Kokanee

 

A total of 5 million kokanee eggs are needed to meet annual release goals of 3.7 million kokanee fry and 250,000 kokanee yearlings.  Egg availability is dependent on annual adult return run size and is an ongoing limiting factor.  Currently, three stocks of kokanee are used to meet annual release goals.  In order of preference, they are the Lake Roosevelt mixed stock, Meadow Creek stock, and Lake Whatcom stock. 

 

A limited number of eggs are collected from mature kokanee returning to tributaries in the fall. This stock, Lake Roosevelt Mixed stock, is comprised of spawning returning Meadow Creek stock fish.  Past attempts at collecting eggs from other collection sites have been unfeasible, but adult returns to Hawk Creek have shown the potential for a locally adapted stock of kokanee.  Up to 3.2 million kokanee eggs are potentially available from the British Columbia Freshwater Fisheries Society Meadow Creek Kokanee Program.  This stock is preferred over the Lake Whatcom stock because it is an upper Columbia River origin stock and has been proven to have higher survival rates in the reservoir when compared to the Lake Whatcom stock (McLellan et al. 2002, 2003).  Up to 1.8 million kokanee eggs are provided by the Washington Department of Fish and Wildlife’s Lake Whatcom Hatchery Program. .  Egg availability from all three sources is dependent on annual adult returns.

 

All kokanee eggs are thermally marked at Washington Department of Fish and Wildlife’s Spokane Hatchery.  Once marked, eggs are transferred to the Spokane Tribal Hatchery for subsequent rearing.  Kokanee fry are released (350/lb.) in June at the deep-water release site (Seven Bays).  Approximately 300,000 fry are carried over to meet annual yearling kokanee release goals.  To alleviate space constraints at the Spokane Tribal Hatchery yearling kokanee (currently approximately 100,000) to be released in June are transferred to the Sherman Creek Hatchery and released in June.  The release goals for the kokanee program are 250,000 yearlings to be released at the Fort Spokane boat launch and the remaining 2-4.5 million Whatcom/Meadow Creek fry to be released in the open water at Seven Bays.  In years when Meadow Creek eggs are unavailable Lake Whatcom eggs are used to meet annual yearling release goals.  A flow chart has been provided that displays the transfer of kokanee between the two hatcheries (Figure 2).

 

The total number and stock of kokanee eggs received from 2007-2011 are presented in Table 6.  The percent survival to feeding fry, number of fry reared to distribution, percent survival to distribution, number of fry released, size (fish/lb.) of fry at release, release site, and number of fry carried over to meet annual yearling production goals are also displayed in Table 6. 

 

Release year, stock, broodyear, and number of kokanee reared to distribution from 2007 through 2011 are displayed in Table 7.  Percent survival to distribution, number of yearling kokanee transferred to Sherman Creek Hatchery, number of kokanee yearlings released from the Spokane Tribal hatchery, size (fish/lb.) at release, and release location are presented in Table 7.

 

Yearling kokanee production from 2007 through 2011 at Sherman Creek Hatchery is outlined in Table 8.  The date the yearlings were received at Sherman Creek Hatchery, the number transferred, size (fish/lb.) at transfer, date of release, number of yearling kokanee released, size (fish/lb.) at release, release location, percent mortality, unknown loss, percent fin clipped, and type of fin clip are presented in Table 8.

 

Release year, total number of adipose fin clipped yearling kokanee released, harvest of adipose fin clipped kokanee, condition factor of adipose fin clipped kokanee, and mean growth (total growth for four months)for adipose fin clipped kokanee from time of release till time of capture  is presented in Table 9.

 

 

 

 

 

 

 

Figure 2.     A flow chart of kokanee salmon transfers between the Spokane Tribal hatchery and Sherman Creek hatchery.

 

 

Table 6.      Kokanee salmon: Year, stock (WHAL = Lake Whatcom stock, MEAD = Meadow Creek stock), broodyear, number of eggs received at the Spokane Tribal Hatchery, number of kokanee eggs hatched, percent survival to feeding fry, number of fry reared to distribution, percent survival to distribution, number of fry released, release site, and number of kokanee fry held over for yearling releases into Lake Roosevelt, WA from 2007-2011.

Release Year	Stock:BY	Eggs Received	Number Hatched	% Survival to Feeding Fry	Number of Fry Reared to Distribution	% Survival to Distribution	Number of Fry Released	Release Site	Fry Carried Over at STH
2008	WHAL:07	1,801,470	1,743,395	97%	1,291,614	74%	483,300	Hawk Creek	438,114
							115,200	Hawk Creek	-
2009	MEAD:08	3,100,000	2,911,912	94%	2,505,514	86%	1,236,620	Seven Bays	251,874
							582,140	San Poil River	-
							434,880	Fort Spokane	-
2009	WHAL:08	1,801,152	1,726,580	96%	1,646,016	95%	1,263,744	Seven Bays	-
2010	WHAL:09	1,102,200	1,072,082	97%	589,580	79%	589,580	San Poil River	260,641
2011	WHAL:10	2,464,017	2,320,474	94%	1,695,526	84%	1,695,526	Seven Bays	259,756
							35,120	Fort Spokane	-

 

 

Table 7.      Kokanee salmon: Year, stock (WHAL = Lake Whatcom stock, MEAD = Meadow Creek stock, ROOS = Lake Roosevelt mixed stock), number reared to distribution, percent survival to distribution, number transferred to SCH (Sherman Creek Hatchery), number released, size (fish/lb.) at release, and release site for kokanee yearlings released into Lake Roosevelt, WA from 2007-2011.

Release Year	Stock:BY	Number of Yearling Kokanee Reared to Distribution	% Survival to Distribution	Fish Transferred to SCH	Number of Yearlings Released	Size (fish/lb.)	Release Site
2007	MEAD:05	330,180	96%	84,480	19,500	10.0	Little Falls Dam
					213,600	9.5	Fort Spokane
					13,200	8.0	Onion Creek
2007	WHAL:05	91,320	91%	75,320	16,000	8.0	Fort Spokane
2008	WHAL:06	530,820	77%	204,586	302,330	13.3	Fort Spokane
					23,904	9.0	Little Falls Dam
2009	ROOS:07	2,790	12%	-	2,790	1.5	Fort Spokane
2009	WHAL:07	469,748	93%	213,200	242,196	15.6	Fort Spokane
					14,352	13.0	Little Falls Dam
2010	ROOS:08	12,420	77%	-	12,420	3.0	Fort Spokane
2010	MEAD:08	218,285	87%	99,480	10,080	9.0	Sanpoil River
					97,365	6.9	Fort Spokane
					11,360	8.0	Little Falls Dam
2011	LR:09	11,102	96%	-	11,102	2.0	Fort Spokane
2011	WHAL:09	223,652	86%	134,062	20,360	10.5	Sanpoil River
					69,320	8	Fort Spokane

 

 

 

 

Table 8.      Kokanee salmon: Release year, stock, broodyear, date transferred to Sherman Creek Hatchery, size (fish/lb.) at transfer, date released, size (fish/lb.) at release, percent mortality, unknown loss/overrun, release site, percent marked, and markt ype (AD = adipose fin clip, LV = left ventral fin clip, RV = right ventral fin clip) for kokanee salmon released into Lake Roosevelt, WA from 2007-2011.

