Contract Description:
The Colville Confederated Tribes (CCT) Resident Fish RM&E project is a Columbia River Fish Accord project that began in 2008. The primary goal for the Resident Fish RM&E Project is to conserve, enhance and restore native fish populations in the blocked area above Grand Coulee Dam in Lake Roosevelt and its tributaries, and where appropriate provide opportunities for subsistence harvest by the Colville Tribal members and recreational anglers. The current work of the RM&E project will focus on the protection and conservation of redband trout (Oncorhynchus mykiss gairdnerii) populations on the Colville Confederated Tribes Reservation, with a focus on the Sanpoil River.
Rainbow trout are a focal species in the Sanpoil Subbasin under the Intermountain Province Subbasin Plan (IMP) due to their recreational value as a sport fish and their cultural significance to the CCT (Gillin and Pizzimenti 2004). The Columbia River redband trout are a subspecies of rainbow trout native to the Columbia River drainage east of the Cascade Mountains as far as barrier falls on the Snake, Spokane, Pend Oreille, and Kootenai rivers (Allendorf et al. 1980; Behnke 1992; McLellan and Lee 2010). Effective fisheries management of redband trout requires an understanding of population structure, complex historical management activities, geography, and life history strategies (Small et al. 1998; McCusker et al. 2000; Spidle et al. 2003; Spruell et al. 2003; Small et al. 2007).
Management objectives for the Sanpoil River are to increase adfluvial rainbow trout abundance to support recreational and subsistence harvest (i.e., 1 fish/hr) while maintaining a genetically diverse and natural reproducing population (CCT Fish and Wildlife Management Plan, 2007). However adult spawner abundance objectives have never been determined because limited information exists on each life history type. The Tribe suspects that the bulk of the population is adfluvial with some resident fish. Resident fluvial populations have been found above barriers in many of the tributaries. Because these were not the focus of the habitat improvement project little data has been collected on these populations beyond genetic analysis. Until the Tribe determines what life history forms exist, the extent of their movements and habitats used, what population levels are and how much habitat is available, developing accurate objectives is unattainable.
Two genetically distinct subspecies of rainbow trout have been identified within the Sanpoil Subbasin (Small and Dean 2006, 2007). Redband trout are native to the drainage, while coastal rainbow trout have been introduced to the area (Gillin and Pizzimenti 2004). Native redband may be genetically similar to the native, steelhead populations that were once abundant within the upper Columbia River system (Leary 1997; Gillan and Pizzimenti 2004). Although genetic testing has revealed introgression among subspecies, genetically pure redband trout still exist above barriers (Leary 1997, Small and Dean 2006, 2007). Young et. al. (2007) indicated that greater than 75% of the adfluvial rainbow trout in the Sanpoil system are non-hybridized redband stocks. In order to properly manage the redband population for protection and enhancement of the redband trout populations in the Sanpoil Subbasin, an understanding of population dynamics is necessary along with an understanding of survival in trends during key life-history.
During this contract period the Project will finalize a three study that was implemented in 2010 to determine life history strategies of redband trout and identify key overwintering areas in the Sanpoil River. This work is being conducted by a subcontractor (Pacific Northwest National Laboratories). In addition the Project will begin a redband trout study to monitor trends in abundance of fluvial and adfluvial redband rainbow trout in the Sanpoil River.
DETERMINING LIFE HISTORY STRATEGIES AND OVERWINTER HABITAT USE
The goal of this project is to determine what life histories of rainbow trout exist and how each life history operates within the Sanpoil Subbasin by examining spawning and overwintering movements and habitat use among each life history. Specific project objectives include identification of spatiotemporal patterns in spawning movements and areas used for spawning among life histories within the Sanpoil Subbasin, the identification of overwintering areas of rainbow trout, the investigation of how winter ecology of each present life history is associated with warm groundwater presence, river ice, and other habitat parameters and preliminary investigations of juvenile rainbow trout.
The Colville Tribe has been collecting baseline information on rainbow trout in tributaries to the Sanpoil River since 1990 through the Lake Roosevelt Rainbow Trout Habitat Improvement Project (1990-108-00)(LRHIP). Much of the focus has been towards identifying and improving habitat while minimally assessing the abundance of adult and juvenile migratory (adfluvial) fish in relation to habitat improvements. Some research has been conducted on migratory populations of rainbow trout that use the drainage; however the research efforts do not supply a complete picture because data was usually collected in a haphazard inconsistent manner. In addition, surveys were usually only conducted on tributaries of the Sanpoil, and no surveys have been conducted on the mainstem Sanpoil River.
During the final year of this study, the Project (using the subcontractor) will radio tag 20 additional redband trout to monitor movements and habitat use during the spring and summer periods. An array of 10 receiver stations will be used to monitor movements within the mainstem and timing of tributary entry and exit for each life history stage. Manual tracking will be used in the tributaries to identify spawning locations and habitat use.
