White Sturgeon (Acipenser transmontanus): amended recovery strategy 2023

Official title:  Amended recovery strategy for White Sturgeon (Acipenser transmontanus) in Canada [Final]

On this page

• Preface
• Acknowledgements
• Executive summary
• 1. Species information
• 2. Description of the species
• 3. Description of needs of the species
• 4. Threats
• 5. Habitat trends
• 6. Knowledge gaps
• 7. Recovery
• 8. Critical habitat
• 9. Basin overview for each recovery population
• 10. Implementation
• 11. Activities permitted by the recovery strategy
• 12. References cited
• Appendix A: studies to address identified knowledge gaps for white sturgeon
• Appendix B: recovery of middle and lower fraser river white sturgeon populations and important habitats
• Appendix C: acronyms used in the recovery strategy
• Appendix D: glossary of terms
• Appendix E: record of consultation and cooperation

About the Species at Risk Act recovery strategy series

What is the Species at Risk Act (SARA)?

SARA is the Act developed by the federal government as a key contribution to the common national effort to protect and conserve species at risk in Canada. SARA came into force in 2003 and one of its purposes is “to provide for the recovery of wildlife species that are extirpated, endangered or threatened as a result of human activity.”

What is recovery?

In the context of species at risk conservation, recovery is the process by which the decline of an endangered, threatened, or extirpated species is arrested or reversed and threats are removed or reduced to improve the likelihood of the species’ persistence in the wild. A species will be considered recovered when its long-term persistence in the wild has been secured.

What is a recovery strategy?

A recovery strategy is a planning document that identifies what needs to be done to arrest or reverse the decline of a species. It sets goals and objectives and identifies the main areas of activities to be undertaken. Detailed planning is done at the action plan stage.

Recovery strategy development is a commitment of all provinces and territories and of three federal agencies — Environment Canada, Parks Canada Agency, and Fisheries and Oceans Canada — under the Accord for the Protection of Species at Risk. Sections 37–46 of SARA outline both the required content and the process for developing recovery strategies published in this series.

Depending on the status of the species and when it was assessed, a recovery strategy has to be developed within one to two years after the species is added to the List of Wildlife Species at Risk. Three to four years is allowed for those species that were automatically listed when SARA came into force.

What’s next?

In most cases, one or more action plans will be developed to define and guide implementation of the recovery strategy. Nevertheless, directions set in the recovery strategy are sufficient to begin involving communities, land and water users, and conservationists in recovery implementation.

The series

This series presents the recovery strategies prepared or adopted by the federal government under SARA. New documents will be added regularly as species get listed and as strategies are updated.

To learn more

To learn more about the Species at Risk Act and recovery initiatives, please consult the SARA Public Registry.

Preface

The white sturgeon is a freshwater fish, with six populations in Canada (Lower Fraser River, Mid Fraser River, Nechako River, Upper Fraser River, Upper Columbia River, and Kootenay River). All populations are managed by the British Columbia (B.C.) Ministry of Environment (MOE), while four SARA-listed populations are under the responsibility of the federal government. The Species at Risk Act (SARA, Section 37) requires the competent minister to prepare recovery strategies for listed Extirpated, Endangered and Threatened species. Four populations of white sturgeon (Nechako River, Upper Fraser River, Upper Columbia River, and Kootenay River) were listed as Endangered under SARA in August 2006. The development of this recovery strategy was led by Fisheries and Oceans Canada (DFO) – Pacific Region and the B.C. MOE in cooperation and consultation with Parks Canada, many individuals, organizations and government agencies, as indicated below. The strategy meets SARA requirements in terms of content and process (Sections 39-41).

The recovery strategy was first published in March 2014, and subsequently amended to correct the omission of the Minister responsible for Parks Canada as a responsible minister for the Nechako River population.

The Minister of Fisheries and Oceans is the sole competent minister under SARA for the Upper Fraser River, Upper Columbia River, and Kootenay River populations. The Minister of Fisheries and Oceans and the Minister responsible for Parks Canada are the competent ministers under SARA for the Nechako River population as the distribution and critical habitat of this population overlaps with the Fort St. James National Historic Site.

Success in the recovery of these listed populations depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this strategy, and will not be achieved by DFO or any other party alone. This strategy provides advice to jurisdictions and organizations that may be involved or wish to become involved in the recovery of the species. In the spirit of the National Accord for the Protection of Species at Risk, the Minister of Fisheries and Oceans invites all responsible jurisdictions and Canadians to join DFO in supporting and implementing this strategy for the benefit of the white sturgeon and Canadian society as a whole. DFO will support implementation of this strategy to the extent possible, given available resources and its overall responsibility for species at risk conservation.

The goals, objectives and recovery approaches identified in the strategy are based on the best existing knowledge at the time the strategy was developed, and are subject to modifications resulting from new information. Studies related to white sturgeon populations are ongoing, and understanding of threats and recovery approaches is evolving. DFO will continue to be guided by new information and it is recognized that adaptations to recovery approaches and scales may be required in future. The Minister of Fisheries and Oceans will report on progress within five years.

This strategy will be complemented by one or more action plans that will provide details on specific recovery measures to be taken to support conservation of the species. The Minister of Fisheries and Oceans will take steps to ensure that, to the extent possible, Canadians interested in or affected by these measures will be consulted.

Much of this report was originally written prior to 2010, and revised in 2012 to accommodate new information. At the time of revision, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was undertaking its review of an update status report with an aim of providing a status decision in late fall 2012. In November 2012, COSEWIC reassessed white sturgeon, and divided the species into four Designatable Units (DUs). These DUs differ in structure somewhat from the six Nationally Significant Populations previously identified in the 2003 assessment; however, this recovery strategy was prepared to provide publicly available direction for recovery of the species at a national scale and in response to the 2006 SARA listing of the Upper Columbia, Nechako, Upper Fraser, and Kootenay River populations, with the understanding that adaptations to recovery approaches and scales may be required in the future.

Responsible jurisdictions

The responsible jurisdiction for the White Sturgeon under SARA is DFO. Parks Canada is also a responsible jurisdiction for the Nechako River population. White sturgeon occur in British Columbia and its respective governments also contributed to the production of this recovery strategy.

Contributors / Authors

Contributors/authors to/of this recovery strategy provided valuable technical and scientific advice towards the development of this product. Their involvement is greatly appreciated and should not be interpreted to signify the support by their employer for all the contents of this recovery strategy.

Note: The following are past or present members of the National Recovery Team for White Sturgeon (formerly the National Technical Coordinating Committee). Italics denote former team members. 