Release  Year	Stock:BY	Date	Number  Transferred	Size  (fish/lb.)	Date	Number  Released	Size  (fish/lb.)	% Mortality	Unknown Loss /Overrun	Release Site	%  Marked	Mark
2007	MEAD:05	4/17/2007	84,480	12	5/21/2007	71,772	9.5	0.60%	-12,151	Onion Creek	100%	AD, RV
2007	WHAL:05	4/18/2007	75,320	14	6/4/2007	81,235	13.3	1.50%	+7,001	Fort Spokane	100%	AD, LV
2008	WHAL:06	4/21/2008	204,586	16.2	5/30/2008	159,564	13.2	2.30%	-45,022	Fort Spokane	100%	AD
2009	WHAL:07	4/9/2009	213,200	15.89	6/10/2009	241,870	16.58	0.03%	+29,351	Fort Spokane	100%	AD
2010	MEAD:08	4/21/2010	99,480	10.4	6/2/2010	80,784	7.78	0.50%	-18,331	Fort Spokane	100%	AD
2011	WHAL:09	4/11/2011	134,062	14.2	5/31/2011	130,631	12	0.70%	-2,395	Fort Spokane	100%	AD

 

 

 

 

Table 9.      Kokanee salmon: Release year, number of yearling kokanee released, annual hatchery kokanee harvest, condition factor (SD), and mean growth (calculated for a four month time span from when fish are released to recaptured) for yearling kokanee released in Lake Roosevelt, WA from 2007-2011.  Harvest and condition factor data for 2010 are preliminary.

Release Year	Number of Yearlings Released	Harvest	KTL	Mean Growth (mm)
2007	415,307	122	1.23 (0.15)	1541
2008	530,820	368	1.16 (0.14)	1712
2009	501,208	1,086	1.36 (0.29)	1713
2010	212,009	1,842	1.10 (0.16)	N/A
2011	211,053	N/A	N/A	N/A
1McLellan et al. 2007
2McLellan et al. 2008
3McLellan et al. 2009

 

 

 

 

2. “In the latest annual report, the sponsors note that due to high snowpack and resulting short water retention time in Lake Roosevelt many fish were entrained through Grand Coulee dam last year. This comment should be expanded upon and any estimates of entrainment provided in the response.”

 

High snowpack and short water retention times are commonly associated with loss of fishing opportunities in a reservoir system such as Lake Roosevelt, however numerical estimates of entrainment for 2011 are not available.  It should be noted, however, that when a volunteer net pen program recognized as providing a successful put and take fishery year after year is faced with an eighty foot, flood control drawdown, one might tend to draw conclusions. I think this comment was reflective of the frustration the volunteers feel when dealing with spring drawdown similar to those observed in 2011 for Lake Roosevelt.

 

 

 

3. “The kokanee portion of the project is showing some improvement. The goal of 5% kokanee harvest following release should be compared with other systems to justify this small level of survival and harvest after only a few months in the reservoir. The goal for the rainbow trout program of 50,000 to 150,000 fish harvested or 20% of release also needs to be considered in comparison to other large reservoir systems for the ISRP, Council, BPA, and stakeholders. This comparison will help place this program in context with other similar put-grow-and-take efforts, for example Lahontan cutthroat trout in Pyramid Lake, Nevada and rainbow trout in Flaming Gorge in Wyoming/Utah.”

 

Lake Roosevelt has hydrological, morphological, and ecological characteristics unlike many other reservoirs and lakes that makes it difficult to compare to other regional systems.  Lake Roosevelt is impounded by Grand Coulee Dam, which is one of the largest concrete structures in the world.  Lake Roosevelt consists of different temporal and spatial characteristics.  Lake Roosevelt at a full pool elevation of 393 m (1,290 ft) inundates 33,490 hectares (82,691 acres) with a storage capacity of 1.16 × 10¹⁰ m³ (9.41 × 10¹⁰ acre-ft) and a maximum depth of 122 meters (400 ft; Nigro et al. 1981).  At 243 km long, Lake Roosevelt is the largest reservoir in Washington, the sixth largest reservoir in the U.S., and one of the largest artificial lakes in the world (Johnson et al. 1991).  Lake Roosevelt is regulated by extensive hydro-operations at Grand Coulee Dam resulting in deep drawdowns in excess of 20 meters and a mean water retention time (WRT) of only 45 days.  Lake Roosevelt is a highly dynamic, oligotrophic system that is pelagically driven as a result of deep spring drawdowns that have essentially eliminated the development of a littoral zone and associated macroinvertebrate communities.  Incomplete thermal stratification occurs in portions of the reservoir due to hydro-operations.  Lake Roosevelt is more comparable to a large river than to a lake or reservoir (Black et al 2003).

 

Harvest goals for rainbow trout in Lake Roosevelt range between 50,000 to 150,000 fish and are based on a logistic regression model that estimates harvest percents based on the hydro-operations of a given year.  Hydro-operation variables including water retention time and reservoir elevation pre-and post-release are incorporated into the model.  Hydro-operations associated with Grand Coulee Dam negatively affect the rainbow trout fishery in Lake Roosevelt either through increased levels of entrainment or mortality due to unstable reservoir conditions (McLellan et al 2008). 

 

Flaming Gorge Reservoir is an impoundment of the Green River and extends through Wyoming and Utah.  At an elevation of 1,841 meters above mean sea level, Flaming Gorge Reservoir occupies over 42,000 surface acres, impounds 17,000 ha of water, is 145 km long, and has a mean depth of 34 m (Haddix and Budy 2005; USBR 2012).  The reservoir is characterized by three distinct areas, differing in morphological characteristics and productivity.  Thermal and chemical stratification occur in the reservoir and water retention time in Flaming Gorge is 2.3 years. 

 

Flaming Gorge Reservoir is managed as “basic yield” fishery.  Between the years of 1998 and 2003, 0.6 to 1.3 million fingerling rainbow trout were reported to have been stocked into Flaming Gorge Reservoir (Mosely et al 2003).  Total harvest derived from creel data for rainbow trout and kokanee in 2003 was reported to be 42,566 and 24,827 respectively.  Stocking records obtained from the Utah Division of Wildlife Resources indicate that between 2002 and 2003 less than 20,000 kokanee were stocked, indicating that a large portion of the 2003 harvest may have been from carryover fish.

