This project began in 1986 with the title Status and Habitat Requirements of White Sturgeon Populations in the Columbia River Downstream from McNary Dam.  The title has since changed, but the project number (198605000) has not.  The project was based partly on findings and recommendations from the White Sturgeon Research Needs Workshop held in 1983 (Fickeisen et al. 1984).  As the original title indicates, the early focus of the study was to provide information on the status of white sturgeon populations in the lower Columbia River.  Objectives were to (1) describe reproduction and early life history characteristics of white sturgeon populations, (2) describe the life history and population dynamics of subadult and adult white sturgeon, (3) define habitat requirements for spawning and rearing of white sturgeon and quantify extent of habitat available, and (4) evaluate the need and identify potential methods for protecting, mitigating, and restoring white sturgeon populations. 

The Bonneville Power Administration (BPA) contracted with ODFW to conduct the study, and ODFW subsequently entered into cooperative agreements with the Washington Department of Fish and Wildlife (WDFW), what is now the U.S. Geological Survey (USGS), and the NMFS, now NOAA Fisheries, to conduct portions of the study.  In general, Objectives 1 and 3 were addressed by USGS and NMFS, whereas Objectives 2 and 4 were addressed by ODFW and WDFW.

From 1986-88 methodologies were developed for habitat mapping and modeling, capture gears for various life stages, and marking and aging techniques.  By 1992, findings included (1) dams limit movements of white sturgeon and have functionally isolated populations in mainstem Columbia River reservoirs; (2) population dynamics of white sturgeon are unique in each reservoir; (3) population productivity is 10-100 times higher downstream from Bonneville Dam than in Bonneville, The Dalles, or John Day reservoirs; (4) discharge influences spawning habitat for white sturgeon; (5) reservoirs provide large areas of suitable physical habitat for juvenile and adult white sturgeon, but compensatory population responses may reduce productivity if carrying capacity is exceeded; and (6) over-fishing had occurred in Bonneville, The Dalles, and John Day reservoirs.  Appropriate exploitation rates under the reduced productivity resulting from the development and operation of the hydrosystem were described.

Based on these conclusions, recommendations were developed to guide all future work to be conducted as part of this project: (1) intensify management of fisheries for impounded populations, (2) evaluate if augmented river discharge in May and June improves spawning and recruitment, (3) evaluate the feasibility of enhancing depleted populations by transplanting juvenile white sturgeon from populations downstream from Bonneville Dam, (4) identify habitat requirements of subadult and adult white sturgeon, quantify amounts of suitable habitat, and evaluate constraints on enhancement, (5) refine and evaluate hatchery technology for enhancement of threatened populations of white sturgeon, and (6) investigate the need and potential measures for protecting and enhancing populations upstream from McNary Dam.

Work from 1993-97 focused on developing and implementing the mitigation actions recommended, monitoring the effects of these actions, and conducting the research activities recommended.  To reflect this change in direction, the title of the project changed to Effects of Mitigative Measures on Productivity of White Sturgeon Populations in the Columbia River Downstream From Bonneville Dam, and Status and Habitat Requirements of White Sturgeon Populations in the Columbia and Snake Rivers Upstream From McNary Dam.  With this new phase of the project, the U.S. Fish and Wildlife Service (USFWS) and the Columbia River Inter-Tribal Fish Commission (CRITFC) joined as cooperators.  From 1993-97 ODFW addressed recommendations 1, 3, 4, and 6; WDFW addressed recommendations 1, 2, 3, and 6; USFWS addressed recommendation 4; NMFS addressed recommendations 1 and 4; USGS addressed recommendations 2, 3, and 4, and CRITFC addressed recommendation 1.  NMFS completed their work in 1997 and ended their status as project cooperators.

