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 (BTL) 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 BLT 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 ACTIVITIES ADDRESSING NON-NATIVE EASTERN BROOK TROUT IMPACTS IN TRIBUTARIES

GRAHAM CREEK (CALISPELL SUBBASIN): In an effort to conserve the remaining WCT in Graham Creek, in 2008, the KNRD installed a barrier structure just up from the mouth to eliminate future upstream migration of Eastern Brook Trout (EBT). A pre and post installation electrofishing effort was completed to remove all observed EBT between the fish passage barrier and a natural cascade/waterfall barrier 700 m upstream. In 2012, we conducted a single pass electrofishing survey to determine if any EBT remained in the treatment area; we collected 136 WCT (not including YOY fish) and 15 EBT. In 2013 we collected 182 WCT and only 1 EBT. Again in 2014 we collected 108 WCT and 1 EBT. In 2015 no EBT were observed in the project area.  It is necessary to conduct an additional removal treatment consisting of 1-2 passes using electrofishing gear in 2016 to confirm the absence of EBT. We will also collect eDNA samples to ensure no EBT are present.

WEST BRANCH LECLERC CREEK TRIBUTARY 1 (LECLERC SUBBASIN):To conserve a dwindling population of WCT, 2,148 EBT were removed from West Branch LeClerc Creek Tributary 1 (Trib 1) using standard backpack electrofishing treatments from 2003-2015.  Initially, EBT outnumbered WCT by a ratio of 3 to 1 in the project area located above a perched culvert near the confluence with West Branch LeClerc Creek.  The majority of early removal treatments consisted of multiple continuous single passes and although many EBT were removed using this method, we were concerned about potential harm to WCT electrofished in multiple treatments. In 2013 we modified the protocol to complete the removals in one treatment using multiple pass depletion techniques. This protocol continued in 2014 with no EBT captured for the first time in the eleven years of implementing the project and the highest recorded density of WCT to date (501 individuals captured).Again in 2015 no EBT were observed during the treatment.  Now that eradication appears to be successful, we will conduct one more single, continuous electrofishing treatment in 2016 to ensure no EBT remain. We will also collect eDNA samples to ensure no EBT remain.

SAUCON CREEK (LECLERC SUBBASIN): In 2013, a restoration project was developed and submitted to Washington's Salmon Recovery Funding Board (SRFB) in which multiple fish passage barrier culverts were to be removed and/or replaced in the upper West Branch LeClerc Creek watershed. Investigating fish presence surrounding the impacted project area, it was determined that the EBT density had expanded in Saucon Creek which historically was thought to hold a pure, moderately high density WCT population. Saucon Creek is protected from invasion of EBT by a barrier low in the creek near the confluence with West Branch LeClerc Creek. Early efforts to suppress EBT in Saucon Creek occurred from 2003-2005 but ceased due to other project priorities. Provided an unknown EBT distribution, sympatric with what appeared to be an established and moderately high-density population of WCT, a mechanical suppression project using electrofishing techniques was implemented in 2014. The EBT densities were higher than anticipated (in 2014 1,490 EBT removed) and WCT densities were lower than expected (271 captured and returned).

The removal effort was conducted 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 2015, we will conduct one EBT removal treatment consisting of multiple pass depletion techniques (Murphy and Willis 1996, Heimbuch et al. 1997) in continuous 100 m block-netted sections from the barrier at near the confluence with West Branch LeClerc to the extent of observed EBT distribution. Any EBT encountered are removed and WCT are returned no more than 100m from capture location. We will also collect data on population densities of WCT in the allopatric section above the barrier as a reference point once EBT have been completely removed from the project area. In 2016, efforts will continue to suppress EBT in Saucon Creek with a full treatment. We will also collect eDNA samples to determine if EBT are present following the treatment.

