BC Conservation Data Centre: Conservation Status Report
Acipenser transmontanus pop. 2
White Sturgeon (Upper Columbia River Population)
| Scientific Name: | Acipenser transmontanus pop. 2 |
|---|---|
| English Name: | White Sturgeon (Upper Columbia River Population) |
| Provincial Status Summary | |
| Status: | S1 |
| Date Status Assigned: | December 01, 1994 |
| Date Last Reviewed: | April 24, 2018 |
| Reasons: | Relatively small population of individuals having little or no natural recruitment to the population. |
| Range | |
| Range Extent: | E = 5,000-20,000 square km |
| Range Extent Comments: | Total of 12,190 square km (COSEWIC 2012). This DU is restricted to the mainstem Columbia River between the U.S. border and Revelstoke Dam in BC, here it encompasses about 425 km of the upper Columbia River. |
| Area of Occupancy (km2): | F = 126-500 |
| Area of Occupancy Comments: |
COSEWIC (2012) estimates the area of occupancy of to be 1760 square km. Arrow Lakes Reservoir: Linear distance of occupancy estimated at 163 km based on presence of tagged individuals in the reservoir (Golder Associates Ltd. 2005). Individuals are usually aggregated at Beaton Flats overwintering area. Transboundary group: Linear distance of occupancy estimated at 56 km, the distance from HLK to the Canada-US border (UCRWSRI 2002). Aggregations have been observed below HLK, Kootenay Eddy, Kootenay River confluence, Fort Shepherd Eddy, and Waneta Eddy (UCRWSRI 2002). |
| Occurrences & Population | |
| Number of Occurrences: | B = 6 - 20 |
| Comments: |
In the Canadian portion of the Columbia River, two groups of White Sturgeon are separated by Hugh L. Keenleyside Dam (HLK): i) Arrow Lakes Reservoir; and, ii) upper Columbia River below HLK (also known as the transboundary reach (UCRWSRI 2002). Movements across HLK are infrequent (R. L. & L. Environmental Services Ltd. 2000); observations of few sonic tagged individuals moving downstream of the Canada-US border (~70 km) (Golder Associates Ltd. 2004). There is one confirmed spawning site and four overwintering sites above HLK, and four confirmed spawning sites and six overwintering sites below HLK (COSEWIC 2012). |
| Number of Occurrences with Good Viability / Ecological Integrity: | A = None (zero) |
| Comments: | White Sturgeon in the Columbia River most likely had access and may have accessed the Pacific Ocean. However, habitat fragmentation due to the building of large hydroelectric facilities has created isolated populations (UCRWSRI 2002). There is almost complete failure of natural recruitment in this population of white sturgeon (UCRWSRI 2002). Data indicates that the population will decline to 50% within 10 years and 75% within 20 years, which will cause severe diversity bottlenecks (UCRWSRI 2002). This is more severe in the Arrow Lakes Reservoir group, since its population (estimated between 49 and 185 individuals (Golder Associates Ltd. 2005) is near the functional extinction level of 50 (UCRWSRI 2002). |
| Number of Occurrences Appropriately Protected & Managed: | A = None |
| Comments: | Recovery efforts (e.g., recovery initiative, broodstock collection, hatchery program, juvenile releases & monitoring) commenced in 2000 for the transboundary group (UCRWSRI 2002). Plans for managing the Arrow Lakes Reservoir group are currently unknown. |
| Population Size: | C = 250 - 1,000 individuals |
| Comments: |
Based on zero recruitment and a 0.04 mortality rate, these numbers have been extrapolated to 789 mature individuals below HLK, and 41 individuals above HLK, for a total of 830 reproductive individuals in 2012 (COSEWIC 2012). The transboundary population was estimated at 1400 individuals, based on mark-recapture data models (UCRWSRI 2002). More recent studies estimate the transboundary population at 1135 (95% CI of 905 to 1520) using survival rates (Golder Associates Ltd. 2003c). The Arrow Lakes Reservoir population is estimated between 49 and 189 individuals; based on mark-recapture data models (Golder Associates 2005). |
| Threats (to population, occurrences, or area affected) | |
| Degree of Threat: | B = High |
| Comments: |
The effects of dam construction and ensuing river regulation and their combined effects on spawning and rearing habitat are undoubtedly the most serious contemporary threat to White Sturgeon in the Upper Columbia.Recent modelling and experimental work by McAdam (2012) has provided strong evidence of the causal mechanisms behind recruitment failure in regulated rivers. The White Sturgeon is a fluvial species and, although it regularly occurs in large lakes, it requires flowing water to complete its life cycle (COSEWIC 2012). Both groups of white sturgeon are subject to threats of habitat degredation and loss through dams, impoundments, channelization, dyking and pollution (UCRWSRI 2002). |
| Trend (in population, range, area occupied, and/or condition of occurrences) | |
| Short-Term Trend: | E = Decline of 30-50% |
| Comments: |
COSEWIC (2012) estimates the decline to be approximately 45% over the last three generations (40 years/generation). There is almost complete failure of natural recruitment in this population of white sturgeon (UCRWSRI 2002). Both groups consist of older adults. Younger age classes have not been present since 1966 and 1980 for the Arrow Lakes Reservoir (ALR) and transboundary groups respectively (UCRWSRI 2002; Golder Associates Ltd. 2005). Data indicates that the population may decline to 50% within 10 years and 75% within 20 years, which may cause severe diversity bottlenecks (UCRWSRI 2002). This is more severe in the ALR group, since its population (estimated between 49 and 185 individuals; Golder 2005 in prep) is near the functional extinction level of 50 (UCRWSRI 2002). |
| Long-Term Trend: | AD = Decline of >50% |
| Comments: |