 

In contrast, Pyramid Lake is a large natural desert lake in northern Nevada that lies within the boundaries of the Pyramid Lake Paiute Tribe Reservation.  The lake occupies approximately 112,000 surface acres with 125 miles of shoreline and is not regulated by any hydro-operations.  Pyramid Lake is fed by the Truckee River and has no outlets.  The geology surrounding Pyramid Lake is characterized by large calcium carbonate tufa mounds and is very different from that of Lake Roosevelt.

 

Pyramid Lake fish managers work to enhance native Cui-ui and Lahontan cutthroat trout populations, and maintain a trophy fishery for Lahontan cutthroat trout (LCT).  More than 830,000 LCT were released into Pyramid Lake between 2000 and 2005, and from 2006 through 2010, more than 334,000 LCT were released into Pyramid Lake and the Lower Truckee River.  Total harvest reported from 2008-2009 creel data was 5,548 fish (http://plpt.nsn.us/).  Quantifiable harvest goals for Lahontan cutthroat trout in Pyramid Lake are unknown.

 

Ecological conditions in Lake Roosevelt are strongly affected by hydro-operations and differ greatly from Flaming Gorge Reservoir and Pyramid Lake.  Characteristics that differ between systems include but are not limited to: elevation, lake/reservoir size, thermal and chemical stratification, productivity, trophic status, hydrology, geomorphology, fish species, and management objectives.  Without knowing specific management goals for stocking rates and harvest in Flaming Gorge Reservoir and Pyramid Lake, and in consideration of vastly different physical and biological characteristics, it is difficult to make a fair comparison of these three systems.

 

 

 

4. “Additional consideration is needed with Washington trout stocking programs, and whether this project is consistent/compliant with the State of Washington policies on hatchery operations, fish release, harvest yields, and native species interactions.”

 

• The Lake Roosevelt Artificial Production Programs are consistent with co-managers goals and policies for Lake Roosevelt and are coordinated through the Lake Roosevelt Fisheries Guiding Document. This coordination is consistent with the state policies on fish health, invasive species prevention, fish hatchery operations, hatchery stocking plans including the WDFW Future Brood Document, and with native species interactions and concerns.  All fish culturing methods used by the Lake Roosevelt Artificial Production Programs follow the standardized Washington Department of Fish and Wildlife’s Fish Health Manual (uploaded in Pisces under Sherman Creek Hatchery (BPA Project 1991-047-00)).

 

 

5.”The questions are: Can the project obtain the rainbow trout and kokanee eggs it needs? What are the broodstock or egg collection goals? What are the facility monitoring for water quality and discharge?”

 

Rainbow Trout and Kokanee Egg Sources

 

 

 

Rainbow Trout Eggs

 

 

 

Beginning in 2007, production of triploid Spokane stock rainbow trout increased to 750,000. The Spokane Tribal Hatchery obtains 1.1 million triploid Spokane stock eggs annually from the WDFW Spokane Trout Hatchery in the winter (Dec-Jan) for culturing and fry to juvenile production (Jan-Oct).  Approximately 300,000 juveniles are transferred to the WDFW Sherman Creek Hatchery in July to alleviate rearing capacity issues at the Spokane Tribal Hatchery.   Assuming survival rates of 80% egg to fry, and 90% fry to juvenile, approximately 750,000 triploid Spokane stock rainbow trout are collectively produced for transfer to Lake Roosevelt net pen rearing operations in the fall (Oct-Nov).  All fish are marked with adipose fin clips prior to transfer to the net pens.  The Lake Roosevelt Rainbow Trout Net Pen Project coordinates volunteers to feed the trout, maintain the net pens and release the fish after refill begins following reservoir drawdown for spring flood control, and when zooplankton biomass is adequate for forage (May-June).

 

 

 

Kokanee Salmon Eggs

 

 

 

The Spokane Tribal Hatchery and Sherman Creek Hatchery work collectively to produce 2.7 million kokanee fry and 250,000 kokanee yearlings annually for release into Lake Roosevelt.  A total of 5 million kokanee eggs are required to meet the release goals.  Egg availability is an ongoing limiting factor dependent on annual adult return run size.  Available eggs (in order of co-manager preference) are obtained from the following sources:

 

1. Lake Roosevelt Mixed Stock:  Currently a limited number of eggs are collected from mature kokanee captured during surveys of adult returns to tributaries (i.e. Hawk Creek) in the fall.
2. Meadow Creek Stock:  Up to 5 million kokanee eggs are potentially available for allotment to the Lake Roosevelt Artificial Production Program from the British Columbia Fisheries Meadow Creek Kokanee Program.  Meadow Creek, B.C. stock is a preferred stock for supplementation into Lake Roosevelt because it is an in-basin origin stock, and has been proven to have higher survival rate in the reservoir than the Lake Whatcom Stock (McLellan and Scholz, 2002, 2003).
3. Lake Whatcom Stock:  Up to 1.8 million eggs are potentially available for allotment to the Lake Roosevelt Artificial Production Program from the WFW Lake Whatcom Hatchery Program.

 

 

Kokanee fry production begins with egg culturing of up to 5 million eggs at the Spokane Tribal Hatchery.  Assuming survival rates of 80% egg to fry and 90% fry to juvenile, approximately 3.5 million fry are produced to target the release goals.

 

 

 

Kokanee yearlings are produced from fry carried over at the Spokane Tribal Hatchery.  Approximately 100,000 kokanee of 250,000 carried over are transferred to the Sherman Creek Hatchery in early spring to alleviate rearing capacity issues at the Spokane Tribal Hatchery.  Collective releases of up to 250,000 yearlings occur during or after reservoir refill in conjunction with zooplankton biomass sufficient for forage (mid-may to June).  Release location and numbers include up to 25,000 at Little Falls Dam to support a tribal fall subsistence fishery and up to 250,000 at Ft. Spokane to support reservoir-wide recreational and tribal fisheries.

 

 

 

Broodstock/Egg Collection Goals

 

 

 

The production goal for rainbow trout is to produce 750,000 Spokane stock trout, 98% or greater adipose clipped, and 98% or greater triploided, from the Spokane Tribal and Sherman Creek hatcheries for release into Lake Roosevelt.

 

 

 

Productions goals for kokanee in Lake Roosevelt are as follows:

 

 

 

1. Produce from Spokane Tribal Hatchery and Sherman Creek Hatchery 250,000 yearling Meadow Creek kokanee.  If Meadow Creek eggs are not available, the Lake Roosevelt stock or Whatcom stock will be used as a substitute, in that order preferentially.

