Project Details

Fish within the Esocidae family are among the most sought after freshwater sportfish in North America and are widely viewed as a premier trophy fish. Tiger Muskellunge (Esox masquinongy x E. Lucius), a sterile, hybrid fish produced by crossing Muskellunge (Esox masquinongy) and Northern Pike (Esox lucius), is a particularly fast-growing esocid because no energy is spent on reproduction. Tiger Muskellunge provide a unique opportunity for natural resource managers to create trophy fishing opportunities without the risk of establishing an unwanted naturally reproducing population while simultaneously taking advantage of their piscivorous nature to control nuisance or overabundant fish populations. However, because of their solitary and sedentary behavior, Tiger Muskellunge are a difficult species to manage. Traditional fishery monitoring techniques estimate population abundance and demographics as a snapshot in time and space and rely on large sample sizes. The combination of low capture rates and spatial segregation typically found with Tiger Muskellunge limits fishery-independent data and can restrict the ability of managers to make informed management decisions.

Acoustic telemetry has gained widespread popularity as a tool to understand migration, habitat use, and survival of aquatic animals. Acoustic telemetry functions similarly to radiotelemetry in terrestrial environments; an animal-borne tag transmits an acoustic signal detected by a receiver, which in this case is an underwater hydrophone. Compared to capture-recapture studies where numerous animals are tagged in hopes that a small proportion of tagged individuals are observed later, acoustic telemetry provides an abundant and continuous stream of detection data and spatial movements across multiple years without the need for recapture. Furthermore, once an array of acoustic telemetry receivers is deployed, multiple studies can be conducted on various species to rapidly increase the number and quality of inferences the researcher can extract from the detection data. Acoustic telemetry is a powerful tool to gather fine- and broad-scale data on fish movement, habitat requirements, and responses to environmental change. Improving population estimates and understanding behavioral traits are important for ecosystem-based management in aquatic environments and can help managers better understand how species respond to environmental changes (e.g., seasonal drawdowns and habitat loss), intraspecific competition (e.g., resources and space), predator-prey dynamics, and refine population size estimates to inform stocking strategies.

Pineview Reservoir, Weber County, Utah is a popular warm-water fishery that experiences significant seasonal drawdowns. The Tiger Muskellunge population at Pineview Reservoir is considered a trophy fishery; however, monitoring of Tiger Muskellunge is not conducted regularly because of the difficulty associated with sampling, and angler catch rates and satisfaction are declining. Tiger Muskellunge at Pineview Reservoir has traditionally been stocked at a high density of 50-mm fingerlings. Recent drought years have reduced the availability of nearshore nursery habitats and may have limited the survival of fingerling Tiger Muskellunge. UDWR managers are developing an adaptive stocking model to adjust the size-at-stocking (50 vs 200-mm fish), stocking frequency, and time of stocking (spring vs summer) by accounting for key physical and biological attributes limiting the growth and recruitment of juvenile Tiger Muskellunge. However, the behavior, habitat use, intraspecific competition among age-classes, and mortality of Tiger Muskellunge are not known.

Additionally, part of this project will be to add more habitat to promote the recruitment of young of the year (YOY), age 1, and adult Yellow Perch, Perca flavescens, Black Crappie, Pomoxis nigromaculatus into Pineview Reservoir.  Dramatic fluctuations in reservoir levels and fall turnover create situations that make survival very low for YOY, age 1, and adult fish.  This additional habitat will increase the probability for these fish to overwinter and stabilize the panfish population in the reservoir.

Provide evidence about the nature of the problem and the need to address it. Identify the significance of the problem using a variety of data sources. For example, if a habitat restoration project is being proposed to benefit greater sage-grouse, describe the existing plant community characteristics that limit habitat value for greater sage-grouse and identify the changes needed for habitat improvement.

Provide an overall goal for the project and then provide clear, specific and measurable objectives (outcomes) to be accomplished by the proposed actions. If possible, tie to one or more of the public benefits UWRI is providing.

Pineview Reservoir is an impoundment of the Ogden River with a surface area of 11.6 km2, a normal operating depth of 25.0 m, and a mean depth of 13.4 m. The primary fish community is comprised of black bullhead (Ameiurus melas), black crappie (Pomoxis nigromaculatus), bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), smallmouth bass (M. dolomieu), tiger muskellunge, and yellow perch (Perca flavescens). Fish community sampling occurs on a two-year rotation and Tiger Muskellunge are stocked on an annual basis.

Pineview Reservoir consists of three inlet forks and one outlet fork, with each inlet fork physically isolated by peninsulas from the others and all forks converging in the center of the reservoir (see attached map). The reservoir shape is ideal for acoustic telemetry studies as the geographical barriers between reservoir forks prevent individuals from being detected in multiple forks and allows for broad-scale spatial and seasonal movements to be monitored with a limited number of receivers. An acoustic array within each fork would allow researchers to quantify habitat use, spatial overlap of conspecifics, and seasonal migration behaviors. The morphology of the outlet fork is steep with limited shoreline habitat; therefore, we propose to not deploy receivers in this fork of the reservoir as suitable habitat for juvenile Tiger Muskellunge is not present.