MECHANICAL SUPPRESSION ACTIVITIES ADDRESSING LARGE PISCIVOROUS FISH IN MAINSTEM RIVERS OR LAKES

NORTHERN PIKE SUPPRESSION IN BOX CANYON RESERVOIR (PEND OREILLE RIVER, WA): Northern Pike (NP), illegally introduced in the Clark Fork River, Montana have immigrated to the Box Canyon Reservoir (BCR) where they are causing drastic declines in native species and gamefish being managed by the Kalispel Tribe Natural Resources Department (KNRD) , Washington Department of Fish and Wildlife (WDFW) and Idaho Department of Fish and Game (IDFG). The NP population grew exponentially from <400 in 2006 to >5,500 (adults) in 2010 between Newport (Pioneer Park) and Riverbend. Reservoir-wide, the peak population was estimated to be 10,000 individuals in 2011. 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. Efforts to increase the relative abundance of native salmonids in the lower Pend Oreille through mainstem fish passage projects, tributary restoration, and conservation aquaculture may be seriously compromised by unchecked establishment and expansion of NP 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 to emigrate further downstream.  

After engaging the public in 2011 and 2012, KNRD and WDFW developed a 3-pronged approach to suppressing the population to pre-2004 levels: increasing angler harvest through outreach and education, targeted (harvest-oriented) fishing contests (e.g., PikePalooza), and mechanical suppression of the population with gillnets. The objective was to reduce the abundance of NP 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.
Mechanical suppression of NP is an established management tool and efforts have been implemented in the Missouri River drainage, MT, Susitna River drainage, AK, Colorado River drainage, UT, WY, CO, and AZ reservoirs.  Although a variety of methods have been employed for suppression, gillnetting with focused effort on sloughs and backwaters during spring when pike are congregated for spawning has been successfully demonstrated in areas closely mirroring the habitat of Box Canyon Reservoir sloughs. A pilot study in BCR conducted in 2011 confirmed a gillnet removal project was feasible and that intensively netting NP in sloughs and backwaters from ice off through the spring freshet could drastically reduce the abundance of NP in BCR.
KNRD, with support from WDFW has implemented four years of mechanical suppression in BCR (2012-2014) with support provided by BPA, US Bureau of Indian Affairs, WDFW, Kalispel Tribe, and Avista Corporation. Up to 30 gill nets were deployed and retrieved daily from an 18’ (5.5 m) Wooldridge skiff and a 24’ (7.3 m) Almar landing craft work boat outfitted with hydraulic drum roller. Nets used in this project measure 150’ X 6’ (45.7 X 1.8 m) with 5 equal panels of 1”, 1.25”, 1.5”, 1.75” and 2” (2.5, 3.2, 3.8, 4.4, 5.1 cm) meshes, which were developed by KNRD and WDFW in 2010 in consultation with biologists from MN, WI, and Ontario, Canada that have conducted standardized NP surveys for decades. The nets are approximately 45% more efficient at catching NP than WDFW standardized warmwater fish sampling nets and reduce bycatch. Target net saturation generally occurs from ice-off (March) through the spring freshet (June) or ended earlier if target reduction was met (2014) or later phases were unplanned (2015).
From 2012-2015 we removed 16,978 NP in 3,964 overnight gillnet sets in BCR. Based on 2015 Spring SPIN results, the adult population in the core area (southern half of BCR and sloughs) was reduced by nearly 98% from the 2011 baseline of 13.2 NP/net to 0.3 NP/net night. Anglers harvested an additional 334 NP in four PikePalooza fishing derbies (2012-2014) that offered more than $20,000 in cash and prizes. Recreational angler harvest appeared negligible based on observations by field staff 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.

Thus far the project has largely been successful in recruiting and suppressing all available cohorts produced to date. Due to uncertainty about juvenile recruitment and survival under varying water conditions and to also ensure that pre-2004 population abundance is maintained into the future, gillnetting will be necessary at some level.  Based on 2016 Northern Pike suppression and SPIN results, a decision will be made whether to implement suppression in 2017 and to what extent (i.e., duration, total nets, location).  Staff from the Tribe and WDFW will meet in June 2016 and use all available data and information to make the appropriate decision.

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 >26,000 Lake Trout (LKT) removed from 2007-2015. Bull Trout redds are annually monitored in the UPL watershed and have increased from 7 (2007) to 81 (2014), but declined to 54 in 2015.