 

 

1. Produce from Spokane Tribal Hatchery 2 million Whatcom/Meadow Creek fry for open water release into the lentic portion of Lake Roosevelt.

 

 

1. Production of Meadow Creek and Localized stock from Hawk Creek Egg collection facility.  If production goals are not met by 2020 the program should be suspended.
   1. Produce 50,000 Meadow Creek and Lake Roosevelt localized stock fry by 2011.
   2. Produce 150,000 Meadow Creek and Lake Roosevelt localized stock fry by 2015.
   3. Produce 500,000 Meadow Creek and Lake Roosevelt localized stock fry by 2020.

 

 

1. Seed 1 million Meadow Creek eyed eggs into Sanpoil River basin and Barnaby Creek. If Meadow Creek eggs are not available Whatcom stock will be used as substitute.

Water Quality Monitoring

 

Water Quality is monitored on all three projects for fish health concerns including total dissolved gasses, dissolved oxygen, temperature, etc.

 

Water discharge monitoring is not routinely conducted at Sherman Creek or at the net pen sites since this is not required under the State of Washington nor the NPDES requirements / permits.  The net pens are further included in the Categorical Exclusion provided by BPA Environmental Compliance, (see attached).  We do however, monitor water conditions if concerns arise.  Additionally, the Colville Confederated Tribes had a study done in 1998 to examine net pen effects on Lake Roosevelt and possible effects on aquatic productivity, (Rensel, 1999).

 

 

 

6.“The ISRP looks for clear metrics for performance in the hatchery including broodstock or egg collection goals, egg to fry survival, fry to sub-catchable or catchable survival, disease or other health inspections, and food conversion as well as post-release performance including survival for stated intervals, harvest, and fish condition. There may also be facility related metrics for discharge water quality.  The metrics for fish production including life-stage survival, condition factor, and fish health as well as facility operations including water discharge and invasive species inspections are not presented and need to be included.”

 

Project sponsors recognize the need for clear performance metrics.  Lake Roosevelt artificial production projects implemented resident fish versions of Hatchery Genetic and Management Plans as a result of the NWPCC Artificial Production Review process.  The projects utilize standardized protocols for prudent fish culturing practices as listed in their respective annual operating plans.  Categorical metrics and methods summarized from respective annual operating plans are listed below.

 

 

 

Life Stage Survival Rates

 

The general assumptions for survival include 80% from initial incubation to feeding fry, 90% from fry to juvenile and 90% from distribution to release.  Projections at each life stage for rainbow trout and kokanee salmon are listed in Table 10.

 

 

 

 

 

Table 10.    Lake Roosevelt artificial production life stage survival projections.

 

Rainbow Trout          Artificial Production	No. Eggs @ Initial Culturing	80% Survival to Feeding Fry	90% Survival Fry to Fingerling	90% Survival Distribution to Release as Yearlings
Projected Number Produced:	1,100,000	880,000	792,000	712,800
Kokanee Salmon         Artificial Production	No. Eggs @ Initial Culturing	80% Survival to Feeding Fry	90% Survival  to Fry Release	90% Survival 300,000 Fry Carry Over for Yearling Release
Projected Number Produced:	5,000,000	4,000,000	3,600,000	270,000

 

 

 

 

 

 

Egg Collections and Allotments

 

Kokanee eggs obtained from Meadow Creek and Lake Roosevelt are tested for presence of Infectious Hematopoietic Necrosis, Infectious Pancreatic Necrosis and Viral Hemorrhagic Septicemia viruses.  If samples test positive, eggs from the respective source will be restricted from entering the hatchery facilities. Where samples test negative, WDFW will notarize a Fish Health Certificate for viral negative egg sources.  Kokanee salmon and rainbow trout eyed egg allotments are disinfected before entering the Spokane Tribal Hatchery by submersion in 100 parts per liter Argentine solution for approximately 15 minutes and then rinsed with clean water.

 

Egg Enumeration and Incubator Loading.

 

Either weighted or Von Bayer methods will be used for enumeration of eggs.  Vertical flow incubators and cylindrical upwelling incubators are used for egg incubation.  

 

 

 

Incubation and Hatching

 

The number of days to egg eye-up, hatch and fry emergence, as well as daily water temperature are recorded.  At 90% swim-up fry are released from the upwelling incubators by removing the lids and letting the fry swim out into the raceways.  Mortality rates are recorded throughout the incubation period and swim-up stage.

 

Feeding and Projected Feed Conversions

 

Feed training of kokanee and rainbow trout will begin after full yolk sac absorption.  Feed amount is calculated using bio-mass relative to water temperature and projected growth desires.  Feed conversions are determined by each respective project.  Target feed conversion rate is 1.5 pounds fed per 1 pound of growth.  

 

Raceway Loading

 

Fish are reared relative to a density index less than 0.5 pounds of fish per cubic foot rearing space.

 

Water Quantity Regulation

 

Water inflow required for fish rearing is calculated using respective flow index’s relative to each projects projected lengths and weights using the following formula:

 

                        I =       W                                 where: I   = total inflow

 

                                L x 1.5                                         W = projected weight

 

                                                                                    L = projected length

 

Water Quality & Quantity Monitoring

 

Temperatures and total dissolved gases are monitored to ensure they are within acceptable coldwater fish culturing requirements and to aid in determining feeding amounts and raceway loading rates.  Other parameters monitored as needed or required by each respective project may include pH, conductivity, ammonia, nitrate, nitrite, salinity, and total suspended solids concentration in the hatchery effluent.  The Spokane Tribal Hatchery operates within compliance standards of its Environmental Protection Agency National Pollution Discharge Elimination System permit.  

 

Fish Marking

 

Seasonal workers clip adipose fins on 100% of kokanee (n=300,000) and rainbow trout (n=800,000) prior to release as yearlings.  Kokanee are thermal otolith marked during the egg stage. 

 

 

 

Fish Releases and Inter-Program Transfers

 

Three 1,500 gallon transportation trucks are used for distributing fish. Maximum loading rate of the tanker is 500 pounds of fingerling size fish per haul and 1,500 pounds for yearling or larger size fish. 

 

 

 

Fish Health Management

 

Each hatchery and net pen facilities operate in accordance with the WDFW Fish Health Policy compliance requirements.  Fish health inspections occur prior to fish distribution or as needed for each.  Fish health inspections are performed routinely at Sherman Creek hatchery and some net pen locations. (Table 11).  Fish health inspections are also conducted at the Spokane Tribal Hatchery, but only when an outbreak occurs.  All fish health inspections are performed by a Washington Department of Fish and Wildlife Fish Health Specialist.  All fish are reared under current WDFW fish culture guidelines which include density, flow, feeding and health specifications found in part in US Fish & Wildlife Service, Fish Hatchery Management Manual (Piper, R.G. 1982).