Steve McAdam (B.C. Ministry of Environment – Chair of National Recovery Team)
Courtney Druce (Fisheries and Oceans Canada – co-chair of the National Recovery Team)
Gary Birch (B.C. Hydro – former Chair of the Upper Columbia River Technical Working Group)
Mike Bradford (Fisheries and Oceans Canada)
Tola Coopper (Fisheries and Oceans Canada – former co-chair of the National Recovery Team)
James Crossman (B.C. Hydro – Canadian Chair of the Upper Columbia River Technical Working Group)
Bill Green (Canadian Columbia River Intertribal Fisheries Commission)
Todd Hatfield (Ecofish Research)
Ken Malloway (Sto:lo Tribal Council)
Troy Nelson (Fraser River Sturgeon Conservation Society)
Matt Neufeld (Ministry of Forests, Lands and Natural Resource Operations – Canadian Representative on the Kootenay Recovery Team)
Louise Porto (AMEC Earth & Environmental)
Jim Powell (Freshwater Fisheries Society of British Columbia – Canadian Chair of the Upper Columbia River Technical Working Group)
Mike Ramsay (B.C. Ministry of Forests, Lands and Natural Resource Operations – Lower and Mid Fraser Technical Working Group)
Dan Sneep (Fisheries and Oceans Canada)
Colin Spence (B.C. Ministry of Environment)
Erin Stoddard (B.C. Ministry of Forests, Lands and Natural Resource Operations – Chair of the Lower and Mid Fraser Technical Working Group)
Brian Toth (Lheidli T'enneh First Nation and the Carrier Sekani Tribal Council)
Cory Williamson (B.C. Ministry of Forests, Lands and Natural Resource Operations – Chair of the Nechako and Upper Fraser Technical Working Group)
Lee Williston (B.C. Ministry of Forests, Lands and Natural Resource Operations – Lower and Mid Fraser Technical Working Group)
Chris Wood (Fisheries and Oceans Canada)

Acknowledgements

Development of this recovery strategy was partially funded by DFO and the Living Rivers Trust Fund of British Columbia. Grateful acknowledgement is also made for the significant time and effort put in by many individuals involved in this province-wide process.

Strategic environmental assessment

A strategic environmental assessment (SEA) is conducted on all SARA recovery planning documents, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals. The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally-sound decision making.

Recovery planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that strategies may also inadvertently lead to environmental effects beyond the intended benefits. The recovery planning process based on national guidelines directly incorporates consideration of all environmental effects, with a particular focus on possible impacts on non-target species or habitats. The results of the SEA are incorporated directly in the strategy itself, but are also summarized below.

While this recovery strategy will clearly benefit the environment by promoting the recovery of white sturgeon, potential effects of the recovery strategy on other species was considered. For example, the strategy calls for protection of various habitats highly used by white sturgeon, which may require restoration. However, habitat restoration for white sturgeon may impact residing species that are suited to the existing conditions. An increase in white sturgeon populations due to conservation aquaculture may lead to additional encounters or by-catch in recreational fisheries, which in turn may require increased management attention. Further information on potential interactions with other species can be found in Section 10.1 (Potential impacts on other species). Restoration activities required for the protection of white sturgeon will be based on a risk assessment of effects on other species. Taking these approaches into account, it was concluded that the benefits of this recovery strategy far outweigh any adverse effects that may result.

Residence

SARA defines residence as: “a dwelling-place, such as a den, nest or other similar area or place, that is occupied or habitually occupied by one or more individuals during all or part of their life cycles, including breeding, rearing, staging, wintering, feeding or hibernating” [SARA S2(1)].

The existence of a Residence indicates that a species at risk has invested in a specific structure that it relies upon to carry out certain life-cycle processes. Any damage or destruction of this structure would have an impact on the fitness of individual(s) of the species. With the current understanding of residence, it is not applicable for white sturgeon at this time and “residence” has not been proposed for this species.

Residence descriptions are posted when available on the SARA Public Registry.

1. Species information

Common name 
White sturgeon

Scientific name
Acipenser transmontanus

COSEWIC assessment summary
November 2003

COSEWIC status
Endangered

COSEWIC reason for designation
A long-lived species with a 30-40 year generation time and late maturity, that has suffered over a 50% decline in the total population trend in the last three generations^{Footnote 1}. Three of six populations are in imminent threat of extirpation. Extant populations are subject to threats of habitat degradation and loss due to dams, impoundments, channelization, dyking and pollution. Illegal fishing (poaching) and incidental catches are also limiting. In addition, a developing commercial aquaculture industry may also impose additional genetic, health and ecological risks to wild populations.

Canadian occurrence
British Columbia

COSEWIC status history
Designated Special Concern in April 1990. Status re-examined and changed to Endangered in November 2003. Last assessment based on an update status report.

SARA status
Endangered – Schedule 1 (2006)

Note: In November 2012, COSEWIC reassessed white sturgeon, and divided the species into four Designatable Units (DUs). These DUs differ somewhat in genetic structure and distribution from the six Nationally Significant Populations previously identified in the 2003 assessment; however, this recovery strategy was prepared to provide publicly available direction for recovery of the species at a national scale and in response to the 2006 SARA listing of the Upper Columbia, Nechako, Upper Fraser, and Kootenay River populations, with the understanding that adaptations to recovery approaches and scales may be required in the future.

2. Description of the species

2.1 Preamble

Within Canada white sturgeon occur only in British Columbia, and have been divided into six “nationally significant populations” (NSPs), based on geography, demographics and genetics: the lower, middle and upper Fraser River, Nechako River, Columbia River, and Kootenay River. All populations were assigned an Endangered status by COSEWIC in 2003; the latter four were legally listed under SARA in 2006. This document is a SARA-compliant recovery strategy for the four SARA-listed populations, but it also provides recovery and management recommendations for the lower and middle Fraser River populations (i.e., non-SARA-listed). Sections 2 and 3 (Description of the species, and Description of needs of the species) and Section 10 (Implementation) of this document discuss all populations, whereas recovery and management recommendations for SARA-listed and non-SARA-listed populations are discussed separately in other sections.

2.2 General biology

White sturgeon, Acipenser transmontanus, is the largest, longest-lived freshwater fish species in North America (Scott and Crossman 1973). Fish of over 6 m in length and over 100 years of age have been reported in the Fraser River (Scott and Crossman 1973). The species’ most distinguishing features include a mainly cartilaginous skeleton, long scaleless body covered with rows of large bony plates (called scutes) on the back and sides, shark-like (heterocercal) tail, and four barbels between the mouth and an elongated snout (Figure 1). It has a protrusible mouth with which it creates suction to capture and pick up food. Body colouration ranges from black to olive or light grey on the dorsal surface and upper edge of scutes, but is consistently white on the ventral surface (Scott and Crossman 1973).

White sturgeon are slow-growing with a delayed onset of sexual maturity. Growth rates and maturity vary significantly throughout the white sturgeon’s range. Growth rates tend to be highest where waters are warmer, growing seasons are longer, and food is abundant.

