam. This facilitated crews easily identifying the start or end of a reach. Each reach was electrofished using backpack electrofishing units. Electricity from a small 12 volt battery was transmitted into the water via Smith-Root 12A, 24, and 20 model backpack electrofishing units utilizing 150-300 V, 45-60 Hz, and 0.5-1.0 A based on similar research(Saunders et al. 2014). Fish within the effective field of electricity were temporarily stunned and catchable. Crews collected as many fish as possible in each reach. Crews of one biologist or an experienced technician led a crew of three to four more individuals. Each crew sampled a designated reach. We collected and identified fish to species. Brown Trout and BKT were removed from the population, length and weight was recorded and placed in a cooler on ice where they were cleaned, filleted, and dropped off to the local food pantry to be distributed. Cutthroat Trout were examined for an adipose fin clip. If the adipose fin was missing, the fish was placed in a bucket with water and length, weight, were recorded and then scanned for a Passive Integrated Transmitter (PIT) tag. All BCT were released into the reach where they were sampled. We evaluated the condition factor, Fulton's K, on the data collected by USU from 2010 to 2019 on BNT age classes 1 and 2 (Budy et al. 2008). The size limits for age 1 and 2 were 100 m to 179 mm and 180 mm to 259 mm. Based on our histograms our age 1 fish were 110 mm to 199 mm and the age 2 fish were 200 mm to 279 mm. Wood also discussed age 2 as fish over 200 mm (Wood 2008). We used the August removal effort data as a comparison since USU sampled in late July and early August in Temple Fork and Spawn Creek each year, if possible. We expected with an increase in BNT numbers the condition of BCT would have changed over time. We used the following equation for Fulton's K (Cerven 1973; Budy et al 2003): K = (W/L3) x 105 We stratified by age class, stream (Temple Fork or Spawn Creek), species, and year. Some years had fewer than 10 fish collected per age class or stream. We combined the years into three groups for each stream: early (2010 to 2012), mid (2013 to 2015) and late (2016, 2018 and 2019). Data was not collected in Temple Fork or Spawn Creek in 2017. Additionally, the picket weir (fish trap) was installed into Temple Fork on 23 September, approximately 90 meters upstream from the confluence of the Logan River and Temple Fork. A long shallow pool with a flat bottom was selected for installation and the location provided easy to access for installation, maintenance, checking, and removing. We placed two traps within the weir. One trap pointed upstream to capture fish leaving Temple Fork. The other faced downstream to capture fish entering Temple Fork to spawn. Brown Trout were not released and we did not capture any BCT. Documenting the quantities and timing of fish movement dictated the efficacy of either yearly mechanical removal of BNT and BKT or installing a barrier to prevent further expansion. We manned the weir by volunteers from Cache Anglers, TU, technicians, and USFS. Working with USU, we compiled historical BNT data for Temple Fork and attempted to determine if trends in abundance were associated with environmental or other biological factors. Prior to reach determination, we fished Temple Fork during July 2019 to determine the distribution of brown trout. During this trip we observed only BCT upstream of a large beaver dam. The top end of reach nine came from this evaluation. Fish collected during that trip were BCT and released. We designated nine reaches on Temple Fork and six reaches on Spawn Creek (Figure 4). Each removal effort reduced BNT and BKT numbers in the short-term and ensured BCT maintain Temple Fork as a population stronghold and source for new BCT recruits in the Logan River. The first removal effort for BNT and BKT occurred mid-August with the help of USU, UDWR, TU, USFS, and volunteers. The final removal effort concluded in mid-September after a weir was installed near the confluence of Temple Fork and Logan River. On 21 August, a large group of fisheries biologists, technicians, professors, and volunteers gathered at the main parking area for Temple Fork off U.S. Highway 89. We divided into three crews, each crew was assigned three reaches on Temple Fork and two reaches on Spawn Creek. Each crew sampled the lowest reach on Temple Fork the first morning, worked upstream and collected as many brown trout and cutthroat trout as possible. There were no BKT present in Temple Fork. The robust woody riparian vegetation increased the difficulty in collecting fish. Each crew kept all brown trout and only those cutthroat trout with a fin clip. All BCT were released during this collection effort. In addition to the removal efforts in August and September, spawning removals for BKT and BNT occurred in November on Spawn Creek and Temple Fork. This was an additional effort to reduce adult non-native fish and their progeny. We based our initial hike on professional knowledge and from data gathered (Beard 1991, Meredith 2012, Petty 2005). On 8 November 2019, we parked at the trailheads for both tributaries and hiked upstream looking for spawning fish on redds or spawning activity. We were unable to locate redds or spawning fish on Temple Fork and hiked to the top of reach 9. We hiked Spawn Creek and specifically looked at the small gravels where flows entered beaver ponds. This seemed like a suitable area to find spawning fish. We observed spawning BKT and BNT in reaches 4-6. We returned to Temple Fork on 14 November, for a removal effort.

We collected 3,117 non-native trout in Temple Fork and Spawn Creek in five days of intensive removal efforts. Brown Trout and Brook Trout were all killed and either cleaned, filleted, delivered to the local food pantry or taken to the predator research facility for USU. The removal of 3,100 + fish from these two small tributary streams will give Bonneville Cutthroat Trout an opportunity to spawn and recruit into the system. The fish trap from TU was used from September to December but we found that a mink may have been killing and removing trapped fish thus skewing our fish movement into Temple Fork. Future efforts may be warranted to see how many fish are moving into Temple Fork to spawn and thus adding to non-native trout numbers in Temple Fork.

The DWR will have to work with USU and make decisions for the future of this fishery. Overabundant populations of non-native trout in this tributary can impact the native trout. Options discussed in the capstone paper mention a decision to encourage the harvest of Brown Trout in the upper Logan River and tributaries. Another condition mentioned was to increase the limit of trout to be harvested to allow more to be harvested or allow an unlimited harvest on Brown Trout within the system. These changes may be received by the public very poorly so the DWR and USU would have to approach these options carefully.