 

 

 

Invasive Species Inspections

 

The Lake Roosevelt Projects are compliant with the WDFW Invasive Species Policy, (see Policy 5310) and are tasked under the Pisces Work Elements to monitor and prevent the spread of invasive species on the projects (http://wdfw.wa.gov/publications/00105/).  Guidelines for invasive species inspections are outlined in Appendix A.

 

 

 

Table 11.    Facility ( SCH = Sherman Creek Hatchery, NP = Net Pens, STH = Spokane Tribal Hatchery), date inspected, species inspected (RB = rainbow trout, KOK = kokanee), stock (SP = Spokane Stock, MC= Meadow Creek, LW = Lake Whatcom, PL = Phalon Lake, LR = Lake Roosevelt Mixed Stock), broodyear, diagnosis (HE= healthy, BKD=bacterial kidney disease, BCD= bacterial coldwater disease, C = columnaris, DS= dropout syndrome, SA=saprolegniasis, BGD= bacterial gill disease, EGD= environmental gill disease, GBD= gas bubble disease, UN= unknown, PB= botulism, CYS= coagulated yolk syndrome, ICH= ichthyobodiasis, and HWT= high water temperature), number of fish in raceway/net pen at time of inspection, percent mortality, size (fish/lb.) at time of inspection, maximum temperature, flow index, density index, and the treatment required at Sherman Creek Hatchery, Spokane Tribal Hatchery, and net pen locations on Lake Roosevelt, WA from 2004-2011.

Facility	Date	Species	Stock	BY	Diagnosis	No. Fish	% Mortality	Fish\Lb.	Max. Temp (F)	Flow Index	Density Index	Treatment
SCH	7/12/2004	RB	SP	2003	HE	94,716	0.01%	50	64	0.5716	0.2017	none
SCH	10/15/2004	RB	SP	2003	HE	83,000	0.00%	15	49	1.0478	0.3945	none
SCH	4/25/2005	KOK	MC	2003	BKD	49,000	0.01%	13	44	0.7606	0.2327	none
SCH	5/12/2005	KOK	MC	2003	BKD	49,000	0.41%	10	55	0.7852	0.2771	none
SCH	6/17/2005	RB	SP	2004	BCD	72,459	0.62%	63	55	0.3748	0.1323	treat w/ TM
SCH	7/6/2005	RB	SP	2004	BCD	70,000	0.15%	45	67	0.3738	0.1599	monitor mortality
SCH	10/3/2005	RB	SP	2004	HE	70,000	0.00%	15	56	0.9426	0.3327	none
SCH	8/28/2006	RB	SP	2005	HE	60,000	0.01%	18	62	0.6439	0.2525	none
SCH	10/6/2006	RB	SP	2005	HE	68,500	0.01%	16	52	0.8114	0.3118	none
SCH	6/4/2007	KOK	LW	2005	HE	70,000	0.02%	13.3	60	0.5963	0.3274	none
SCH	6/22/2007	RB	SP	2006	BCD	138,000	0.30%	100	65	0.3935	0.1852	treat w/ Aquaflor
SCH	7/10/2007	RB	SP	2006	C	138,000	0.10%	65	68	0.4494	0.2468	treat w/ NaCl
SCH	7/10/2007	RB	PL	2007	DS	8,000	6.25%	3,000	68	0.0024	0.1890	treat w/ Aquaflor
SCH	8/8/2007	RB	SP	2006	HE	138,000	0.02%	19	65	1.0204	0.5602	monitor mortality
SCH	10/1/2007	RB	SP	2006	HE	100,728	0.00%	20	48	1.5503	0.3952	none
SCH	10/1/2007	RB	PL	2007	HE	1,600	0.00%	120	48	0.6925	0.2424	none
SCH	5/15/2008	RB	SP	2006	SA	54,000	0.16%	5	47	1.0352	0.5338	treat w/ NaCl Rx
SCH	7/1/2008	RB	SP	2006	BCD	260,480	0.06%	66	68	0.9797	0.4610	treat w/ Aquaflor
SCH	7/22/2008	RB	SP	2006	BGD	260,000	0.06%	50	67	1.1767	0.5538	split fish
SCH	8/29/2008	RB	SP	2007	HE	104,000	0.02%	30	59	0.7731	0.3114	none
SCH	9/25/2008	RB	SP	2007	HE	75,000	0.00%	20.1	51	0.8024	0.2933	none
SCH	5/7/2009	RB	PL	2007	SA	25,000	0.26%	3.8	48	0.6936	0.2968	none
SCH	5/7/2009	KOK	LW	2007	HE	106,000	0.00%	15	48	0.8125	0.4575	none
SCH	7/14/2009	RB	SP	2008	BCD	110,000	0.36%	71	66	0.3941	0.1854	treat w/ Aquaflor
SCH	8/3/2009	RB	SP	2008	ICH & HWT	105,000	1.21%	60	71	0.4591	0.1980	treat w/ formalin
SCH	9/21/2009	RB	SP	2008	HE	102,000	0.00%	34	54	0.6513	0.2809	none
SCH	6/1/2010	KOK	WC	2008	HE	24,500	0.04%	7.5	47	0.3924	0.1679	none
SCH	7/13/2010	RB	SP	2009	HE	110,000	0.02%	70	61	0.4871	0.1872	none
SCH	7/26/2010	RB	SP	2009	BCD	110,000	0.14%	65	68	0.4180	0.1967	treat w/ Aquaflor
SCH	8/3/2010	WS	LR	2010	ECD	800	37.50%	2,500	70	0.0800	0.0064	none
SCH	8/24/2010	RB	SP	2009	BCD	110,000	0.03%	46	59	0.5742	0.2477	treat w/ Aquaflor
SCH	9/3/2010	WS	LR	2010	C	327	3.36%	227	68	0.1295	0.0130	treat w/ TM
SCH	11/5/2010	WS	LR	2010	HE	224	0.00%	19.6	52	0.2469	0.0454	none
SCH	5/25/2011	KOK	LW	2009	HE	69,000	0.01%	11	44	0.7102	0.3662	none
SCH	7/19/2011	RB	SP	2010	HE	100,000	0.04%	60	65	0.4008	0.1886	none
SCH	9/22/2011	RB	SP	2010	HE	100,000	0.01%	24	52	0.7364	0.3474	none
NP	1/10/2005	RB	PL	2004	HE	11,000	0.00%	40	35	N/A	0.0087	none
NP	1/10/2005	RB	SP	2003	HE	12,000	0.00%	10	35	N/A	0.0239	none
NP	4/25/2005	RB	PL	2004	HE	11,000	0.00%	30	44	N/A	0.0105	none
NP	7/6/2005	RB	PL	2004	HE	7,000	1.09%	18	62	N/A	0.0094	none
NP	8/1/2005	RB	PL	2004	HE	7,500	0.20%	12	65	N/A	0.0132	switch feeds
NP	1/23/2006	RB	PL	2005	HE	11,500	0.00%	60	39	N/A	0.0069	none
NP	1/23/2006	RB	SP	2004	HE	10,000	0.00%	8	39	N/A	0.0231	none
NP	3/23/2006	RB	PL	2005	HE	10,900	0.00%	45	46	N/A	0.0080	none
NP	3/23/2006	RB	SP	2004	HE	9,900	0.00%	5.7	46	N/A	0.0287	none
NP	5/22/2006	RB	SP	2004	HE	9,900	0.05%	5	46	N/A	0.0313	none
NP	6/29/2006	RB	PL	2005	GBD	10,000	0.20%	30	60	N/A	0.0096	monitor mortality
NP	7/19/2006	RB	PL	2005	HE	9,500	0.25%	25	68	N/A	0.0103	monitor mortality
NP	1/8/2007	RB	PL	2006	HE	13,700	0.00%	60	36	N/A	0.0083	none
NP	3/21/2007	RB	SP	2005	HE	12,641	0.00%	61	39	N/A	0.0075	none
NP	7/10/2007	RB	PL	2006	UN	12,000	1.67%	17	63	N/A	0.0112	treat w/ TM
NP	1/3/2008	RB	PL	2006	HE	12,775	0.00%	10	34	N/A	0.0170	none
NP	3/19/2008	RB	PL	2006	HE	8,900	0.00%	4	41	N/A	0.0218	none
NP	6/4/2008	RB	PL	2007	GBD	30,000	0.34%	25.4	50	N/A	0.0214	monitor mortality
NP	8/3/2009	RB	PL	2008	HE	9,000	0.08%	14	68	N/A	0.0096	monitor mortality
NP	10/30/2009	RB	SP	2008	PB	10,000	0.30%	20	50	N/A	0.0084	treat w/ TM
NP	1/25/2010	RB	SP	2008	HE	10,000	0.00%	14.2	38	N/A	0.0168	none
NP	3/21/2011	RB	SP	2009	SA	12,000	0.09%	9	39	N/A	0.0274	monitor mortality
STH	3/16/2005	KOK	MC	2003	BKD	24,924	0.24%	12	48	1.5803	0.2756	none
STH	9/7/2005	KOK	MC	2004	BKD	11,091	0.96%	75	62	1.5803	0.2756	none
STH	3/17/2006	RB	SP	2005	BCD	214,000	0.74%	2,000	52	1.5803	0.2756	none
STH	4/12/2007	RB	SP	2006	BCD	102,179	0.18%	500	51	1.5803	0.2756	treat w/ Aquaflor
STH	4/12/2007	KOK	MC	2005	HE	24,408	0.00%	18	48	1.5803	0.2756	none
STH	4/12/2007	KOK	LW	2005	HE	16,725	0.00%	26	48	1.5803	0.2756	none
STH	6/8/2007	RB	SP	2006	BCD	40,000	0.09%	100	60	1.5803	0.2756	treat w/ Aquaflor
STH	2/27/2008	KOK	LW	2005	BKD	23,595	0.04%	28	51	1.5803	0.2756	treat w/ Aquamycin
STH	5/23/2008	RB	SP	2007	BCD	76,018	0.11%	150	54	1.5803	0.2756	treat w/ Aquaflor
STH	7/16/2009	RB	SP	2008	BCD	32,000	0.09%	96	53	1.5803	0.2756	treat w/ Aquaflor
STH	6/24/2010	RB	SP	2009	BCD	59,897	0.04%	383	55	1.5803	0.2756	monitor mortality
STH	9/27/2010	RB	SP	2009	BCD	24,747	0.04%	25	58	1.5803	0.2756	treat w/ Aquaflor
STH	2/9/2011	KOK	LW	2005	BGD	14,000	0.07%	25	51	1.5803	0.2756	treat w/ chloramine-T
STH	3/3/2011	RB	SP	2010	CYS & BCWD	146,365	1.91%	2,026	51	1.5803	0.2756	monitor mortality
STH	5/18/2011	RB	SP	2010	BCD	128,800	0.05%	200	52	1.5803	0.2756	monitor mortality

