PROJECT BACKGROUND

Non-native fish species are impacting native salmonid populations throughout the Pend Oreille Subbasin. Competition, hybridization, and predation by non-native fish have been identified as primary factors in the decline of native Bull Trout (BT) and Westslope Cutthroat Trout (WCT) populations. Over 99% of tributaries to the Pend Oreille River were historically occupied by native WCT; now less than 35% hold WCT. Although anthropogenic impacts contributed to significant declines over the past century, corrections to those impacts (i.e., habitat modifications), in the presence of non-native fish tend to benefit invasive species instead of the focal species, which are native to the system. Therefore, the goal of this project is to implement actions to suppress or eradicate non-native fish in areas where native populations are declining or have been extirpated and reintroduce native fish species where appropriate. These projects have been identified as critical to recovering native ESA-listed BT and declining populations of WCT. Actions developed through this project have either direct impacts on non-native fish species (e.g., reduced numbers through suppression/eradication activities),  lead to actions in which non-native fish species are directly impacted (e.g., collect fish distribution data to warrant action; develop management strategies for non-native fish species; collect data on impacted native salmonid populations) or monitor the response to recovered native fish populations  following actions taken against non-native fish species. As such this project will discuss actions categorized into two types:

1. Mechanical Suppression: Physical removal of non-native fish species of interest by way of electrofishing, netting (gill, fyke, seine, etc.), trapping (weir, light-minnow, minnow, etc.) or angling leading to a depressed or reduced population.

2. Eradication: Removal of non-native fish species of interest by way of chemical piscicide (pesticide) application or other mechanical removal technique leading to an eradicated population in the target project area.

MECHANICAL SUPPRESSION AND MONITORING ACTIVITIES IN TRIBUTARIES

MILL CREEK (MILL SUBBASIN): Mill Creek historically contained a pure WCT population but now is comprised largely of EBT, although a genetically pure, low density WCT population remains. Resident (non-migratory) fish in Mill Creek are protected from further invasion of EBT by a natural migratory barrier low in the creek, within approximately one mile of its confluence with the Pend Oreille River; this barrier is likely passable by large migratory salmonids at least seasonally. In 2018, Mechanical suppression of EBT using electrofishing techniques will be implemented. Due to the size of the project area (barrier to headwaters), being >16 miles (>26 Km) in total, the project will be separated into two phases. Phase 1 will begin in 2018 and focus on the headwaters section above the confluence of Mill Creek and Sylvis Creek. Total project length of phase 1 is approximately 10.4 miles (16.8 Km). In 2019, Phase 2 will be implemented which will include the remainder of Mill Creek and tributaries from just below Sylvis Creek to the barrier; this will add an additional 5.8 miles (9.4 Km) to the project. Environmental DNA (eDNA) samples may be collected to assist in determining the distribution of both species present in the project area.

SAUCON CREEK (LECLERC SUBBASIN): Saucon Creek historically contained a pure WCT population and is now comprised of a mixed population of EBT and WCT. Saucon Creek is protected from further invasion of EBT by a barrier low in the creek near the confluence with West Branch LeClerc Creek. Mechanical suppression of EBT using electrofishing techniques was implemented in beginning in 2014 in the 2.1 Km section where sympatric populations of WCT and EBT exist; upstream of this point is a barrier in which allopatric WCT occupy the remaining upstream habitat. In total we have removed >3,100 EBT in Saucon Creek and project trends indicate EBT densities are significantly decreasing annually , with increasing WCT densities. In 2018, we will conduct an additional EBT removal treatment and anticipate similar project trends.

ERADICATION AND MONITORING ACTIVITIES IN TRIBUTARIES

The Kalispel Natural Resources Department (KNRD) and Washington Department of Fish and Wildlife (WDFW) are operating a closely coordinated program to plan and implement actions focused on removing non-native fish species from select tributaries in the Pend Oreille Basin and subsequently restoring genetically pure, native WCT. These actions, focused primarily on the use of piscicide to remove non-native fish species, are identified through Federal Energy Regulatory Commission (FERC) licenses issues recently to the Pend Oreille Public Utility District (PUD) for operations of Box Canyon Dam and Seattle City Light (SCL) for operations of Boundary Dam.