Males tend to mature at a younger age and smaller size than females.  Females and males may spawn for the first time at 26 and 11 years respectively, but often it is later (Semakula and Larkin 1968). White sturgeon may also spawn multiple times throughout their life. For example, limited data for white sturgeon in the lower Fraser River suggest that spawning intervals for females may vary from 4 to 11 years, with the interval increasing with age (Semakula and Larkin 1968, Scott and Crossman 1973). Hatchery programs for white sturgeon in the Nechako and Kootenay rivers have identified spawning intervals as short as 3 to 4 years (Steve McAdam, B.C. Ministry of Environment, personal communication). Estimated survival is very low during the first year (estimated at 0.000396% in Gross et al. 2002) and is higher for hatchery-released juveniles over 1.5 years of age (e.g., 29% in Golder Associates Ltd. 2007, Beamesderfer and Justice 2008). Survival can also be very low in some year classes due to density dependant juvenile survival (Justice et al. 2009). Survival rates are substantially higher in the juvenile and adult life stages, with estimates ranging between 91% and 97% (Gross et al. 2002, Walters et al. 2005, Irvine et al. 2007). The combined effect of low early survival and the compounding effects of subsequent mortality over many years means that relatively few individuals actually reach the old ages often cited for this species.

2.3 Life stages

For consistency, the following major life stages will be used throughout this document. This terminology has been reviewed by the NRT, but a variety of other terms may be used in the literature. The divisions into the following life stages are useful for facilitating discussion of the life stage-specific biotic processes, habitats, including the biological function, features and attributes of critical habitat, and population and distribution objectives discussed in this document.

Spawning — The spawning life stage refers to the primary period of active reproduction for mature individuals. Typically this is shortly after the peak of the spring freshet, but the actual timing varies considerably among locations. Where logical to do so, the spawning period may include staging near spawning areas immediately prior to spawning events.

Incubation — The incubation life stage refers to the period from fertilization to hatch. Hatch occurs 5 to 10 days after fertilization depending on water temperature, with temperatures in excess of 20 °C leading to abnormal development and reduced survival (Wang et al. 1985; 1987). Since incubation habitats are the same or contiguous with spawning habitats, the discussion of spawning and incubation is usually combined in this document.

Yolk sac larvae (0 – 12 days post-hatch) — During the yolk sac larvae period individuals tend to remain hidden (typically in interstitial spaces within river bed substrates) until the yolk sac is exhausted, but at the beginning of this period drift may occur until yolk sac larvae find appropriate hiding locations. The life stage ends at the onset of exogenous feeding. First feeding varies from 8–16 days post-hatch, depending on water temperature (Doroshov et al. 1983; Buddington and Christofferson 1985; Gawlicka et al. 1995). The period to 12 days post-hatch is used to capture the typical developmental range. 

Feeding Larvae (12 – 40 days post-hatch) — At the onset of the larval period individuals emerge from hiding habitats, show nocturnal drift, and initiate exogenous feeding. First feeding varies from 8–16 days post-hatch, depending on water temperature (Doroshov et al. 1983; Buddington and Christofferson 1985; Gawlicka et al. 1995). A larva’s first feeding occurs after about 200 accumulated temperature units (Boucher 2012). Nocturnal drift likely decreases predation and drift is presumed to allow feeding larvae to move to low velocity feeding habitats (e.g. side channels or floodplain). The division between the feeding larvae and early juvenile life stage is termed metamorphosis and occurs when fish take on the features of the adult form. Various ages have been suggested for metamorphosis and an age of 40 days is used here as an appropriate timeframe (Buddington and Christofferson, 1985; Deng et al. 2002).

Early Juvenile (40 days to 2 years) — While early juvenile white sturgeon are morphologically very similar to later life stages after metamorphosis, habitat use and diets may be substantially different than later life stages, primarily due to differences in body size. The 40 days to 2 years stage is one in which young fish become less susceptible to predation and by one year old fish are often observed holding in habitats that are similar to adult habitat types. The division between this life stage and the next has been set somewhat arbitrarily at two years of age. In general, once white sturgeon are one year old they tend to occupy habitat that is similar to that preferred by adults.

Late Juvenile and Adult (greater than 2 years) — Individuals greater than two years old differ in size and sexual maturity from late juveniles, but habitat for these stages is similar, so these fish can be grouped together during the rearing and overwintering phases. Food resources likely shift during this stage with an increasing trend toward piscivory in older fish. This life stage may include activities such as staging, overwintering, migration and rearing.

White sturgeon release large numbers of eggs and sperm over bottom substrates in the water column of turbulent river habitats. Spawning occurs in the late spring and early summer, typically following the highest water levels of freshet. During this time, water temperatures rise, with fast water velocities over coarse substrates (Parsley et al. 1993, RL&L Environmental Services Ltd. 1994a, Parsley and Kappenman 2000, Paragamian et al. 2002, Parsley et al. 2002, Perrin et al. 2003, Sykes et al. 2007) , though there are deviations from this general pattern. Most studies indicate that hydraulic conditions are important during spawning (Paragamian et al. 2009, McDonald et al. 2010, Sykes 2010), though substrate condition appears to have a critical effect on egg and very early life stage survival (Paragamian et al. 2009, McAdam 2011, Boucher 2012, McAdam 2012) . In the Fraser River, the only unregulated river examined, spawning has been documented primarily in large side channel habitats from mid-June through July (RL&L Environmental Services Ltd. 2000a, Perrin et al. 2003, Paradis et al. 2011). In the mainstem Columbia and Snake rivers, spawning has occurred largely in the tailwater areas of large dams (e.g., Parsley et al. 1993, Parsley and Kappenman 2000, Lepla et al. 2001, Terraquatic Resource Management 2011) or at the confluences of large tributaries possibly indicating that sturgeon select higher velocity spawning areas. In the Kootenay River, white sturgeon spawn in the mainstem far downstream of Libby Dam (Idaho, USA) whereas in the Nechako River, fish also spawn far downstream of the Kenney Dam (in and upstream of a braided section of the river) near Vanderhoof, B.C.

The number of eggs that white sturgeon females can produce (i.e., fecundity) is directly proportional to body size and has been reported by Scott and Crossman (1973) to range from 0.7 to 4.0 million eggs. For example, a 239 cm female contained approximately 0.7 million eggs (Scott and Crossman 1973). Eggs are approximately 3.5 mm in diameter, adhesive, and demersal (Deng et al. 2002).

During incubation (the life stage that begins at fertilization and ends at hatch), white sturgeon embryos gain nutrition endogenously. Hatch timing depends on water temperature and has been observed after approximately 5 to 10 days at water temperatures ranging from 11° to 21.5 °C (Wang et al. 1985). Abnormal development and reduced survival have been observed when early life stages are reared at temperatures in excess of 18 °C (Wang et al. 1985; 1987). For several days after hatch, yolk sac larvae continue to receive all nutrition endogenously from a yolk sac (van der Leeuw et al. 2006). After the yolk sac is exhausted, exogenous feeding begins and the larvae are referred to as feeding larvae. Metamorphosis is complete, including the development of adult osteological features, approximately 40 to 60 days after hatching, depending on ambient water temperature; the young fish are identical in most ways to the adult form (Wang et al. 1985, Kynard et al. 2007).