 

 

Response to ISRP Tailored Questions:

 

7.”Describe opportunities to restore or reintroduce resident native fish: The response indicates that other projects are involved in sturgeon and redband trout restoration and habitat enhancement”.

 

Fisheries management in Lake Roosevelt is a complex matter that requires considerable coordination and we work cooperatively to meet fisheries management and enhancement needs.  There are numerous projects in the region that are designed to meet the management entities’ goals and objectives, including research and monitoring, direct enhancement, protection, and restoration implementation, including artificial production projects, and coordination.

 

 

 

The primary function and goal of the Lake Roosevelt artificial production projects [(Sherman Creek Hatchery (BPA 1991-047-00), Spokane Tribal Hatchery (BPA 1991-046-00), and Lake Roosevelt Development Association Net Pen Project (BPA 1995-009-00)] is to increase recreational and Tribal subsistence harvest opportunities and support development of a localized kokanee stock through egg collection efforts.  These objectives are provided for under the Substitution for Anadromous Fish Losses Policy of the Northwest Power and Conservation Council Fish and Wildlife Program.  The fishing opportunities provided by the hatchery projects secondarily provide restoration and protection of native species through decreased pressure on stressed populations.  Additionally, the Spokane Tribal Hatchery assists with restoration and reintroduction project goals by providing kokanee to support the Colville Confederated Tribe’s efforts to restore kokanee runs in the Sanpoil River. 

 

 

 

In an effort to ensure we make the most of opportunities provided to us by the Northwest Power and Conservation Council Fish and Wildlife Program, Bonneville Power Administration Fish and Wildlife Program, and others, we have worked diligently to ensure that the project tasks are not duplicated by other projects, even while goals and objectives may be similar.  An extraordinary level of cooperation amongst the Lake Roosevelt managers has led to the development of several projects, including those specifically implemented to restore and reintroduce resident native fish including the Lake Roosevelt Sturgeon Recovery Project (BPA 1995-027-00); White Sturgeon Enhancement Project (BPA 2008-116-00), Lake Roosevelt Rainbow Trout Habitat and Passage Improvement Project (BPA 1990-018-00), and Chief Joseph Kokanee Habitat Enhancement Project (BPA 1995-011-00).  These projects were noted and briefly described in the hatchery and net pen proposals that work cooperatively with hatchery projects; however, native species restoration project objectives are outside the hatchery programs scopes.  Complete descriptions of the native species restoration projects can be found in those project proposals.

