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Northern Pike Esox lucius are a highly invasive fish species that can significantly reduce fish densities and cause large-scale changes in fish communities. Northern Pike pose significant threats to the Columbia River ecosystem as a result of predation and competition for food resources. In addition, they may pose an extinction risk for sensitive species. The increasing observations of Northern Pike in Lake Roosevelt prompted the Lake Roosevelt co-managers (Colville Confederated Tribes, Spokane Tribe of Indians, and Washington Department of Fish and Wildlife) to implement surveys to investigate abundance, diet, growth, origin, spawning locations, and movement patterns. Aggressive removal plans have been designed and are being implemented in the upper reaches of Lake Roosevelt and Kettle River. The goal of the project is to suppress Northern Pike in Lake Roosevelt watershed and to prevent them from spreading further downstream in the Columbia River system. The co-managers will use a multi-teared approach that includes mechanical removal techniques, angler incentives, and limited monitoring and research. |
Lake Roosevelt Northern Pike Suppression and Monitoring Project (Proposed)
The goal of the Northern Pike Suppression and Monitoring Project is to suppress or eradicate Northern Pike in the Lake Roosevelt watershed.
Northern Pike Esox luscious are native to the mid-western United States, parts of Alaska, and the Saskatchewan River drainage in Montana (Wydoski and Whitney 2003). The legal and illegal stocking of Northern Pike in the 1950’s contributed to their establishment in the Blackfoot, Bitterroot, and Clark Fork systems in western Montana. By the 1970’s they had expanded their range into the Flathead system (Bernall and Moran 2005). An illegal stocking event also led to their expansion in the Coeur d’Alene River system in the mid 1970’s, and eventually throughout much of the Spokane River (Bennett and Rich 1990).
By 2004, Northern Pike had expanded into the Pend Oreille River system in Idaho (Connor and Black 2010). Five years later, Northern Pike were observed in the Canadian section of the Columbia River, below Keenleyside Dam in British Columbia (Baxter and Neufeld 2015).
The first Northern Pike was documented in Lake Roosevelt in 2007 (Lee et al. 2010) and first observed in the recreational fishery in 2011 (Blake et al. 2017). They are now routinely captured by anglers and have been increasing in the abundance during standard reservoir surveys (Seibert et al. 2015; King and Lee 2016; Blake et al. 2017; Howell and McLellan 2017).
Northern Pike are highly invasive and have been shown to significantly reduce prey fish densities when introduced to new waters. When introduced, they have the potential to cause large-scale changes in fish communities, even species elimination (He and Kitchell 1990; McMahon and Bennett 1996; Baxter and Neufeld 2015).
The introduction and expansion of Northern Pike into non-native waters has been a concern of many State and Provincial Fish Management agencies. To address the ecological threat Northern Pike pose in new systems, many states have developed suppression or management plans including Alaska (South Central Alaska Northern Pike Control Committee; Smukall 2015), Colorado (2015 Colorado Parks and Wildlife), Utah (2017 Utah Division of Fish and Wildlife), and Maine (Lucas and Brautigam. 2008) as well as Canadian Provinces (Baxter and Neufeld 2015; Baxter 2016; Baxter and Doutaz 2017) that support liberal harvest limits or require Northern Pike be killed if captured. Angler reward programs have also been instituted in some states. Colorado is offering a $20 reward for each Northern Piker killed in Green Mountain Reservoir in Colorado (http://cpw.state.co.us/aboutus/Pages/News-Release-Details.aspx?NewsID=6142).
Idaho and Montana have managed for Northern Pike over the past 50 years and have recently liberalized harvest regulations and implemented studies to monitor Northern Pike impacts on native salmonids such as Bull Trout Salvelinus confluentus and Westslope Cutthroat Trout Onchorhynchus lewisi clarkii (Bernall and Moran 2005; Walrath, J.D. 2013).