Under culture conditions the highest daily mortality rate of young sturgeon is associated with the onset of exogenous feeding (Gisbert and Williot 2002). First feeding in white sturgeon varies from 8 to 16 days post-hatch, depending on water temperature (Doroshov et al. 1983, Buddington and Christofferson 1985, Gawlicka et al. 1995). During early development under cultured conditions, a mixture of food organisms produces faster growth than diets of single species (Gisbert and Williot 2002). Studies of larval feeding under natural conditions are limited (e.g., Muir et al. 2000), but feeding observations in the wild suggest that larvae eat a variety of foods and are likely more limited by the gape size of their mouth than by food type (Steve McAdam, B.C Ministry of Environment, personal communication).

Movement and dispersal during early development are poorly understood, especially considering the importance of this life stage to recruitment. After hatching, yolk sac larvae tend to hide in interstitial spaces while endogenous yolk reserves are used (McAdam 2011, McAdam 2012). Drifting may occur during this phase until larvae reach suitable hiding locations (Howell and McLellan 2006, McAdam 2011, McAdam 2012). Emergence from hiding occurs at the initiation of exogenous feeding and leads to nocturnal drift, which is believed to allow larvae to move to preferred feeding locations (McAdam 2012). Larval drift can result in very long range dispersal: larvae were collected more than 180 km downstream of the spawning area at Bonneville Dam on the Columbia River (McCabe and Tracy 1994). This pattern of hiding and drift is consistent with a variety of field and laboratory studies for white sturgeon and other sturgeon species (Kempinger 1988, Parsley et al. 2002, Kynard et al. 2007, McAdam 2011, McAdam 2012); however, the importance of these phases to recruitment emphasizes the need to clearly identify factors affecting stage-specific survival rates.

Adult and juvenile white sturgeon are adapted to feeding in low light, benthic habitats, where prey are often located through direct contact, facilitated by highly sensitive taste receptors on barbels near the mouth (Brannon et al. 1985). Juvenile white sturgeon are primarily benthic feeders and prey include a variety of aquatic insects, isopods, mysids, clams, snails, small fish, and fish eggs (Scott and Crossman 1973, McCabe et al. 1993), but diets also vary throughout the year and among locations. In the upper Columbia River, Mysis relicta, a non-native pelagic crustacean, is the most common prey item for hatchery-released juveniles that are between one and two years of age, followed by Trichopteran larvae (Golder Associates Ltd. 2006a). Adult white sturgeon feed predominantly on fish, particularly migratory salmonids where available, although crayfish and chironomids are also consumed (Scott and Crossman 1973). In the lower Fraser population, white sturgeon have access to a broader range of food sources than in other areas of B.C., including marine and estuarine fish and invertebrates, anadromous fish, as well as seasonally abundant eulachon (Thaleichthys pacificus) and Pacific salmon runs.

Adult and late juvenile movement and migration is linked to feeding, overwintering, and spawning activities. Movement patterns appear primarily related to food type and availability, and habitat type and availability; the presence of dams and river regulation may alter natural movement patterns. For example, in the unimpounded Fraser River most individuals seem to remain on feeding grounds and exhibit relatively localized movements during the summer (RL&L Environmental Services Ltd. 2000a). Migration behaviour is observed during the fall or winter (if overwintering habitat is not immediately available), followed by a period of relatively low activity during the winter, with the timing and length of inactivity variable among populations (RL&L Environmental Services Ltd. 2000b, Nelson et al. 2004). Spring spawning migrations are more extensive compared to feeding and overwintering movements (RL&L Environmental Services Ltd. 2000a). Telemetry studies in the Columbia River indicate that while white sturgeon remain in preferred high use areas throughout the year, some individuals also move between these areas for spawning and/or feeding (e.g., Golder Associates Ltd. 2006b). Long distance migrations (greater than 1,000 km) have been observed in a few individuals that have access to the ocean (e.g., Welch et al. 2006). In the lower Fraser River, extensive migratory movements have been recorded (greater than 100 km); these movements are likely a consequence of the greater variety of prey available and their timing in-river, estuary and marine waters.

2.4 Distribution

Populations of self-sustaining white sturgeon occur in three major drainages on the Pacific coast of North America: the Fraser, Columbia and Sacramento river systems. They are found in the mainstem of these rivers, as well as several of the larger tributaries. White sturgeon can exhibit facultative anadromy and have been observed in several coastal inlets and estuaries, typically near creek and river mouths. Some migration occurs via the ocean between the three major drainages and to other coastal watersheds (Pacific States Marine Fisheries Commission 1992). While these movements are apparently rare, the extent of marine migration and exchange is poorly understood.  Studies are currently being undertaken to better understand estuary and marine use in the lower Fraser population.

Six white sturgeon NSPs exist in Canada (all in B.C.) and are referred to as the Lower Fraser River, Middle Fraser River, Upper Fraser River, Nechako River, Upper Columbia River, and Kootenay River populations (Figure 2 and Figure 3) (Smith et al. 2002, COSEWIC 2003). In this document populations are often discussed separately to accommodate differences in biology, threats, and recovery measures. Populations are discussed in geographic order from west to east--no significance is implied by this order.

2.4.1 Fraser River

The lower, middle and upper Fraser River populations are the only ones not directly fragmented by dams, as no dams are present on the Fraser River mainstem.  Within the Fraser River, white sturgeon have been observed in the mainstem from the marine estuary upstream past the Morkill River, northwest of McBride, a distance of approximately 1,100 km (Yarmish and Toth 2002). They are also found in a number of large tributaries including the Nechako and Stuart systems (a total of 400 km in length), the Harrison and Pitt rivers, and the confluences or lower reaches of numerous large and small tributaries, such as the Bowron, McGregor and Torpy rivers (Ptolemy and Vennesland 2003). Present distribution in the Fraser River is believed to be the same or similar to historic distribution with the exception of Seton, Thompson, and Nechako rivers, where white sturgeon may now be more restricted than they were historically due to dams. White sturgeon have also been confirmed in several large lakes including Seton, Pitt and Harrison lakes, and reported in several others, including Williams and Kamloops lakes.

Movement within the Fraser River mainstem is generally unrestricted, with the possible exception of seasonal rapids within the Fraser Canyon, such as at Hells Gate. This confined canyon section, which is about 210 km from the mouth is an upstream movement barrier to many fish species. Salmon, trout, char, and white sturgeon have nevertheless been recorded moving upstream and downstream. There have been two documented downstream movements and one upstream movement of white sturgeon through Hells Gate (Fraser River Sturgeon Conservation Society 2012).

Although movements between the lower, middle, and upper Fraser River and Nechako River populations are possible and have occasionally been documented (Lheidli T’enneh Band 2001, Golder Associates Ltd. 2003a, Fraser River Sturgeon Conservation Society 2012), genetic differentiation in mitochondrial DNA suggests that Fraser River white sturgeon exist as reproductively isolated populations in these sections of the watershed (Smith et al. 2002). Tagging and genetic data also strongly suggest that the Nechako River population does not interbreed or mix significantly with the upper Fraser mainstem population (Smith et al. 2002). Drauch Schreier et al. (2012), using microsatellites, found evidence supporting genetic differentiation between Fraser white sturgeon populations above and below Hell’s Gate, and evidence of population substructure in the Fraser River above Hell’s Gate and the Nechako River.  Additional research on population substructure and spawning groups in the Fraser River above Hell’s Gate may help guide conservation efforts for these populations (Drauch Schreier et al. 2012).