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 used in UPL are typically 91 m long and range in height from 1.5 to 2.2 m. Individual gill nets were tied together end to end to create a continuous net spanning up to 3,017 m. Gillnets will be fished over a 7 day period in late May/early June 2016. Nets will be set throughout the lake perpendicular to the shore and moved 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 2016 effort will be summarized and compared to previous years’ efforts to monitor the effectiveness and success of the project.

The Tribe’s Non-Native Fish Suppression project (BPA) provides cost-share funding to continue LKT suppression.  The US Fish and Wildlife Service also contributes funding. Continuing to reduce lake trout predation and competition with BT and WCT by removing LKT will assist in Bull Trout recovery and long term persistence of WCT and other native fish populations in the area.

ERADICATION ACTIVITIES ADDRESSING NON-NATIVE EASTERN BROOK TROUT IMPACTS IN TRIBUTARIES

Steady declines in WCT populations located throughout Pend Oreille Basin tributaries have been noted and are in large part due to competition with and predation by non-native salmonids. As such, the KNRD and WDFW are developing 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 unwanted 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 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 trans-located 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 >3,000 WCT in the Cee Cee Ah Creek project area.  We will continue to monitor the population in 2016 by conducting population estimates in each of the 8-1000 m reaches. Multiple pass depletion electrofishing surveys will be conducted in 100 m block-netted sections in each reach. Biological information will be recorded for all WCT captured (i.e., length, weight) and genetic samples will be taken and processed for a future comprehensive analysis of the population. We will also collect several eDNA samples on 2016 to ensure no EBT have been re-introduced to the treatment area.

SMALLE CREEK PISCICIDE TREATMENT EFFECTIVENESS MONITORING (CALISPEL SUBBASIN) : Having established the framework for the program in 2013-2015 (i.e., guiding documents) and funding for the first proposed project on Smalle Creek (Pend Oreille PUD),  KNRD and WDFW, with assistance from Washington State University,  implemented the education and outreach effort necessary to ensure piscicide project success. The upper reaches of Smalle Creek, above a natural barrier, were treated with piscicide in 2015 to remove non-native EBT. This will occur again in 2016 with funding provided by the Pend Oreille PUD. Under the 2016 BPA Non-Native Fish Suppression contract, we will monitor the effectiveness of the 2015-16 treatments by collecting an eDNA sample every 250-300 m of the treatment area. This 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 2017. Once the projects is deemed successful we will restore the WCT population and conduct monitoring protocols (2017-on),

COLLECTING BASELINE INFORMATION ON ALLOPATRIC WESTSLOPE CUTTHROAT TROUT POPULATIONS AS A REINTRODUCTION REFERENCE FOR PISCICIDE PROJECTS: Middle Creek and East Fork Smalle Creek, tributaries to the Box Canyon Reservoir section of the Pend Oreille River, are two of only a few remaining tributaries in Washington's portion Pend Oreille Watershed where allopatric WCT populations exist with sufficient suitable habitat to persist in isolation above a natural fish passage barrier. With nearly 19 km of combined mainstem habitat isolated from invasion by non-native salmonids, East Fork Smalle and Middle Creek WCT provide an opportunity to create reference populations for reintroduction in other areas following piscicide treatments (e.g., Cee Cee Ah Creek and Smalle Creek). They also have potential for use as a source of brood and genetics for reintroduction efforts.  

Under this project, both streams’ WCT populations will be investigated and described from a genetic, biological and demographics standpoint.  Population estimates, physical health of WCT, distribution will be determined in 2016. WCT genetic samples will be collected, in an effort to understand factors such as allelic richness and effective population size, plus the potential suitability of as donor stocks to restore WCT populations elsewhere. To do this a minimum of 50 samples will be taken from each stream, with no more than 10 per 100m, dispersed throughout habitat occupied by WCT.  All samples will be processed by WDFW’s Genetics Lab and a summary will be provided. An overall assessment of the populations will be incorporated into the 2016 Annual Report for this project.