COSEWIC (2012) estimates that the decline of Upper Columbia white sturgeon has been greater than 50%, and at least 45% over the last three generations. This population is projected to decline more than 95% over the next three generations (COSEWIC 2012). For the transboundary group, trends from 1993 projected to 2025 (using initial population of 1135 in 1993) estimate population declines to under 400 individuals (Golder Associates Ltd. 2003c). See also Short-Term Trend. |
| Other Factors | |
| Intrinsic Vulnerability: | A=Highly vulnerable |
| Comments: | White sturgeon are highly vulnerable species due to their longevity, late sexual maturation, and long spawning interval times. In the Columbia River population, mature males were observed to be smaller (106 to 207 cm FL) and younger (16 to 46 years) than females (137 to 271 cm FL; 27 to 65 years) (UCRWSRI 2002). The UCRWSRI committee (2002) indicates that the female spawning interval in the upper Columbia River was much greater than the 3 years reported for the lower Columbia in the United States. Even though spawning is observed yearly in the transboundary group (UCRWSRI 2002), a lack of recruitment does not allow any recovery from population losses. |
| Environmental Specificity: | C=Moderate. Generalist or community with some key requirements scarce. |
| Comments: | White sturgeon are highly adapted to riverine systems and are opportunistic feeders (UCRWSRI 2002). Populations throughout the Columbia and Kootenay river systems display a broad range of environmental preferences, however, it is not known if preferred habitats have been reduced in these systems. The upper Columbia River population may have spawning cues based on water temperature and/or discharge (R. L. & L. Environmental Services Ltd. 2001), however, it is not known how changes to these cues due to river regulation has impacted spawn timing and periodicity. |
| Other Rank Considerations: | |
| Information Gaps | |
| Research Needs: | The UCRWSRI (2002) has identified several research requirements including: i) water management (e.g., flow augmentation, defining flow requirements for spawning, assessing impacts of reservoir operations on early life stages); ii) water quality (e.g., impacts of dissolved gas on larval stages, turbidity augmentation to reduce predation on eggs and larvae, impacts of low water temperatures on early life stages); iii) contaminants (e.g., identify all sources in the Columbia River, assess concentrations in sturgeon and habitats, assess physiological effects on growth, survival and reproduction); iv) habitat (e.g., largescale changes in habitat associated with basin development, feasibility of restoring habitats, passage, increasing productivity); and v) population assessment (e.g., continued stock assessment/spawn monitoring/juvenile assessment, assess other remnant populations, recruitment bottlenecks, genetic baseline, disease/parasites). |
| Inventory Needs: | Inventory of this population has been on-going since the early 1990's. The UCRWSRI (2002) indicated that continued assessment of the adult stock, as well as yearly spawn monitoring and juvenile indexing is necessary for the recovery of this population. |
| Stewardship | |
| Protection: | |
| Management: | 1) Existing restrictions on commercial and recreational fishing. 2) Monitoring and enforcement of illegal harvest. 3) Water management and modifications of river regulation by dams and impoundments. 4) Remediation of pollution sources. 5) Control of exotics and prevention of introductions. 5) Conservation aquaculture (in progress by UCRWSRI). 6) Monitoring of population status, critical habitats and threats. (Fisheries and Oceans Canada 2004). |
| Version | |
| Author: | P. Woodruff, L.M. Porto and L. Ramsay |
| Date: | April 24, 2018 |
| References | |
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COSEWIC. 2012f. COSEWIC assessment and status report on the White Sturgeon Acipenser transmontanus in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xxvii + 75 pp.
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Fisheries and Oceans Canada. 2004. Species at Risk Act. Legal Listing Consultation Workbook. Online. Available: http://www-comm.pac.dfo-mpo.gc.ca/pages/consultations/sara/workbook_fall_e.htm
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Golder Associates Ltd. 2003c. Upper Columbia River: White Sturgeon Population Dynamics Analysis. Rep. prepared for Upper Columbia River White Sturgeon Recovery Initiative. Castlegar , BC. Golder Report No. 031480023D: 41pp.+ 3app. (In prep.)
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Golder Associates Ltd. 2004. Upper Columbia White Sturgeon Stock Monitoring and Data Management Program: 2003 - 2004 Annual Report. Rep. prepared for Minist. Water, Land, and Air Prot., Nelson, BC. Golder Report No. 03-1480-078F: 15pp.+ 3app.
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Golder Associates Ltd. 2005. A synthesis of white sturgeon investigations in Arrow Lakes Reservoir B.C., 1995 - 2003 Draft Report. Prepared for BC Hydro, Castlegar, BC. Golder Report No. 041480016D: 27pp.+ 4app. (In prep.)
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R.L. & L. Environmental Services Ltd. 2000. White Sturgeon Investigations in Arrow Reservoir and Columbia River, B.C. 1999 Study Results. Rep. prepared for Minist. Environ., Lands and Parks, Nelson, BC. R.L. & L. Report No. 754F: 38pp.+ 4app.
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R.L. & L. Environmental Services Ltd. 2001. Columbia River White Sturgeon Spawning Studies, 2000 investigations. Rep. prepared for Minist. Environ., Lands and Parks, Nelson, BC. R.L. & L. Report No. 853F: 24pp. + plates + 2app.
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Upper Columbia White Sturgeon Recovery Initiative (UCWSRI). 2002. Upper Columbia White Sturgeon Recovery Plan. Columbia Basin Fish and Wildlife Compensation Program, BC Hydro, B.C. Gov. 90pp.
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Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.
Suggested Citation:
B.C. Conservation Data Centre. 2018. Conservation Status Report: Acipenser transmontanus pop. 2. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jan 24, 2025).