The lower Fraser River population is thought to be relatively productive, as they have access to marine derived nutrients (e.g. salmon) and estuarine habitats not available to other Canadian populations. Juveniles and adults of the lower Fraser River population disperse widely, especially when food sources are abundant, such as during smelt and eulachon spawning, and during sockeye, Chinook pink and chum salmon migration and spawning.  During these periods sturgeon move extensively between holding, prey spawning and carcass depositional areas.

2.4.2 Nechako River

In the Nechako system, white sturgeon can be found from the confluence with the Fraser River, upstream to Cheslatta Falls, and throughout most of the Stuart River, which is a major tributary, and several large lakes such as Fraser, Takla, Stuart and Trembleur lakes.  Some Nechako River white sturgeon have been observed to move into the Fraser River confluence for feeding and overwintering, but these movements are limited (Lheidli T’enneh First Nation 2008, Sykes 2008). Seasonal migrations to the Stuart and Fraser Lake systems coincide with the migrations of salmon, suggesting that both lake systems are important feeding and rearing areas for this population (Liebe et al. 2004). The Kenney Dam has altered the natural flow regime and instream habitats, which may have affected movement patterns of white sturgeon (Nechako White Sturgeon Recovery Initiative 2004).

2.4.3 Columbia River

White sturgeon historically had access from the ocean to Columbia Lake in the upper Columbia River and to Shoshone Falls in the upper Snake River. Populations in the upper reaches of the basin were most likely resident and benefited from the seasonal availability of anadromous salmon.  White sturgeon inhabited the upper Columbia mainstem, lower Spokane River, lower Pend d’Oreille River, and lower Kootenay River to Bonnington Falls, and likely also used portions of smaller tributaries including the Sanpoil, Kettle, Slocan, and Salmo rivers (Hildebrand and Birch 1996, Prince 2001). Distribution was probably patchy with fish likely utilizing these distinct habitats seasonally for specific life processes. White sturgeon were reported during the early 1900s in the Columbia River mainstem downstream from Castlegar, the lower Kootenay River downstream of Bonnington Falls, Arrow Lakes, Big Eddy near Revelstoke, and at the present site of Mica Dam (Prince 2001).

The current distribution of white sturgeon in the upper Columbia River extends from Revelstoke Dam (REV) to Grand Coulee Dam in Washington, and the lower Kootenay River from its confluence with the Columbia River to Brilliant Dam (Figure 3). Studies on this population focus on three geographic areas:

1. Arrow Lakes Reservoir (ALR), upstream of Hugh L. Keenleyside Dam (HLK)
2. the transboundary reach, which extends downstream from HLK to Roosevelt Reservoir (FDR) (Upper Columbia White Sturgeon Recovery Initiative 2012); and
3. Roosevelt Reach (i.e., FDR). This recovery strategy addresses only white sturgeon and habitats upstream of the Canada-U.S. border

The ALR component of the Columbia River white sturgeon population has access to approximately 230 km of riverine and lacustrine habitat from REV downstream to HLK. Abundance of the ALR component is substantially lower than that of the other two population components. Radio-tagged sturgeon have been observed to overwinter at Beaton Flats and several move during spring and summer upstream to Revelstoke or into Beaton Arm near the confluence with the Incomappleux River (see Section 8: Critical habitat). Most assessment effort has concentrated on the upper ALR and a total of 32 unique fish have been captured there (Golder Associates Ltd. 2006c). More recently, considerable effort was expended on assessments in the narrows section of ALR (see Section 8: Critical habitat), which resulted in an additional 10 unique captures (Prince 2002, 2003, 2004).

White sturgeon in the transboundary population have access to habitats from HLK to Grand Coulee Dam (Figure 3). Habitat in Canada for this population includes approximately 56 km of riverine habitat located between HLK and the Canada-U.S. border, and the small section of river in the lower Kootenay River below Brilliant Dam. Studies have been conducted on the transboundary population component since 1990 (Upper Columbia White Sturgeon Recovery Initiative 2012). Movements of white sturgeon between Canada and the U.S. have been observed (Golder Associates Ltd. 2006b), but white sturgeon within the transboundary reach tend to remain within fairly localized areas and some fish may make larger movements related to spawning activity (Golder Associates Ltd. 2006b, Nelson and McAdam 2012). Habitats within this reach include large, deep, eddy areas that are preferred areas for both white sturgeon and their prey items (Golder Associates Ltd. 2006b). Concentrations of overwintering adult white sturgeon have been observed mostly between HLK eddy and Norns Creek (7 km downstream of HLK), as well as Fort Shepherd eddy, Waneta eddy, and, to a lesser extent, in the lower portion of the Kootenay River below Brilliant Dam (i.e., Kootenay eddy, near Brilliant Bridge, Brilliant Dam plunge pool; see Section 8: Critical habitat).

Research since 2005 has substantially increased our knowledge of sturgeon distribution and density in the approximately 40 km section of river between the Canada-U.S. border and FDR (Howell and McLellan 2007a, b, Howell and McLellan 2009, 2011). Most adult sturgeon occur in the river-reservoir transition zone and upstream to the border, with much lower densities in the FDR main pool (Howell and McLellan 2007a, b). Spawning has been identified at two locations near Northport and China Bend (Washington). Although these fish are also undergoing recruitment failure, occasional low levels of recruitment are detected (e.g., 1997). Although residency is high for individuals at specific locations (Nelson and McAdam 2013), both demographic patterns (McAdam 2012) and movements during the spawning season (Howell and McLellan 2007a, b) suggest movement between the areas occurs, particularly with the Waneta spawning site.

Remnant population components may also exist upstream of the ALR component (i.e., between REV and Mica Dam, and in Kinbasket Reservoir) but investigations have not captured white sturgeon despite considerable effort (RL&L Environmental Services Ltd. 1996a, 2000b, Prince 2009). Given the large size of these reservoirs, the failure to catch white sturgeon does not prove their absence, but suggests that population abundance is at most very low (RL&L Environmental Services Ltd. 2000b).

There are several hypotheses regarding the historic distribution and population structure of upper Columbia River white sturgeon. For example, recent research suggests that white sturgeon in the Canadian portion of the Columbia River historically consisted of three or more reproductively isolated populations (Nelson and McAdam 2012). However Drauch Schreier et al. (2013), using a nuclear DNA analysis that represented current levels of genetic diversity, found that white sturgeon in the transboundary reach were not genetically different from downstream populations. Investigations of historic genetic population structure are ongoing. However, for the purpose of recovery planning white sturgeon in the Columbia River from REV to the Canada-U.S. border are considered to be a single population or designatable unit. This recovery strategy does not consider the FDR population component that resides in the U.S. and it does not consider remnant, demographically isolated population components (e.g., Revelstoke, Kinbasket, Slocan systems, and portions of the lower Kootenay River between Corra Linn and Brilliant Dams)^{Footnote 2}.