 

 

 

 

 

8. “Loss assessment: A resident fish loss assessment has not been completed.

 

The four projects that comprise the Lake Roosevelt artificial production program [Sherman Creek Hatchery (BPA 1991-047-00), Spokane Tribal Hatchery (BPA 1991-046-00), Lake Roosevelt Development Association Net Pen Project (BPA 1995-009-00), and the associated monitoring program (Lake Roosevelt Fisheries Evaluation Program, BPA 1994-043-00)] were developed to partially mitigate for the loss of anadromous fish in the blocked region above Chief Joseph and Grand Coulee Dams as defined under the Substitution Policy of the Northwest Power and Conservation Council (NPCC) Fish and Wildlife Program (NPCC 1986, 1987, 1994, 1995, 2000, 2005, 2009).  The loss assessment requirement these projects were linked with was the anadromous fish loss assessment, completed in conjunction with the Fish and Wildlife Program and available in the “Compilation of Salmon and Steelhead Losses in the Columbia River Basin” and the “Numerical Estimates of Hydropower-related Losses” contained in the Council Program (NPCC 1987, 1994, 1995, 2000, 2005) Technical Appendix E.

 

 

 

The Lake Roosevelt fisheries managers feel a resident fish loss assessment is an important component to addressing ongoing resident fish impacts resulting from construction and long-term operation of the hydropower facilities.  We support the implementation of the resident fish loss assessment project proposed by the Colville Confederated Tribes and plan to participate in the loss assessment design and implementation.  We do not, however, feel the resident fish loss assessment is relevant or necessary for continued implementation of projects designed to address anadromous fish losses.

 

 

 

 

 

9. “Impacts of non-native fish releases on native fishes need to be more clearly identified and discussed. The sponsors’ statement that the rainbow trout and kokanee released by the project are "native," may be technically true, but operationally it is not. The rainbow trout are a stock derived from the coastal California subspecies, and the kokanee from Lake Whatcom are from a coastal location in Washington, substantially differentiated from the interior wild fish, namely redband trout, based on recent genetic investigations. The sponsors include an adequate discussion of the operating hypothesis that stocked rainbow trout and kokanee are primarily planktivores. The monitoring plan for the program needs to continue to evaluate the potential for impacts on native kokanee, redband trout, and non-game fish. Impacts to forage fish species could have trophic affects that would require management decisions.”

 

The Lake Roosevelt Artificial Production Program appreciates that the ISRP recognizes the dynamic nature of Lake Roosevelt and the difficulties associated with identifying potential impacts of the artificial program on native species.  The Lake Roosevelt Artificial Production Program stocks rainbow trout and kokanee to increase consumptive and non-consumptive resident fisheries opportunities in the Columbia River above Grand Coulee Dam, as endorsed by the Substitution for Anadromous Fish Losses Policy of the NPCC’s 2009 Fish and Wildlife Program (NPCC 2009).  The production program is partial mitigation for the loss of anadromous fish in the blocked area above Chief Joseph and Grand Coulee dams.

 

Grass-roots efforts to return fishing opportunities to Lake Roosevelt led to the current rainbow trout artificial production program of 750,000 rainbow trout stocked annually into the reservoir.  Concern regarding the impact of hatchery fish on native redband trout within the reservoir and downstream prompted managers to triploid all coastal rainbow trout released into Lake Roosevelt.  The triploidy rates for fish released into the reservoir have been high (81-99%; Table 1), showing the success of this strategy.

 

Project participants appreciate that the ISRP agrees that a greater understanding of impacts to native fish, namely redband trout and forage fish, associated with the artificial production program is needed. Little is currently known about redband trout populations within Lake Roosevelt and its tributaries, although recent genetic investigations have determined there are pure redband stocks in the Upper Columbia River (Small et al. 2005; Taylor 2002; Powell and Faler, 2002, Small et al. 2007, Small et al. 2008).  Improving knowledge about redband trout populations in Lake Roosevelt is key to effectively protecting and enhancing those populations.  To that end, Lake Roosevelt fisheries co-managers have proposed a comprehensive stock assessment of native redband trout in Lake Roosevelt, including examining whether hatchery rainbow and redband trout are found concurrently in spawning areas (under LRFEP 1994-043-00 and JSAP 1997-004-00).  Harvest of redband trout has been documented through the reservoir-wide creel survey that is performed annually.  Redband trout condition factors have remained relatively stable, while harvest has varied from year to year (Table 12).  It is unknown whether the redband population in Lake Roosevelt and the upper Columbia River can withstand the current levels of harvest.  The proposed redband trout assessment will be used to provide critical information that will allow managers to better adaptively manage the redband trout population in Lake Roosevelt and its tributaries.

 

 

 

Table 12.    Harvest rates and condition factor (SD) for redband trout from 2007 through 2010 from Lake Roosevelt, WA.  (2010 data is preliminary)

Year	Harvest	KTL
2007	4,920	1.04 (0.15)
2008	2,538	1.08 (0.17)
2009	2,233	1.10 (0.22)
2010*	3,392	1.05 (0.14)

 

 

 

 

Concern regarding potential impacts of predation on native species by the coastal stock of rainbow trout released into the reservoir is unfounded.  Spatial separation exists between rainbow trout and kokanee in Lake Roosevelt, thus reducing the probability of kokanee predation by stocked trout.  Limnetic, vertical fish distribution data collected by Washington Department of Fish and Wildlife from 2001-2003 indicated that rainbow trout and kokanee salmon had limited spatial overlap (Baldwin et al, 2006; Baldwin and Woller 2006), which reduces the potential of rainbow trout and kokanee salmon interactions.

 

Zooplankton has long been recognized as the primary food resource for non-piscivorous fishes in Lake Roosevelt.  During early investigations of trophic status in Lake Roosevelt, Jagielo (1984) examined zooplankton availability as a limiting factor for kokanee, and determined that zooplankton abundance was sufficient to support a much larger kokanee population than existed in the reservoir.  The LRFEP monitors hatchery production effects on the trophic structure of the reservoir.  Recent zooplankton monitoring in Lake Roosevelt suggest ample zooplankton abundance is present to support kokanee and rainbow trout populations (Cichosz et al. 1999; Miller et al. 2011).  Although rainbow trout and kokanee stocking has occurred annually for several years, zooplankton production in Lake Roosevelt appears to be more susceptible to water retention time associated with hydro-operations than predation by planktivores (Figure 4).