MONITORING WESTSLOPE CUTTHROAT TROUT POPULATION IN CEE CEE AH CREEK (CEE CEE AH SUBBASIN): A pilot piscicide treatment project conducted in Cee Cee Ah Creek provided the foundation for advancing this program to a planning and implementation phase. After a successful series of piscicide treatments (2008-2010), WCT were translocated in small numbers to the treatment area (2011-2012) and monitoring has indicated the population is successfully recruiting new age classes and expanding in the available habitat; population estimates indicate there are now >4,800 WCT in the Cee Cee Ah Creek project area.  WCT distribution monitoring (snorkeling), and non-native fish monitoring (eDNA sampling), and thermograph installation occurred in 2017. No additional monitoring activities are planned in 2018; however If time allows, we may collect several eDNA samples on 2018 to ensure no EBT have been re-introduced to the treatment area.

SMALLE CREEK PISCICIDE TREATMENT EFFECTIVENESS MONITORING (CALISPELL SUBBASIN): The upper reaches of Smalle Creek, above a natural barrier, were treated with piscicide in 2015, 2016, and 2017 to remove non-native EBT. Depending on eDNA sampling results a treatment may or may not occur again in 2018, with funding provided by the Pend Oreille PUD (PUD). Under this BPA contract, we have monitored the effectiveness of the 2015-17 treatments by collecting an eDNA sample every 250-300 m of the treatment area. This project may support supplemental eDNA sampling in 2018 if deemed appropriate or necessary (outside of the PUD sampling effort). The cumulative information will indicate if the project has successfully removed all EBT or if some individuals remain (and where) so we can target those areas in 2018. Once the project is deemed successful we will restore the WCT population and conduct monitoring protocols (2018-on)

MECHANICAL SUPPRESSION AND MONITORING ACTIVITIES IN MAINSTEM RIVERS OR LAKES

PEND OREILLE RIVER NORTHERN PIKE SUPPRESSION: Northern Pike (NP), illegally introduced in the Clark Fork River, Montana has immigrated to the Washington’s Pend Oreille River, where they have caused drastic declines in native species and gamefish being managed by State and Tribal agencies. Northern Pike threaten to undermine current and future recovery efforts for BT and WCT, as well as other native salmonids, minnows, suckers and introduced gamefish in the watershed. Northern Pike also pose significant risks to the anadromous fisheries of the Columbia River and Endangered Species Act (ESA) recovery efforts if left unchecked to emigrate further downstream.

After engaging the public in 2011-2012, KNRD and WDFW developed a 3-pronged approach to suppressing the Pend Oreille River Box Canyon Reservoir population to pre-2004 levels: increasing angler harvest through outreach and education, targeted (harvest-oriented) fishing contests, and mechanical suppression of the population with gillnets. The objective was initially to reduce the abundance of NP in Box Canyon Reservoir from the 2011 Spring Pike Index Netting (SPIN) survey catch-per-unit-effort (CPUE) value of 13.2 NP/net night in the southern half (core area from Pioneer Park to Riverbend including sloughs) to <1.73 NP/net night and from 1.9 NP/net night in the northern half (Riverbend to Box Canyon) to <0.5 NP/net night.

KNRD, with support from WDFW has implemented six years of mechanical suppression in BCR (2012-2017) with project support provided by BPA, US Bureau of Indian Affairs, WDFW, Kalispel Tribe, and Avista Corporation. Up to 35 specifically designed gillnets gill nets were deployed and retrieved daily, with target net saturation generally occurring from ice-off (March) through the spring freshet (June) or ended earlier if target reduction was met (2014) or later phases were unplanned (2015-on).

Thus far >17,000 NP were removed in >4,600 overnight gillnet sets in the Pend Oreille River. Based on 2017 SPIN results, the adult population in the core area (southern half of BCR and sloughs) was reduced by > 99% from the 2011 baseline of 13.2 NP/net to 0.06 NP/net night. Recreational angler harvest appeared negligible based on observations by field staff, derby results, and anecdotal reports and as anticipated, mechanical suppression removed the vast majority of NP. In 2015, a report on the effectiveness of mechanical suppression to remove 87% of the NP population was produced as a supplemental technical report to the 2015 Non-Native Fish Suppression (BPA Project No. 2007-149-00) annual report and submitted the Independent Scientific Review Panel of BPA’s Fish and Wildlife Program and is available to interested parties.