By the end of the contract period, a final report will be written that merges all three years of data. Information collected from this study will be used to develop new studies that address potential limiting factors and assist in making future management decisions.
MONITORING TRENDS IN ABUNDANCE REDBAND STUDY
Data currently being gathered on redband adult life histories within the Sanpoil basin have identified three primary life history strategies (fluvial, fluvial-adfluvial and lacustrine-adfluvial) (life histories described by Northcote 1997). Fluvial populations (or resident populations) are documented above barriers and do not migrate extensively within their home range, however a fluvial populations for the mainstem Sanpoil River is still unknown. The fluvial-adfluvial population (migratory cycle between streams or rivers and their tributaries) has been documented within the Sanpoil River drainage; however specific migratory cycles are still not fully understood. The lacustrine-adfluvial population (migrates from Lake Roosevelt into the Sanpoil River) has been found to contain three "components" which include a spring, summer, and fall run. This complex life-history has made this population difficult to understand and study.
Juvenile rainbow trout survival and abundance is also not well understood within the basin. A few surveys have been conducted to monitor juvenile recruitment, in which three distinct age classes have been identified (young of year, one year “parr” and two year “pre-smolt. However, environmental factors and trap efficiency limit an accurate assessment of the numbers of fish in the drainage, when they migrate, or how many migrate when. Juveniles may migrate in late fall or early spring before traps are set. Juveniles have been documented migrating into mid-August (Sears 2000) however recent surveys have been limited to June due to low flows and occasionally extremely high flows.
In 2010 the Colville Tribe began working with regional co-managers to develop a comprehensive plan to monitor the redband trout populations in the blocked area. The Washington Department of Fish and Wildlife (McLellan and Lee 2010) developed a proposal to be used by the co-managers to develop redband stock assessment projects. It was envisioned this document would assist the co-managers with developing similar protocols so that data collected by multiple projects and entities would be compatible and comparable.
This is the outline the CCT has used to develop the Resident Fish RM&E program to conduct stock assessments on redband trout in the Sanpoil River. The project plans to implement four primary tasks which include monitoring abundance, monitoring recruitment, monitoring harvest, and monitoring escapement to assist with management decisions. The development of a multi-year data set will enable managers to monitor trends over time and address potential limiting factors.
Monitoring Abundance will not be part of this contract, but will begin in 2014 and extend through 2017. The CCT’s Lake Roosevelt Habitat Improvement Project (LRHIP) (1990-018-00) will conduct a baseline inventory of redband trout abundance in the Sanpoil River and primary tributaries during the summer of 2013. This inventory will assist the Habitat Project with prioritizing restoration projects, and provide the first data point for the RM&E project to monitor trends over time.
Monitoring Recruitment will begin in 2013 and extend through 2017. The RM&E project will place a series of PIT tag arrays throughout the Sanpoil River basin to estimate recruitment. In 2013, one PIT tag array will be designed and placed at the current weir trap site on the Sanpoil River. Future years will include the addition of 8 other arrays placed at key tributaries to monitor out-migration. The mainstem PIT tag array will be used to document timing of out-migration for both returning adults and out-migrating juveniles (which will be PIT tagged during abundance monitoring in future years). Adfluvial out-migrating juvenile populations will be monitored with a screw trap and the mainstem PIT tag array near mouth of Sanpoil River.
Monitoring Harvest of redband trout will begin in 2013 and extend through 2017. The RM&E project will use two creel surveys to monitor harvest of redband trout. For fluvial populations found in the mainstem Sanpoil River, the project will conduct a 7 month creel survey (May – Nov) to estimate harvest within the river. The project will conduct this survey for three years in order to gain accurate estimates on harvest. After this point, the project will determine if the River surveys should be continued. The project will coordinate with the Lake Roosevelt Fisheries Evaluation Project (1994-043-00) to obtain creel information on wild rainbow trout. Creel clerks scan all wild rainbow trout for PIT tags. The project will estimate harvest impacts from these data.
Monitoring Escapement of adult rainbow trout will continue into 2013 and extend through 2017. The RM&E project will monitor lacustrine adfluvial escapement into the Sanpoil River from a weir trap installed near the mouth of the river. The project will operate the weir for two full years beginning in 2012 to identify escapement times (spring, summer and fall). After that (2014), the project will operate the weir only at the critical times. The mainstem PIT tag arrays will also be used to track movements of spawning fish within the system. The fluvial populations will be monitored using the 8 arrays set in the primary tributary mouths.
The development of a standardized stock assessment project will enable biologists to estimate the current status of the redband stock relative to management targets. These estimates will then be used to suggest management activities to improve abundance of redband trout.