The CRITFC participated in white sturgeon disease investigations and fin clip research from 1995-1997.  The CRITFC involvement with the current project is complementary and cooperative to OFDW and WDFW lead components.  The CRITFC’s primary role is to capture, mark/tag and release white sturgeon for population abundance metrics.  The CRITFC is the lead agency in administering tribal subcontracts for marking/tagging thousands of sturgeon each winter since incorporation of tribal efforts in 1997.  These activities provide an important base of marked fish prior to the start of the coordinated summer recapture effort.  The additional marks provide a higher degree of confidence during statistical analyses of the population assessment.  Winter tagging work is performed in one reservoir per year, rotating among the three Zone 6 reservoirs between Bonneville and McNary dams.  In addition, the CRITFC provides technical support to ODFW on recruitment to age-0 assessments and to WDFW on commercial fishery assessments. All work efforts for marking/tagging, age-0 recruitment indexing, and commercial sampling are conducted annually and seasonally in coordination with ODFW and WDFW.  Assessing the commercial and subsistence fisheries is done annually to monitor and ensure that guidelines for each reservoir population are followed. 

By 1998 much of the recommended work had been completed or was well underway.  Accomplishments grouped by applicable recommendation included:

Recommendation (1) - Intensify management of fisheries for impounded populations:

• Demonstrated increased abundance of white sturgeon in The Dalles and John Day reservoirs, which was attributable to intensive harvest management and reduced exploitation (Table 1);
• Intensive fishery management had become an ongoing component of the project.

Recommendation (2) - Evaluate if augmented river discharge in May and June improves spawning and recruitment:

• Developed two indices of relative abundance for age-0 white sturgeon (summary of data collected to date for one index, proportion of positive efforts, is shown in Table 2 and Figure 4);
• Determined that white sturgeon larvae are susceptible to gas bubble trauma in laboratory experiments;
• Determined that hydropeaking at The Dalles Dam displaces white sturgeon eggs and larvae from incubation areas;
• Provided broad recommendation for flows to provide spawning habitat.

Recommendation (3) - Evaluate the feasibility of enhancing depleted populations by transplanting juvenile white sturgeon from populations downstream from Bonneville Dam:

• Found that white sturgeon transplanted to The Dalles Reservoir demonstrated excellent survival and growth one and two years later (Rien and North 2002).

Recommendation (4) - Identify habitat requirements of subadult and adult white sturgeon, quantify amounts of suitable habitat, and evaluate constraints on enhancement:

• Determined habitats used by spawning and rearing fish;
• Developed habitat maps and flow-habitat models for the Columbia River up to Priest Rapids Dam;
• Provided broad recommendation for flows to provide spawning habitat.

Recommendation (5) - Refine and evaluate hatchery technology for enhancement of threatened populations of white sturgeon:

• No work implemented by 1998.

Recommendation (6) - Investigate the need and potential measures for protecting and enhancing populations upstream from McNary Dam:

• Completed initial population estimates for white sturgeon in McNary, Ice Harbor, Little Goose, and Lower Monumental reservoirs, and the Hanford Reach.

Because much of the recommended work had been completed, a new phase of the project was started.  In this phase, from 1998-2002, mitigation actions resulting from recommendations 1 and 3 were fully implemented, investigations resulting from recommendations 2, 4 and 6 were completed, and work to address recommendation 5 began.  The title of the project changed once again to White Sturgeon Mitigation and Restoration in the Columbia and Snake Rivers Upstream from Bonneville Dam.  Oregon State University (OSU) joined the project in 2000 to develop a maturation status model as part of recommendation (1).

Accomplishments from 1998-2002 included: 

Recommendation (1):

• Maintained increase in abundance of white sturgeon in The Dalles and John Day reservoirs, which again was attributable to intensive harvest management and reduced exploitation;
• Intensive fishery management continued as ongoing component of the project;
• Developed a preliminary discriminant function analysis model to predict white sturgeon sex and stage of maturity using blood plasma indicators, sex steroids and calcium, and fork length. 

Recommendation (2):

• Conducted yearly age-0 white sturgeon indexing (trawling) in Bonneville, The Dalles, and John Day reservoirs to describe environmental influences on recruitment.
• Implemented sampling with gillnets in The Dalles, John Day, McNary, Ice Harbor,  and Little Goose reservoirs as an alternate method to index recruitment to age-0.
• Examined movements and behavior of pre-spawn and spawning white sturgeon in The Dalles Reservoir in relation to dam operations.

Recommendation (3):

• Annual transplants of white sturgeon from below Bonneville Dam to The Dalles and John Day reservoirs became an ongoing component of project (Table 3).