Although the BCR population is largely depressed, a 2016 SPIN survey in the downstream Boundary Reservoir indicated the NP relative abundance was higher than anticipated and warrants additional mechanical suppression. In the first year of monitoring the downstream Boundary Reservoir, the CPUE for sloughs was 5.44 NP/net night and 1.58 NP/net night in river sets, indicating suppression efforts needed to expand downstream to the upper section of this reservoir. In 2017 there were 303 Northern Pike removed in 146 nets during Boundary Reservoir suppression efforts. The SPIN Survey results of 0.0 NP/net night (river) and 0.93 NP/net night (sloughs) indicated the population had been reduced significantly from 2016, but still remained above the relative abundance target for the reservoir of <0.5 NP/net night.

Suppression will continue in 2018 for both reservoirs. Based on the 2018 Northern Pike suppression (March-April) and SPIN Survey (May) results for Box and Boundary reservoirs, the necessity and level of suppression will be developed for 2019. Staff from the Tribe and WDFW will meet annually and use all available data and information to make the appropriate decision on out-year suppression activities in both reservoirs.

CALISPELL LAKE AND CREEK NORTHERN PIKE SPIN SURVEY: Expansion and illegal mobilization of Northern Pike is a continual concern. In late 2017, anecdotal information of a new Northern Pike population in Calispell Lake and Calispell Creek was confirmed using eDNA sampling. Calispell Creek is a direct tributary to the Pend Oreille River in the Box Canyon Reservoir reach and terminates at its outlet on Kalispel Tribe Reservation land. Adding a potential uncontrolled source to the Pend Oreille River could undermine the progress of ongoing suppression efforts as well as posing significant risks to native fish species. Therefore it is critical evaluate the distribution and relative abundance of Northern Pike in the Calispell system. This will be assessed by monitoring the distribution, relative abundance (CPUE), and population structure with a SPIN survey in Calispell Lake and Calispell Creek. The proposed survey for Calispell Lake and Creek will use the same proven sampling techniques conducted in the Pend Oreille River annually from 2010-2017. Survey results will be shared with WDFW, at which point a management decision will be made regarding the population of Calispell Northern Pike.

As demonstrated in the Calispell system and other project areas, the advent of eDNA sampling technology greatly improved our ability to detect invasive fish species and quickly understand their distribution. As we move forward with non-native, invasive fish management and prevention, we will continue to apply proven and novel techniques as appropriate. In 2018, we will continue to use eDNA sampling as suppression and eradication projects in tributaries and larger bodies of water are investigated, developed, implemented, or monitored.

LAKE TROUT SUPPRESSION IN UPPER PRIEST LAKE (IDAHO): The Idaho Department of Fish and Game (IDFG) has been suppressing lake trout in Upper Priest Lake (UPL) through extensive gill netting since 1997.  A larger effort has been annually implemented since 2007, with >30,000 Lake Trout (LKT) removed from 2007-2017. Bull Trout redds are annually monitored in the UPL watershed and have increased from 7 (2007) to 91 (2017).

The Hickey Brothers Research (LLC) will again be contracted to use gillnets to remove LKT from UPL using their 36 foot commercial gillnet boat. Gillnets will be fished over a 7 day period in late May/early June 2018. Nets will be oriented based on catch rates at a particular site and on the discretion of the netting crew; effort will be made to avoid incidental BT captures by avoiding known concentrations. Data from the 2018 effort will be summarized and compared to previous years’ efforts to monitor the effectiveness and success of the project. This BPA project provides cost-share funding to continue LKT suppression and gill net repair and replacement.  The US Fish and Wildlife Service also contribute significant annual funding to the project.Continuing to reduce LKT predation and competition with BT and WCT through reduction and/or eradication efforts will assist in BT recovery and long term persistence of other native fish in UPL.

INVASIVE SPECIES COORDINATION AND PROJECT RESULTS SHARING

Given the scope of this project and the nearly two decades of invasive species management by KNRD, it is becoming more critical to be involved with the coordination of invasive species management and information sharing. In 2018 KNRD, through this BPA project and other programs, will continue to support attendance and presentation of invasive species management project data at local and regional conferences. This project will also support staff attendance at many local and regional coordination and technical staff meetings focused on addressing invasive species. The focal area is the Columbia River Watershed but other opportunities to address broader invasive species issues will be considered and attended as appropriate.