2.4.4 Kootenay River

The Kootenay^{Footnote 3} River population of white sturgeon extends from Kootenai Falls, Montana, located 50 river-kilometres below Libby Dam (Idaho), downstream through Kootenay Lake to Corra Linn Dam on the lower West Arm of Kootenay Lake, British Columbia. 

Kootenai Falls likely represented an impassable natural barrier to upstream migration of white sturgeon, although there are a handful of anecdotal accounts describing the presence of white sturgeon upstream of Kootenai Falls in Montana and British Columbia (Jason Flory, U.S. Fish and Wildlife Service, personal communication). During the mid-1970s, after construction of Libby Dam, Montana Fish, Wildlife & Parks introduced five adult white sturgeon into Koocanusa Reservoir. One of these was captured at Wardner Bridge in 1980, but the fate of the other sturgeon is unknown, and some or all of these fish may have been captured by anglers.

A natural barrier at Bonnington Falls downstream of Kootenay Lake has isolated the Kootenay River white sturgeon from other white sturgeon populations in the Columbia River basin since the end of the Pleistocene, approximately 10,000 years ago (Northcote 1973). Spawning habitat is located in the U.S., whereas much of the adult and juvenile rearing habitat is located in Kootenay Lake and the Canadian portion of Kootenay River.  White sturgeon occur in very small numbers in Duncan Reservoir and Slocan Lake (RL&L Environmental Services Ltd. 1998a, b).

The Slocan River is a tributary of the Kootenay River and several white sturgeon have been captured in Slocan Lake (RL&L Environmental Services Ltd. 1996b). Two white sturgeon captured in Slocan Lake were aged using fin ray samples and assessed to be younger than Brilliant Dam (RL&L Environmental Services Ltd. 1996b). It is thought that these fish may have en entrained from upstream on the Kootenay River and subsequently moved into Slocan Lake (RL&L Environmental Services Ltd. 1996b, 1997).

Tracking studies in Kootenay Lake located sturgeon released upstream of the Canada-US border (Neufeld and Spence 2004a, Neufeld and Rust 2009). A 2005 study tracked the dispersal of tagged juvenile white sturgeon from release sites in the US (n=4) and Canada (n=1) upstream of Kootenay Lake (Neufeld and Rust 2009). All fish released in the shallow, higher gradient reach above Bonners Ferry, Idaho moved downstream to the lower gradient reach below Bonners Ferry within 2 months of release (Neufeld and Rust 2009). Meanwhile, juveniles released within this lower gradient section showed movement both upstream and downstream, with 9% (n=3) of tagged fish moving from river release sites to Kootenay Lake (Neufeld and Rust 2009). High gradient locations are characterized by typical gradients of 0.6 m/km^-1 and velocities greater than 0.8 m/sec^-1, whereas low gradient reaches were characterized by typical gradients of 0.02 m/km^-1 and velocities less than 0.4 m/sec^-1 (Neufeld and Rust 2009). 

2.5 Population abundance and trends

Long-term trend data are generally lacking for all white sturgeon populations because most studies are relatively recent (though see Walters et al. 2005, Whitlock and McAllister 2012). Various lines of evidence can be used to demonstrate that population abundance has declined in many parts of the Canadian range, particularly in the Nechako, Columbia and Kootenay rivers, where the timing of the decline is associated with the installation of dams and subsequent river regulation. In the lower Fraser River, the decline is primarily related to historic harvest and habitat loss.  In the middle and upper Fraser River, abundance is likely food and habitat limited and white sturgeon are thought to be at or near historic levels. Recruitment failure^{Footnote 4} is ongoing in the Nechako, Columbia and Kootenay, which has resulted in highly skewed age structures, but regular recruitment continues to occur in the upper, mid and lower Fraser and age structure appears normal (Ptolemy and Vennesland 2003).

The total estimated population abundance for Fraser, Nechako, Columbia and Kootenay white sturgeon populations are presented in Table 1. The estimates are for wild fish (i.e., not hatchery produced fish) greater than 40 cm total length. Three population estimates are provided for the Columbia River population, corresponding to census studies that divide this population into the transboundary, ALR, and FDR population components. The estimated abundance for the Kootenay River population includes fish captured in both Canada and the U.S., since these components cannot be separated.

Updated abundance estimates of mature white sturgeon are provided in Table 2 for the year 2012. The estimates provide information on the reproductive potential of each population and are based on estimates of fish greater than 160 cm total length and the latest estimates of survival. 

a. The 2011 estimate is for fish > 40 cm and < 279 cm. The estimate does not include individuals larger and smaller due  to the small number of tagged individuals and low capture rates in these size groups (Nelson et al. 2013). This population estimate, generated through a mark-recapture study, is the estimate that is used for lower Fraser population management and recovery planning as it is current and likely reflects population trends.  Additional population estimates have been completed using mark-recapture and other data by Walters et al. (2005) and Whitlock and McAllister (2012).  These modeling exercises and their associated estimates and management recommendations are also considered in the management of the lower Fraser population and development of recovery actions.

b. Values for the lower Fraser describe the 95% highest density rather than a parametric confidence interval (see Nelson et al. 2004).

c. Mean ± standard deviation.

d. Estimates are for fish > 50 cm fork length.

e. These 3 segments of the Columbia River population are tabulated separately and correspond to separate census studies for each population component.

f. These values are for the year 2003.

g. These values are for the year 2003 and combine separate estimates for two river sections from HLK to the U.S. border (see text for further information).

h. This estimate is based on analysis of catch, marking, and recapture data from 1978-2012 for naturally-produced Kootenai sturgeon in the population in 2013 (Beamesderfer et al. 2014). This estimate is for wild (i.e., naturally produced) white sturgeon -- there are many juvenile hatchery releases that are now >40 cm.  This population estimate is also based on a combined Canadian and U.S. estimate since components cannot be separated.

i. The total uses the estimate for the most recent year in the lower Fraser River.

a. Population estimated in 1999 and assumes 95% of uncorrected estimate are mature with 94% survival rate per year projected to 2012. There are no adult survival estimates specific to the Nechako River population; this assumed survival value is taken from Whitlock (2007)  and Irvine et al. (2007).

b. These 3 segments of the Columbia River population are tabulated separately and correspond to census studies that divide the population. Further information on these population components are provided in Section 2.4 (Distribution). 

c. Population estimated in 2003 and is projected to 2012 based on a 97% survival rate (Irvine et al. 2007) per year. 

d. The uncorrected abundance estimate is for the year 2003. The 2012 estimate assumes 90% are mature with a mean annual survival rate of 97% (Irvine et al. 2007) per year projected to 2012. Abundance estimates are for wild (i.e., naturally produced) fish.

e. Population estimated in 2006 and assumes 70% of the uncorrected abundance estimate are mature (Howell and McLellan 2007b) with 97% survival rate (Irvine et al. 2007) per year projected to 2012.

f. This is a revised draft estimate based on analysis of 1977-2008 data for naturally-produced Kootenai sturgeon in the population in 2007 (Beamesderfer et al. 2009). Current analyses estimates  a 96% survival rate per year (Beamesderfer et al. 2009; Matt Neufeld, B.C. Ministry of Forests, Lands and Natural Resource Operations, personal communication) projected to 2012. This population estimate is based on a combined Canadian and U.S. estimate since components cannot be separated out. 