 

 

 

 

 

 

 

Figure 4.     Annual mean zooplankton biomass(µg/m3) from 1998 through 2008 (represented by the yellow bars), and annual mean water retention time (represented by the pink line) for Lake Roosevelt, WA.

 

 

 

 

Hatchery rainbow trout released into Lake Roosevelt are facultative planktivores, deriving 67-80% of their organic carbon from zooplankton (Black et al 2003).  Furthermore, diet data has been collected for over 15 years in Lake Roosevelt and has shown that rainbow trout are primarily zooplanktivorous in Lake Roosevelt (Cichosz et al. 1997; Griffith et al. 1995; Lee et al. 2006).  Diet data indicated that zooplankton, primarily large sized Daphnia, were the primary food source for rainbow trout in Lake Roosevelt (Ria value of 57.8% Daphnia; Lee et al. 2006), whereas fish (Cottids, Centrarchids, Percids, Salmonids and unidentified fish) comprised only 4.6% (Ria value; Lee et al. 2006).  Evidence for limited piscivory in rainbow trout, and on salmonids in particular, is emphasized in the diet data from 2000 through 2004 (Table 13), which shows that Salmonidae have been identified in the stomach contents of only one rainbow trout from a total of 613 stomachs (Table 13).  This is most likely due to their maturation timing (mature at age 3) and relatively small terminal growth length (maximum, 600 mm).  This is in direct contrast to Lake Pend Oreille, where the rainbow are large pelagic predators, long lived, and large bodied.  While both are rainbow trout, the Spokane stock in Lake Roosevelt does not exhibit the same foraging and life history patterns akin to Gerrard rainbow trout in Lake Pend Oreille.

 

 

 

Table 13.    Relative importance (Ria) values of diet items from hatchery rainbow trout collected by boat electrofishing at Lake Roosevelt, WA (2000-2004).

 

 

Year	2000	2001	2002	2003	2004
# Fish Sampled	n = 43	n = 58	n = 212	n = 112	n = 188
Diet Category	Ria	Ria	Ria	Ria	Ria
Zooplankton	46.89	45.36	45.52	55.16	57.78
Insects	24.61	28.92	28.50	13.79	3.97
Non-salmonids	0.00	0.51	0.86	0.59	1.09
Salmonidae	0.00	0.00	0.00	0.00	0.20
Unidentified fish	1.25	0.88	0.13	0.26	3.35
Other	27.24	24.32	25.00	30.20	33.61
Grand Total	100.00	100.00	100.00	100.00	100.00

 

 

The Lake Roosevelt managers have determined that while ISRP concerns on potential impacts by rainbow trout predation exist elsewhere, predation on kokanee by rainbow trout does not appear to be an issue in the Lake Roosevelt ecosystem.  Based on limited piscivory seen for rainbow trout in the reservoir, the short time fish are in the fishery, the stock used (Spokane stock; derived from McCloud River), and the clear benefits to anglers, managers believe rainbow trout production will not negatively impact kokanee and redband trout survival and will benefit the Lake Roosevelt fishery.

 

Kokanee stocks currently released into Lake Roosevelt are from two sources, a Lake Whatcom coastal stock and a stock from Meadow Creek, a tributary of Lake Kootenay, British Columbia.  Managers have identified Meadow Creek as the preferred stock for supplementation because it consistently out-performs the coastal strain.  However, due to the unreliability of Meadow Creek egg availability, Lake Whatcom stock will remain a part of the Lake Roosevelt kokanee artificial production program.  Regardless of which stock is used, managers and researchers do not believe that supplementation of kokanee negatively impact native kokanee stocks in the reservoir.  Low abundances exhibited by Lake Roosevelt (upper Columbia River) wild kokanee are of concern, particularly in light of higher exploitation rates observed in the creel where wild kokanee harvest comprised more than 50% of the total harvest (Lee et al. 2010; Miller et al. 2011).  In order to protect wild kokanee in the reservoir, the Lake Roosevelt fisheries managers implemented protective kokanee harvest regulations, limiting the number of kokanee with intact adipose fins that can be harvested (WDFW 2011).  Based on current status of wild kokanee in the reservoir, managers continue to recommend and support kokanee enhancement through the artificial production program in order to protect the native stock, and to allow restoration of tributary stocks to be implemented in light of limited abundances of wild kokanee.

 

We recognize the importance of monitoring native fish populations to identify potential impacts associated with artificial production activities.  Thus, native fish assessments and monitoring is conducted as part of the monitoring and evaluation program (LRFEP 1994-043-00).  Managers strongly support the continuation of the rainbow trout and kokanee production programs, and believe they greatly enhance Lake Roosevelt fishing opportunitie 

 

The Lake Roosevelt managers have determined that while ISRP concerns on potential impacts by rainbow trout predation exist elsewhere, predation on kokanee by rainbow trout does not appear to be an issue in the Lake Roosevelt ecosystem.  Based on limited piscivory seen for rainbow trout in the reservoir, the short time fish are in the fishery, the stock used (Spokane stock; derived from McCloud River), and the clear benefits to anglers, managers believe rainbow trout production will not negatively impact kokanee and redband trout survival and will benefit the Lake Roosevelt fishery.

 

Kokanee stocks currently released into Lake Roosevelt are from two sources, a Lake Whatcom coastal stock and a stock from Meadow Creek, a tributary of Lake Kootenay, British Columbia.  Managers have identified Meadow Creek as the preferred stock for supplementation because it consistently out-performs the coastal strain.  However, due to the unreliability of Meadow Creek egg availability, Lake Whatcom stock will remain a part of the Lake Roosevelt kokanee artificial production program.  Regardless of which stock is used, managers and researchers do not believe that supplementation of kokanee negatively impact native kokanee stocks in the reservoir.  Low abundances exhibited by Lake Roosevelt (upper Columbia River) wild kokanee are of concern, particularly in light of higher exploitation rates observed in the creel where wild kokanee harvest comprised more than 50% of the total harvest (Lee et al. 2010; Miller et al. 2011).  In order to protect wild kokanee in the reservoir, the Lake Roosevelt fisheries managers implemented protective kokanee harvest regulations, limiting the number of kokanee with intact adipose fins that can be harvested (WDFW 2011).  Based on current status of wild kokanee in the reservoir, managers continue to recommend and support kokanee enhancement through the artificial production program in order to protect the native stock, and to allow restoration of tributary stocks to be implemented in light of limited abundances of wild kokanee.

 

We recognize the importance of monitoring native fish populations to identify potential impacts associated with artificial production activities.  Thus, native fish assessments and monitoring is conducted as part of the monitoring and evaluation program (LRFEP 1994-043-00).  Managers strongly support the continuation of the rainbow trout and kokanee production programs, and believe they greatly enhance Lake Roosevelt fishing opportunities.