Recent drought conditions have greatly reduced water volumes among reservoirs within the Weber River drainage. Pineview Reservoir dropped to levels not seen in over two decades.  High summer water temperatures and low water levels have eliminated shoreline habitats and nursery grounds typically accessed by Yellow Perch, Black Crappie, and Tiger Muskellunge. During seasonal drawdowns, deep-water, artificial habitats can provide invaluable resources for escaping predation and increasing survival in the forage fish community. UDWR has been installing artificial habitat structures within Pineview Reservoir since 2018, has observed the success in forage fish survival, and sees the need to include more in the reservoir.

LOCATION: Justify the proposed location of this project over other areas, include publicly scrutinized planning/recovery documents that list this area as a priority, remote sensing modeling that show this area is a good candidate for restoration, wildlife migration information and other data that help justify this project's location.

TIMING: Justify why this project should be implemented at this time. For example, Is the project area at risk of crossing an ecological or other threshold wherein future restoration would become more difficult, cost prohibitive, or even impossible.

The following objectives are found in the Utah Tiger Muskellunge Management Plan:
1. Objective A.6, C.6.G - Maintain and improve the quality of stocked and wild fish populations in Utah.
This objective will be addressed by identifying post-stocking survival rates and population dynamics of juvenile Tiger Muskellunge to inform optimal stocking densities and stocking strategies (i.e., size-at-stocking, stocking frequency). Additionally, we can improve the robustness and precision of ongoing capture-recapture studies to greatly improve the quantitative methods for assessing Tiger Muskellunge stocks.

2. Objective C.6, R.2.F - Establish quantifiable desired habitat conditions and develop standardized habitat monitoring procedures. Apply these procedures to establish baseline habitat conditions before restoration work and repeat these assessments after work is completed so success can be evaluated. Adapt management approaches based on monitoring conditions.  
This objective will be addressed by linking juvenile Tiger Muskellunge presence to specific physical and habitat components to guide habitat development plans and ensure suitable nursery habitat is present as reservoir levels fluctuate. Additionally, by incorporating adult Tiger Muskellunge we can identify critical habitat use across life stages.

These next plans are from working documents in regional work plan efforts. Constituency goal: C.6 -- Increase hunting and fishing opportunities. Improved access and additional fishing opportunities for anglers
Increased participation in fishing within the Northern Region. Reduce habitat fragmentation and reconnect fish populations

F-Perform 5 habitat improvement projects annually to increase fishing access , habitat quality and sustainability

Increased fishing success for anglers
Improved watershed, ecosystem and stream health
Improved fish populations in systems where habitat is limiting
Maintain and strengthen relationships with private landowners, Trout Unlimited, NRCS, DWQ and other key partners

R.2 -- Maintain existing wildlife habitat and increase the quality of critical habitats and watersheds throughout the state
Improved fish populations in systems where habitat is limiting
Maintain and strengthen relationships with private landowners, Trout Unlimited, NRCS, DWQ and other key partners
Leverage ability to get work done through those relationships

List management plans where this project will address an objective or strategy in the plan. Describe how the project area overlaps the objective or strategy in the plan and the relevance of the project to the successful implementation of those plans. It is best to provide this information in a list format with the description immediately following the plan objective or strategy.

If applicable, detail how the proposed project will significantly reduce the risk of fuel loading and/or continuity of hazardous fuels including the use of fire-wise species in re-seeding operations. Describe the value of any features being protected by reducing the risk of fire. Values may include; communities at risk, permanent infrastructure, municipal watersheds, campgrounds, critical wildlife habitat, etc. Include the size of the area where fuels are being reduced and the distance from the feature(s) at risk.

Describe how the project has the potential to improve water quality and/or increase water quantity, both over the short and long term. Address run-off, erosion, soil infiltration, and flooding, if applicable.

Description of efforts, both completed and planned, to bring the proposed action into compliance with any and all cultural resource, NEPA, ESA, etc. requirements. If compliance is not required enter "not applicable" and explain why not it is not required.

We propose to deploy acoustic arrays, one within each outlet reservoir fork, for a total of 12 receivers (Innovasea NexTrak R1) systematically placed throughout the reservoir. Receivers will be suspended 2 m from the bottom of the reservoir with a 50-m snag line stretched along the bottom of the reservoir for retrieval. A temperature logger will be attached to each receiver. Receivers will need to be serviced (i.e., battery change, data download) annually.