Recommendation (4):

• Examined seasonal habitat use and movements of sub-adult and adult white sturgeon in a free-flowing and impounded reach of the Columbia River.
• Quantified habitat suitable for spawning and rearing of white sturgeon in the Columbia and the Snake rivers in relation to yearly flows and temperatures (Figure 1).
• Described the effects of proposed reservoir water level manipulations on productivity of white sturgeon.
• Assessed the effects of water temperature on the development of white sturgeon eggs. 
• Described the food habits of first-feeding larvae and age-0 white sturgeon.
• Investigated size vulnerability of white sturgeon larvae and juveniles to predation, and effects of turbidity levels on predator-prey interactions.

Recommendation (5):

• Initiated work to evaluate the feasibility of using hatchery-reared white sturgeon to supplement depressed populations.  The first research-level release of hatchery-reared fish into the Columbia River occurred in 2002 (Table 5).
• CRITFC conducted four years of broodstock capture, holding and spawning efforts at the Abernathy Fish Technology Center and a satellite spawning facility at McNary Dam.  In years with unsuccessful spawning, fish were purchased from a licensed private facility to augment the program.  These efforts were noteworthy, since it involved surgical verification of mature adult sturgeon, gamete analysis, hormone injections, egg and milt collection, fertilization, incubation, rearing, marking and tagging, transport and release.  These efforts provided key information regarding the viability of using previously demonstrated methodologies and adapting them for wild broodstock taken prior to the spawning period, an important consideration when working with smaller depressed populations upstream of McNary Dam.

Recommendation (6):

• Completed index sampling to develop initial descriptions of white sturgeon populations in Rock Island Reservoir, Lake Rufus Woods, and Lake Roosevelt.

Accomplishments from the 2003-09 phase of this project included:

Recommendation (1):

• Continued intensive fishery management.  Although abundance of white sturgeon in reservoirs remains higher than prior to intensive harvest management and reduced exploitation, results indicate that regular monitoring is required to preclude over-exploitation and insufficient escapement of sturgeon into the broodstock population.  Since 2003, Bonneville, The Dalles, and John Day reservoirs have each been monitored every 3 years, rather than every 5 years as before 2003.  
• Refined population dynamics models to incorporate new information on individual fish growth.  Large numbers of recaptures of tagged fish have allowed us to calculate individual fish growth directly, rather than inferring growth from length-at-age models and aging information.  Results indicate that length-at-age models underestimated age, and overestimated growth rate (Figure 2).
• Continued to refine white sturgeon growth information from recaptures of previously PIT tagged white sturgeon, results support the assertion that length-at-age models underestimated age, and overestimated growth rate (Figure 3).
• Continued to assess the reproductive structure and spawning periodicity of white sturgeon in the Lower Columbia River.  These deliverables provide valuable information that may be used in the recovery of white sturgeon populations.  One goal of many recovery programs for endangered or threatened sturgeon includes the recovery of a population to 50 to 500 individuals.  Recovering a population to a target number, while very useful to avoid inbreeding depression, does not take into consideration the ability of the population to reproduce, i.e. the reproductive health of the population.  Recovering a threatened or endangered population of sturgeon to a target number of adults and a reproductive structure that may allow for a sustainable population will not only reflect healthy ecosystem function but move recovery in the right direction. 
• Further work to refine the maturation status model.  Over 80% of fish were correctly classified into two groups of sex (female or male) or four groups of sex and stage of maturity (immature female, immature male, maturing female, maturing male).  Though error does exist in the classification of sex and stage of maturity of white sturgeon, the technique using blood plasma indicators currently has significant advantages over the more invasive biopsy method.  Work is also proceeding on the development of a non-invasive test using mucus and/or urine to discriminate sex and stage of maturity in white sturgeon.  Additional work is needed to help classify spawning periodicity and maturation cycles in wild white sturgeon.

Recommendations (2) and (4):

• Continued annual monitoring of age-0 white sturgeon to develop a long-term database to evaluate relationships between hydropower system operations and recruitment to age-0 and older.  Over the recent history of the project, river flows have not shown sufficient annual variability to allow adequate correlations between relative abundance of age-0 sturgeon and hydrosystem operations.