2.5.1 Fraser River

Based on a size criterion of 160 cm minimum fork length^{Footnote 5}, a total of at least 9,394 adults were estimated to be present throughout the Fraser River: 8,460, 749 and 185 adults in the lower, middle and upper Fraser River, respectively (Ptolemy and Vennesland 2003, Nelson et al. 2008; Table 2). The estimates indicate that approximately 90% of white sturgeon in the Fraser River occur downstream of Hell’s Gate.

No trend data are available for white sturgeon populations in the upper and mid–Fraser River, but abundance is believed to be naturally low in this region and within the historic range (Ptolemy and Vennesland 2003, Lheidli T’enneh First Nation 2009). This conclusion is based on repeated sampling, evidence for consistent recruitment (age structure is typical of a self-sustaining population), and the general absence, both now and historically, of direct threats to sturgeon or their habitats. However, abundance of prey such as anadromous salmon is significantly less than historic levels.

White sturgeon abundance in the lower Fraser River was significantly reduced by unsustainable harvesting through the commercial fishery for sturgeon in the late 1800s and early 1900s (Echols 1995, Walters et al. 2005). Low abundance continued after this time due to unregulated by-catch retention in the First Nations, and commercial salmon net fisheries (Waters et al. 2005). Catch management was also limited in the recreational kill fishery until the early 1990s (Walters et al. 2005). Habitat loss and prey reductions have been implicated in keeping abundance below historic levels; the lower Fraser has had significant losses of estuary, floodplain and side channel habitats (Rosenau and Angelo 2005), and salmon, smelt and eulachon spawning returns are lower than historic levels (Fisheries and Oceans Canada 2010a). Abundance monitoring in the lower Fraser River has been underway since 1985, and has been more intensive since 1995, utilizing techniques such as radio telemetry, statistical analysis of commercial and recreational catches, mark-recapture, and life history studies (Lane 1991, Swiatkiewicz 1992, RL&L Environmental Services Ltd. 2000a, Nelson et al. 2004, Nelson et al. 2006, 2007, Nelson et al. 2008, 2009, Nelson et al. 2010, Nelson et al. 2011, Nelson et al. 2012). Recent population estimates by Whitlock and McAllister (2012) are somewhat higher than prior estimates (Walters et al. 2005, Nelson et al. 2011); however, this difference was attributed to the more explicit incorporation of fish movement by Whitlock and McAllister (2012). Recent reports (Nelson et al. 2012) draw attention to declines in total population since 2003, but the current population is within 10% of the 2001 estimate and has overlapping confidence limits, and abundance of mature individuals has increased markedly since 2004. Additionally, lower abundance of smaller size classes may reflect a recruitment pulse that apparently occurred in 1996-1997 (Whitlock 2007). Considering the longevity of the species and the potential for long term recruitment patterns, current research indicates a relatively normal age structure and variable recruitment (Nelson et al. 2009, Nelson et al. 2012).

2.5.2 Nechako River

Population monitoring on the Nechako River began in 1982 and became more intensive in 1995 (Dixon 1986, RL&L Environmental Services Ltd. 2000a) using radio telemetry, recreational catch statistics, mark-recapture estimates and life history studies.  Age distribution is highly skewed to older individuals and indicates little or no recruitment to the population since 1967 (McAdam et al. 2005).  Population models developed by Korman and Walters (2001) estimated that approximately 150 mature females remain in the Nechako River and that this number would decline to 25 by 2025.  Immediate recovery of juvenile recruitment would not improve spawner abundance for at least 25 years due to late maturation of this species.  Total abundance was estimated to be 571 in 1999 (Table 1).  Assuming a mortality rate of 0.06, the expected population in 2012 is 243 (Table 2).  Collecting additional census data has been a lower priority than efforts to address recruitment failure (Cory Williamson, B.C. Ministry of Forests, Lands and Natural Resource Operations, personal communication).

A hatchery program focusing on conservation objectives operated as a pilot program for three years, and released a total of 15,000 juveniles between 2006 and 2008 (Cory Williamson, B.C. Ministry of Forest, Lands, and Natural Resource Operations, personal communication). In 2013, the Freshwater Fisheries Society of British Columbia and the British Columbia provincial government announced development of the Nechako White Sturgeon Conservation Centre, which will serve as a hatchery and research centre in Vanderhoof. The Centre is expected to become operational in the spring of 2014. The aquaculture program will be used to produce the founder population and eggs/larvae for habitat restoration research.

2.5.3 Columbia River

In the Columbia River, population monitoring has been underway since 1990 (Hildebrand et al. 1999, Upper Columbia White Sturgeon Recovery Initiative 2002).  Separate estimates are provided for components of the population above and below HLK based on census studies (Table 1).  From HLK to the Canada-U.S. border (transboundary reach) the combined population was estimated to be 1,157 (95% CI: 414 - 1900; Irvine et al. 2007), with an additional 2037 (95% CI 1093 – 3223) fish estimated downstream of the Canada-U.S. border in FDR (Howell and McLellan 2007a). The population estimate for the transboundary reach was further divided into two strata: A) HLK to 20 km downstream; and, B) from km 20 to the U.S. border (Irvine et al. 2007).  For Strata A, the 2004 population was estimated to be 590 (95% CI 254-925), whereas Strata B was estimated at 566 (95% CI 158-974) (Robyn Irvine, Poisson Consulting Ltd., personal communication).

For the ALR population component, the number of mature wild white sturgeon in 2012 is estimated at approximately 40 fish (Table 2).  Anecdotal evidence indicates that white sturgeon have been observed upstream of REV, but efforts to confirm this empirically have been unsuccessful (Prince 2009). Recent data indicate that abundance of wild white sturgeon in the Columbia River will decline by an additional 50% over the next 25 years (Golder Associates Ltd. 2005a).

The Columbia River population is considered at significant risk of extinction in the wild given strong evidence that, for several decades, natural recruitment has been too low to sustain itself.  Yearly spawning has been documented for the transboundary population component, since 1993 (Golder Associates Ltd. 2004, Upper Columbia White Sturgeon Recovery Initiative 2012).  Spawning has also been documented for the ALR population component, but it has been intermittent (Golder Associates Ltd. 2006c). Analyses of age structure data are still being developed, but preliminary information suggests that recruitment began to decline in 1969, and has been very low since 1985 (RL&L Environmental Services Ltd. 1994a; Steve McAdam, personal communication, Hildebrand et al. 1999). 