Tiger Muskellunge are produced annually by the UDWR and raised in a hatchery setting up to 200 mm in length prior to stocking. We propose to tag 75 juvenile Tiger Muskellunge (150-200 mm total length) prior to stocking with one of the smallest commercially available acoustic transmitters (Innovasea V8-4x; 8 mm diameter; 20.5 mm length; 2.0 in air; >400-d tag life) to increase post-stocking survival. Individuals will be selected haphazardly from their rearing tank. Each fish will be measured, sexed, and tagged with an intramuscular external tag located near the posterior edge of the dorsal fin. Fish will be anesthetized (Aqui-S 20E), placed supine on a surgical board for tag implantation, and incisions closed with a synthetic absorbable monofilament. Tagged juveniles will be monitored for 1-week in a hatchery raceway, accessed for incision healing, inflammation, and tag retention, and then transported and dispersed throughout the reservoir. Additionally, we propose to tag 20 adult Tiger Muskellunge collected by the Utah Division of Wildlife Resources via boat electrofishing and local Muskies, Inc. chapter members captured by hook and line. Adult Tiger Muskellunge will be tagged with a larger acoustic transmitter (Innovasea V13-1x; 13 mm diameter; 31.5 mm length; 9.4 in air; >1800-d tag life) to increase tag life and study duration. Tagged adults will be held in an aerated tank until individuals are recovered. All field tagging events will be conducted when water temperatures are below 20C to facilitate incision healing and minimize infection. All surgeries will be conducted by a single trained researcher.

Once habitats are received and transported to the reservoir, groups and individuals will assemble these habitats.  Assembled habitats will be transported to a designated area marked by a minimum of four buoys.  Larger habitats (i.e. Mossback) will be placed in the center and smaller habitats (i.e. Pond King) will surround them.  These habitats will be randomly spread throughout the designated drop area.  This area will be at a depth which still had plenty of water in 2021 during the lowest reservoir elevation levels seen in the past 20 years.

Describe the actions, activities, tasks to be implemented as part of the proposed project; how these activities will be carried out, equipment to be used, when, and by whom.

Protocols for intracoelomic tag implantation will be evaluated based on the survival, degree of healing, and tag retention rate after the 7-day hatchery holding period. Individuals that do not meet criteria for release will be euthanized and tags will be removed and deactivated for future use. Additionally, the intramuscular external tag will allow for long-term incision healing and the condition of tagged fish to be monitored during angler captures.

Detection data will be downloaded from the receivers annually. Post-stocking survival will be evaluated as the proportion of individuals surviving through the first growing season. Individuals will be assumed to be alive until one of the following events is observed and considered to be a mortality: (1) the total cessation of detections after clear evidence of movement; (2) the beginning of a gap in detection history spanning at least 4 months, with no clear evidence of movement; or (3) the beginning of a long string of detections at one or very few adjacent receivers (e.g., 3 months) as a dead fish or a tag resting on the bottom near the receivers), with no subsequent evidence of movement.

A set of linear mixed-effect models will be used to quantify seasonal and inter-annual changes in detections within and among the reservoir forks. Daily presence/absence at each receiver will be analyzed as a binomial response variable, sex and tagging location or release location as fixed effects, and total length at tagging, age of fish, water temperature, monitoring year, and day of year as random effects.

A movement matrix will also be used to quantify the degree of connectivity between receivers and regions of the reservoir. This matrix will be used to create weighted and directed seasonal networks for each tagged individual that reflects the extent of space and habitat used during the entire monitoring period and the relative importance of each habitat occupied.

Habitat use by above mentioned fishes, will be conducted during the fall and winter months via boat using sonar to graph habitats and fish.  During the winter, sonar used for ice fishing purposes will also be used to detect fish using the structures.  An ROV may also be used during these times to capture live video of the structures and any fish around them.

Describe plans to monitor for project success and achievement of stated objectives. Include details on type of monitoring (vegetation, wildlife, etc.), schedule, assignments and how the results of these monitoring efforts will be reported and/or uploaded to this project page. If needed, upload detailed plans in the "attachments" section.

List any and all partners (agencies, organizations, NGO's, private landowners) that support the proposal and/or have been contacted and included in the planning and design of the proposed project. Describe efforts to gather input and include these agencies, landowners, permitees, sportsman groups, researchers, etc. that may be interested/affected by the proposed project. Partners do not have to provide funding or in-kind services to a project to be listed.

Detail future methods or techniques (including administrative actions) that will be implemented to help in accomplishing the stated objectives and to insure the long term success/stability of the proposed project. This may include: post-treatment grazing rest and/or management plans/changes, wildlife herd/species management plan changes, ranch plans, conservation easements or other permanent protection plans, resource management plans, forest plans, etc.

Potential for the proposed action to improve quality or quantity of sustainable uses such as grazing, timber harvest, biomass utilization, recreation, etc. Grazing improvements may include actions to improve forage availability and/or distribution of livestock.