Recommendation (3):

• Annual transplants of fish into The Dalles and John Day reservoirs continued through 2005 (Table 3). Effects of transplanting juvenile white sturgeon into The Dalles Reservoir was assessed in 2002 and 2005.  Population sampling in The Dalles Reservoir in 2005 indicated that transplanted sturgeon made up approximately 4% of total catch during summer setline sampling.  Effects of supplementation into John Day Reservoir were evaluated in 2001 and 2004.  During summer setline sampling in John Day Reservoir, approximately 5% of total catch was comprised of transplanted fish.  Transplant supplementation was discontinued after the 2005 effort.
• Transplanted fish from early releases are becoming large enough to contribute to fisheries.  Since 1998 in The Dalles Reservoir fish transplanted in 1994 and 1995 have contributed between 1 and 9% to the annual commercial harvest (Figure 5), and modeling efforts indicate that approximately 100 fish from these initial transplant groups will recruit to the broodstock population.

Recommendation (5):

• Continued work to refine and evaluate hatchery technology.   We were able to release 12,000 age-0 fish before cancellation of this portion of the program, and another 8,600 yearlings following cancellation.  All of these fish were released into Rock Island Reservoir.  Field sampling to update growth and movement of these fish in the release reservoir and one downstream reservoir was conducted in the winter of 2006.  Over 40,000 additional fry reared by this program were released into the Willamette River, Oregon, following program cancellation.  These fish were too small to effectively mark for release into the research area.
• Previous efforts by the Columbia River Inter-Tribal Fish Commission (CRITFC) in artificial propagation research have provided information regarding the movement and growth of hatchery reared sturgeon at large in the Columbia River.  These efforts are important in considering supplementation measures to ensure that the populations of white sturgeon in Bonneville, The Dalles and John Day reservoirs are managed with respect to the relative abundances in each reservoir. Productivity and recruitment are highly variable, in part due to the impacts of hydropower system operation on essential white sturgeon habitat and rearing elements.  Recapture data for hatchery reared white sturgeon has accumulated from various stock assessments since the releases in the mid 2000’s.
• Releases of hatchery reared sturgeon in Rock Island Reservoir in 2003 and in John Day Reservoir in 2002 and 2005 have provided the basis for evaluation of these fish when sufficient numbers were recaptured over time in periodic stock assessments (Table 5).

Table 1.  Abundance estimates for Zone 6 reservoirs and the Hanford Reach of McNary Reservoir, 1987 – 2008.

^a Hanford Reach and McNary Reservoir = 45,500 acres; Bonneville Reservoir = 20,800 acres; The Dalles Reservoir = 11,100 acres;  John Day Reservoir = 51,900 acres.

^b Confidence intervals for these estimates are not provided because they are derived from expansion, not directly calculated from mark-recapture data.

^c Total poundage is estimated by multiplying total abundance (133,200) by median weight (5.0 kg or 11.02 lbs) of sturgeon caught with setlines in sampling periods 2 – 4.

Table 2.  Proportion of trawl tows (italics) and gill-net sets (bold) that captured age-0 white sturgeon (Ep) in several Snake and Columbia river reservoirs, 1989 - 2009.  A “-“ indicates sampling was not conducted.

Table 3.  Number of white sturgeon transported from below Bonneville Dam to The Dalles and John Day reservoirs from 1994 – 2005.

Figure 1.  Annual mean composite indices of spawning habitat (temperature conditioned weighted usable area (WUA)) for white sturgeon for each of the four dam tailraces that have been modeled (Parsley and Beckman 1994).  Note that the scale differs on the Y-axis among graphs.  Excerpted from Parsley and Kofoot 2008.

Figure 2.  Relationship between annual growth rate derived from length-at-age analysis (solid lines) and annual growth rate measured from individual recaptured white sturgeon (dotted line) for white sturgeon from Columbia River reservoirs.

Figure 3.  Annual growth rates of white sturgeon in Zone 6 reservoirs.  The vertical bars represent the size range of legally harvestable sturgeon in Bonneville Reservoir.

Figure 4.  Recruitment index for white sturgeon (proportion of sets capturing one or more young-of-year fish) in Bonneville, The Dalles, and John Day reservoirs, and average daily flow at McNary Dam (April-July).  The Bonneville index is based on standardized trawl efforts 1989-2004.  The Dalles and John Day indexes are based on standardized gill-net effort initiated in 1997. 