Spawning has been confirmed at four locations: i) the Pend d’Oreille River at its confluence with the Columbia River, which is referred to as the Waneta spawning site; ii) a small riverine section below REV along the bank of the golf course; iii) immediately downstream of the Arrow Lakes Generating Station at HLK (Terraquatic Resource Management 2011) and, iv) two sites below the U.S. border at Northport, Washington Section 8: Critical Habitat).  An additional spawning site has been identified based on the capture of larvae at Kinnaird (near the Kootenay-Columbia River confluence), but further study is required to confirm the precise spawning location (Golder Associates Ltd. 2008).  It is unclear whether current spawning sites in the Columbia were used prior to construction of the dams, and the extent to which the dams artificially separated individuals from the same population.  Preliminary evidence indicates that white sturgeon within the ALR and some fish downstream of HLK are genetically similar (Nelson and McAdam 2012), and evaluation of fin ray chemistry indicates that most fish residing immediately downstream of Keenleyside Dam may have reared upstream of that location (Clarke et al. 2011).

In 2001, a hatchery program was initiated as a conservation measure; hatchery releases started in 2002, with fish that were hatched in 2001. As of January 1, 2012, approximately 164,585 hatchery juveniles have been released into the Upper Columbia recovery area: 38,368 into the Roosevelt Reach, 93,524 into the Keenleyside Reach, and 36,693 into ALR Reach (James Crossman, B.C. Hydro, personal communication).  In addition, 1,454,010 larvae have been released into the ALR Reach (James Crossman, B.C. Hydro, personal communication). 

Studies were initiated in the ALR to determine distribution and habitat use by released hatchery fish.  Early indications suggest the areas with highest sustained presence of juveniles were between Wells and Crawford creeks (Golder Associates Ltd. 2009).  Hatchery juveniles have been observed concentrated in the Robson reach between HLK and the Norns Creek fan, and in a series of smaller eddies downstream to Waneta Eddy near the Canada-US border; these areas are likely used for feeding and overwintering (Golder Associates Ltd. 2006b).  Hatchery-produced juveniles are regularly observed, along with a few wild juveniles, especially around the mouths of the Kettle and Colville rivers and at Marcus Flats (see Section 8: Critical Habitat).  Concentrations of juveniles may be influenced by the river/reservoir interface in the ALR (Golder Associates Ltd. 2009).  It is assumed that wild fish would behave similarly to hatchery fish.  Survival through the first 6 months for fish age 1 to 1.5 was estimated at 29% (approximate 95% CI = 11%-54%) for juveniles released into the Columbia River downstream of HLK in 2001 (Golder Associates Ltd. 2007 as reported by Beamesderfer and Justice 2008). There is currently no evidence of density-dependence associated with the releases into the Upper Columbia River (James Crossman, B.C. Hydro, personal communication). 

2.5.4 Kootenay River

Population surveys in the Kootenay River began in 1977 and became more intensive after 1990, with radio telemetry, recreational catch monitoring, mark-recapture estimates and life history studies being conducted (Duke et al. 1999, Paragamian et al. 2005).  Existing abundance estimates are for wild adult fish throughout the transboundary reach from Libby Dam to Bonnington Falls (Table 1 and Table 2).  Analysis of age structure indicates recruitment began to decline in the mid-1960s (Partridge 1983 cited in Duke et al. 1999, Paragamian et al. 2005), and has been negligible since 1974, the year Libby Dam became operational.  Total abundance was estimated in 2000 to be 760 individuals. Beamesderfer et al. (2009) conducted revised analyses based on 1977-2008 data and estimated approximately 1,000 naturally-produced Kootenai sturgeon in the population for 2007 (Table 1 and 2).  The same analysis indicated that approximately 3,000 fish were present in 1989 within both Canada and the U.S. At an estimated mortality rate of 4% per year the remaining wild population will fall below 50 fish in 2080 (Beamesderfer et al. 2009).

The U.S. Fish and Wildlife Service listed the Kootenai River white sturgeon population as an endangered species on September 6, 1994 under the authority of the Endangered Species Act of 1973 (U.S. Fish and Wildlife Service 1999).  Conservation aquaculture operations by the Kootenai Tribe of Idaho (KTOI) were initiated in 1990 with funding provided by the Bonneville Power Administration.  Joint biological investigations began in 1994 with the cooperation of the Idaho Department of Fish and Game, the B.C. Ministry of Environment, and KTOI (Neufeld 2006).  A total of 200,274 Kootenai white sturgeon were released from 1992 through 2011 (Kootenay Tribe of Idaho 2012). Significant releases began in 1997 after the hatchery was identified as a critical component of the Recovery Plan; hatchery releases prior to 1997 were largely experimental. Annual releases have ranged from about 3,000 to 37,000 fish per year from 2003 to 2009 (average 21,000) (Kootenay Tribe of Idaho 2012). The hatchery and release program is ongoing (Matt Neufeld, B.C. Ministry of Forests, Lands and Natural Resource Operations, personal communication).  Current production is approximately 15,000 per year from the combined U.S. and Canadian facilities.

Subsequently, 2,938 Passive Integrated Transponder (PIT)-tagged fish were recaptured as part of a long term monitoring program (Justice et al. 2009). Annual survival rates of marked groups ranged from 0.01 to 0.84 (mean = 0.45) during the first year, from 0.48 to 1.0 (mean = 0.84) in the second year, and averaged 1.0 during all subsequent years (Justice et al. 2009).  Results to date provide strong evidence of density- and size-dependent mortality in hatchery-reared juvenile white sturgeon in the Kootenai River, and have led to recommendations for management actions that prioritize the release of fewer, larger-sized fish (Justice et al. 2009).

2.6 Importance to people

White sturgeon have been important to the spiritual, aesthetic and economic history of the people of British Columbia. Sturgeon have traditional cultural values to many First Nations in B.C. and these values continue to be maintained.  The predominant values of white sturgeon to non-aboriginal communities have shifted from those of a natural resource commodity to those in which white sturgeon are appreciated as a species, and as a component of a healthy ecosystem. Consequently it is expected that the general public would have high non-market (existence and bequest) values for this iconic species. Other values for white sturgeon include recreational and guided angling, Aboriginal fishing, scientific inquiry, aquaculture, and ecosystem education. These values are discussed in greater detail for Fraser populations in the Fraser River White Sturgeon Conservation Plan (Fraser River White Sturgeon Working Group 2005). In addition, a grade school level education program implemented by the Fraser River Sturgeon Conservation Society and HSBC Bank of Canada has been ongoing throughout the province since 2005. Many stakeholders have been working to support white sturgeon recovery since before the species was designated as endangered. For example, the Upper Columbia White Sturgeon Recovery Initiative (UCWSRI) has conducted a communication and public awareness program since 2000, in conjunction with the B.C. Hydro Fish and Wildlife Compensation Program – Columbia Region. One component of this program provides primary school teaching aids, and has involved primary and high school students in annual hatchery release programs since 2003. Efforts by the Nechako Community Working Group were also underway for the Nechako River population prior to its listing.