Rufus Woods Lake’s rise as a popular regional area for catching large (total length [TL] =500 mm) Rainbow Trout Oncorhynchus mykiss coincided closely with the establishment of net pen aquaculture in its waters, which first appeared in 1989 (Shallenberger 2010).  Throughout their history on Rufus Woods Lake, various iterations of net pen aquaculture sites and ownership led to a range in Rainbow Trout escapement.  Escapements of large Rainbow Trout from net pen facilities resulted in increased fishing opportunities (Shallenberger 2010).  The Colville Confederated Tribes (CCT) further recognized the potential use of net pen facilities to increase Rainbow Trout numbers in Rufus Woods Lake.  In coordination with Columbia River Fish Farms, CCT funded Rainbow Trout supplementation from 1997 to 2005 and released more than 200,000 fish.  Additionally, during 1996–1999, a study documented thousands of fish entering Rufus Woods Lake from Lake Roosevelt (upstream reservoir on the Columbia River) by entraining past Grand Coulee Dam (LeCaire 1999).  Word spread about the opportunities for large Rainbow Trout throughout this period, and Rufus Woods Lake became a popular fishing destination for anglers (Shallenberger 2010).  In 2002, the Washington State record Rainbow Trout was caught in Rufus Woods Lake (13.4 kg).

Previous years' creel data suggested catch and catch rates of large Rainbow Trout were maintained at high levels due to fish escapement from aquaculture net pens located within Rufus Woods Lake, not from CCT fish purchases and stocking efforts (Shallenberger 2010; Keleher and Cross 2015a).  Specifically, from 2006 to 2008, total fish escapement estimates ranged between 300,000–400,000 fish (Shallenberger 2010).  The result was more than 40,000 angler days spent on Rufus Woods annually, which made Rufus Woods the most popular fishing destination on the CCT Reservation (Shallenberger 2009).  Stocking by CCT accounted for a large portion of harvested Rainbow Trout from 2007–2010 during periods when escapement was low, but most stocked catchable size Rainbow Trout only contributed to the fishery within the first month of their release (Shallenberger 2009 and 2010; Keleher and Cross 2015a).  In 2011 throughout the reservoir, angler effort reached 55,009 hours in June and 90,223 hours in July with Rainbow Trout catches of 32,356 and 39,384 in June and July, respectively (Keleher and Cross 2015a).  Abnormally high flow conditions during spring runoff in 2011 lead to prolonged exposure to elevated total dissolved gas (TDG) levels (>120% for 40 consecutive days).  The high TDG caused fish mortalities in the net pens, which led to the nets being weighed down and caused a mass escapement of Rainbow Trout.  The accidental escapement led to the large increase in angling effort and catch observed in Rufus Woods Lake in June and July of 2011 and carried over into 2012 (Keleher and Cross 2015a).  Annually maintaining a Rufus Woods Lake Rainbow Trout fishery that produces the high angling effort, catch rate, harvest, and average fish size seen in years with large net pen escapements has proven challenging for fisheries managers.

Maintaining a Rainbow Trout fishery in Rufus Woods Lake similar to that experienced during periods with high net pen escapement would require resources beyond those available to CCT Fish and Wildlife Department.  Rearing or purchasing large Rainbow Trout for release into the reservoir in numbers similar to those that previously escaped was cost prohibitive.  To achieve a fishery similar to one maintained by high net pen escapement, tens-of-thousands of Rainbow Trout greater than 500 mm TL would need to be stocked, or smaller stocked Rainbow Trout (~250 mm TL) would need to grow beyond 500 mm.  During 2009–2014, several thousand Rainbow Trout that averaged 1,660 g (3.69 lb) each were purchased directly from local aquaculture facilities and stocked into Rufus Woods, but this stocking did not mimic numbers seen during previous escapements.  Additionally, previous studies have shown little potential for the success of a put-grow-and-take fishery in Rufus Woods due to underutilization of the prey-base by released fish (Richards et al. 2011, Rensel et al. 2013).  Thus, realistic and achievable management objectives and actions that account for a balance between the numbers and size of fish released needed to be determined.

The goal of this project is to provide fisheries managers with information (status and trend monitoring) that assists with the development and maintenance of a subsistence fishery for CCT Tribal members and a quality sport fishery for members and non-members while conserving native species.  Management objectives were established in 2015 for CCT stocked waterbodies (CCTFW 2015).  The specific objectives for Rufus Woods Lake are to provide a fishery that consists of a total annual angler harvest of 40,000 Rainbow Trout, with more than 49% of these fish measuring over 400 mm and 5% measuring over 500 mm.  The targeted management actions established to reach this goal included annually stocking 50,000–75,000 Rainbow Trout =400 g/fish (CCTFW 2015).  The creel survey was used to guide fish stocking efforts and determine if management objectives were being met by management actions.  Specifically, the creel survey estimated:

1.    Shore, boat, and total angler effort (angler-hours).
2.    Average catch and harvest rate (number of fish per angler-hour) for all Rainbow Trout and individual sources of Rainbow Trout (when possible).
3.    Total catch and harvest for all Rainbow Trout and individual sources of Rainbow Trout (when possible).
4.    Harvested fish size statistics (length) for all Rainbow Trout and individual sources of Rainbow Trout (when possible).

Finally, native Redband Trout are a conservation priority for the Colville Confederated Tribes, and the level of entrainment into Rufus Woods Lake and utilization of Nespelem River habitat will be documented to inform conservation efforts.  As such, a PIT antenna arrays was installed in the summer of 2018 and will be used to quantify the number of native Redband Trout entraining into Rufus Woods Lake from Lake Roosevelt (i.e., Sanpoil River origin) and utilizing habitat available in the Nespelem River.  This information will be used to assess relative changes in native Redband Trout abundance as a result of possible future management actions, including interactions with released triploid Rainbow Trout.