Figure 5.  Estimated number of PIT-tagged Trawl & Haul transplants harvested annually in The Dalles Reservoir commercial fishery, 1998-2008 (n=287). Percent annual contribution to commercial fishery is shown above bars.

Summary of Major Monitoring, Evaluation and Research Results

A review of the previous sections can be summarized as follows:

From 1986-88 we:

• Developed methodologies for habitat mapping and modeling, capture gears for various life stages, and marking and aging techniques.

By 1992 we:

• Determined that dams limit movements of white sturgeon and have functionally isolated populations in mainstem Columbia River reservoirs;
• Described population dynamics and found them to be unique in each reservoir;
• Found population productivity to be 10-100 times higher downstream from Bonneville Dam than in Bonneville, The Dalles, or John Day reservoirs;
• Identified reduced flows and subsequent poor recruitment as a potential factor limiting white sturgeon productivity in impoundments; 
• Determined reservoirs provide large areas of suitable habitat for juvenile and adult white sturgeon, but compensatory population responses may reduce productivity if carrying capacity is exceeded;
• Determined over-fishing had occurred in Bonneville, The Dalles, and John Day reservoirs, and described appropriate exploitation rates under the reduced productivity resulting from the development and operation of the hydrosystem.

By 1998 we:

• Demonstrated increased abundance of white sturgeon in The Dalles and John Day reservoirs, which was attributable to intensive harvest management and reduced exploitation;
• Developed two indices of relative abundance for age-0 white sturgeon;
• Determined that white sturgeon larvae are susceptible to gas bubble trauma in laboratory experiments;
• Determined that hydropeaking at The Dalles Dam displaces white sturgeon eggs and larvae from incubation areas;
• Provided a broad recommendation for flows to provide spawning habitat;
• Found that white sturgeon transplanted to The Dalles Reservoir demonstrated excellent survival and growth one and two years later;
• Developed habitat maps and flow-habitat models for the Columbia River up to Priest Rapids Dam;
• Completed initial population estimates for white sturgeon in McNary, Ice Harbor, Little Goose, and Lower Monumental reservoirs, and the Hanford Reach.

By 2002 we,

• Maintained increases in abundance of white sturgeon in The Dalles and John Day reservoirs, which again was attributable to intensive harvest management and reduced exploitation;
• Developed a discriminant function analysis model to predict white sturgeon sex and stage of maturity based on blood plasma indicators, sex steroids and calcium, and fork length; 
• Implemented an annual sampling program to index relative abundance for age-0 white sturgeon;
• Included annual transplants of white sturgeon from below Bonneville Dam to The Dalles and John Day reservoirs as an ongoing component of the project;
• Initiated work to evaluate the feasibility of using hatchery-reared white sturgeon to supplement depressed populations;
• Completed index sampling to develop initial descriptions of white sturgeon populations in Rock Island Reservoir, Lake Rufus Woods, and Lake Roosevelt.

From 2003 to 2005 we,

• Continued intensive harvest management of Bonneville, The Dalles, and John Day reservoirs.
• Investigated individual fish growth in Bonneville, The Dalles, and John Day reservoirs.
• Developed a non-invasive method for determining sex of white sturgeon and began work to describe maturational status and reproductive potential of white sturgeon in impounded and unimpounded reaches.
• Documented predation on juvenile white sturgeon up to 120 mm by resident fish predators in laboratory experiments.  Water turbidity was found to influence predation. 
• Continued annual sampling to index relative abundance of age-0 white sturgeon in Columbia and Snake River reservoirs.
• Continued annual transplants of juvenile white sturgeon from below Bonneville Dam to The Dalles and John Day reservoirs to supplement populations with depressed reproduction.
• Released hatchery reared sturgeon in three separate events in John Day Reservoir in the 2000’s.
• Following elimination of the hatchery component of this program, completed releases of remaining hatchery white sturgeon being reared at the USFWS Abernathy facility.