The State of Alaska has implemented a variety of Northern Pike control measures for both lentic and lotic habitat types. Depending on the habitat type, actions such as barriers, habitat manipulation (dewatering/vegetation removal), mechanical removal (electrofishing, gill netting), bounty programs, and chemical treatments have been implemented with varying levels of success (South Central Alaska Northern Pike Committee). In their review, dewatering habitat and chemical treatments (rotenone) were effective techniques for eliminating Northern Pike, with other techniques having varying success depending on the habitat type.
Northern Pike abundance began to noticeably increase in Box Canyon Reservoir of the Pend Oreille River, Washington, in 2006 (Connor and Black 2010). The population grew exponentially from less than 400 individuals to more than 5,500 by 2010 (Anderson and Bean 2013; Bean 2014). The population doubled the following year to over 10,000 in 2011 (Anderson and Bean 2013). The increase in abundance caused noticeable changes to the fish community, with significant declines in native and managed game fishes (Bean et al. 2011). Northern Pike were threatening to undermine the recovery efforts for Bull Trout and Westslope Cutthroat Trout in the system.
The Kalispel Tribe, in partnership with the Washington Department of Fish and Wildlife (WDFW), implemented an aggressive mechanical removal program that targeted spawning locations between March and April 2012-2015 (Bean 2014; Bean et al. 2014; Bean and Harvey 2015; Harvey and Bean 2016). The program set approximately 1,000 gill nets overnight each spring and were able reduce the catch-per unit-of-effort (CPUE) from 12.2 Pike/net to less than 0.18 Pike/net during annual Spring Pike Index Netting (SPIN) surveys (Harvey and Bean 2016).
The Box Canyon Reservoir Northern Pike suppression effort has largely been successful (Bean 2014; Bean 2015; Harvey and Bean 2016). The Kalispel Tribe, in coordination with Seattle City Light and WDFW, have expanded their mechanical removal efforts downstream to Boundary Reservoir on the Pend Oreille River in order to reduce the spread of Northern Pike into downstream waters, including Lake Roosevelt.
The co-managers of Lake Roosevelt, the reservoir upstream of Grand Coulee Dam, (Colville Confederated Tribes, Spokane Tribe of Indians, and the WDFW), mutually agree that an aggressive removal program, similar to the Kalispel Tribe’s Program, is necessary to curb the expansion of the Northern Pike population in Lake Roosevelt and prevent expansion into downstream areas of the Columbia River with anadromous and other sensitive fish populations.
In 2014, the Spokane Tribe of Indians (STOI), in collaboration with WDFW and the Colville Confederated Tribes (CCT), submitted a request for funding to the Northwest Power and Conservation Council, through the BOG process, to support Northern Pike monitoring and suppression in Lake Roosevelt. In 2015, the Council provided limited funding to monitor and suppress Northern Pike.
In 2017, CCT collaborated with BPA to create a new CCT Pike Removal Project under the umbrella of the STOI LRFEP Project that was already ISRP reviewed. In 2017, the Spokane Tribe requested additional funding through the Budget Oversight Group (BOG) process to support Northern Pike removal efforts. The STOI request was approved in August of 2017.
In 2017, the Lake Roosevelt Northern Pike Technical Team finalized a Lake Roosevelt Northern Pike Suppression and Monitoring Strategy that uses key principles outlined in the Northwest Power and Conservation Council’s (NWPCC) 2014 report for managing non-native and invasive species (NWPCC 2014) and meets the goals set forth in the Lake Roosevelt Guiding Document (2008).The Suppression Strategy uses a multi-teared approach that includes three key elements; 1) a suppression strategy to control or eliminate Northern Pike, (2) a research strategy to fill data gaps, and (3) an education and public outreach strategy that will inform the public on the adverse effects of Northern Pike introductions.
The Northern Pike Suppression and Monitoring Strategy utilizes multiple mechanical removal techniques (gill netting, fyke netting, seining), angler incentives ($10/head Reward Program), monitoring (microchemistry, eDNA, reservoir operations modeling) to achieve the stated goals.
The Lake Roosevelt Northern Pike Suppression and Monitoring Strategy is partially funded by Bonneville Power Administration (BPA). Other organizations that have contributed funds including Grant County Public Utility District (PUD), Chelan County PUD, CCT, Avista Utilities, STOI, and WDFW.