From 2006 to 2009 we,

• Continued intensive harvest management of Bonneville, The Dalles, and John Day reservoirs.
• Continued to investigate and refined estimates of individual fish growth in Bonneville, The Dalles, and John Day reservoirs.
• Described maturational status and reproductive potential of white sturgeon in unimpounded reaches.
• Continued to investigate maturational status and reproductive potential of white sturgeon in impounded reaches
• Continued annual sampling to index relative abundance of age-0 white sturgeon in Columbia River reservoirs
• Following the discontinuation of the transplant supplementation component of the program, we monitored survival, growth, and contribution to fisheries of transplanted fish.

Fishery Management Specific Activities, Results and Accomplishments

Past and proposed work associated with intensive monitoring of harvest, together with population monitoring, is necessary to maintain fisheries effort and harvest at sustainable levels while building population productivity.  These activities address biological objective (3)  for the Columbia River Gorge, Lower Middle Columbia River, and Lower Snake River subbasins: “to restore and ensure sustainable fisheries”.

The deliverables associated with intensive fishery management and harvest monitoring are: (1) in-season estimates of recreational fishery and commercial fishery harvest to ensure that harvest is maintained at sustainable levels and (2) development of annual population assessments and estimates of sustainable harvest levels to inform establishment of annual harvest guidelines by the state/Tribal Sturgeon Management Task Force.  The products necessary for developing deliverable (1) include weekly summaries of observed effort, catch rate, and harvest by boat and bank anglers in each reservoir and monthly and seasonal estimates of harvest.  The products necessary for developing deliverable (2) include results from modeling projected population growth based on reservoir specific population age structure, survival, and sustainable harvest rates.

Intensive harvest management and reduced exploitation has contributed to increased abundance of white sturgeon in all three reservoirs (Table 1).  Annual white sturgeon harvest, relative to sustainable harvest guidelines, and recreational season length (January to closing date) is provided in Table 4.

Table 4.  Annual reservoir specific recreational and commercial fishery white sturgeon harvest guidelines and annual harvest estimates for Bonneville, The Dalles, and John Day reservoirs, 1996-2010.

Table 5.  Numbers and release locations of hatchery reared white sturgeon in the Columbia and Willamette rivers from 2002 to 2005.

Regional Coordination Accomplishments

Project personnel annually coordinates with, provides data to, and advises the Sturgeon Management Task Force (SMTF).  The SMTF operates under the auspices of US v Oregon and is the regional umbrella group for managing fisheries in the impounded Columbia River between Bonneville and McNary dams.

In addition to ensuring that all white sturgeon work in the Columbia River Basin is coordinated and complimentary, project personnel regularly organize, or participate in comprehensive meetings to discuss issues and share findings.  In December 1997, the Oregon Department of Fish and Wildlife (ODFW) organized a meeting consisting of (1) a white sturgeon genetics roundtable, and (2) a white sturgeon summit meeting.  In 2000, the Nez Perce Tribe organized and hosted a white sturgeon research coordination meeting.  Another meeting in Vancouver, Washington, concentrating on genetics and disease issues, as well as updates of ongoing projects, was hosted by the Columbia River Inter-Tribal Fish Commission (CRITFC) and the Washington Department of Fish and Wildlife (WDFW) in August 2002.  In 2004 and 2005 project cooperators participated in a biological review team for the Nez Perce Tribe’s White Sturgeon Management Plan.  In 2006, project cooperators participated in the White Sturgeon Summit, sponsored by the Columbia Basin Fish and Wildlife Authority (CBFWA) and held in Spokane, WA.  The summit’s theme was “White Sturgeon in the Columbia River Basin: Research, Management, and Restoration,” and included researchers and fishery managers from across the Columbia River Basin.  Likewise, the CRITFC hosted a 2-day white sturgeon regional strategic planning workshop held December 1-2, 2009 in Boardman, OR, as part of their hatchery master planning process.  This strategic planning workshop involved identifying regional priorities and research needs for white sturgeon.  Finally, project personnel participated on technical committees responsible for guiding the development of white sturgeon management plans for Grant PUD and Chelan PUD.  These two plans address the need for restoration of white sturgeon populations in Priest Rapids, Wanapum, and Rocky Reach reservoirs on the Columbia River.

Such periodic regional meetings are expected to occur in the future, with consideration given to producing formal proceedings and to foster effective regional information sharing, as recommended in a review by the Independent Scientific Review Panel in 2002.