White sturgeon (Acipenser transmontanus) recovery strategy: chapter 6

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8.6 Kootenay River Population

The Kootenay River population of white sturgeon extends from Kootenai Falls, Montana, located 50 river-kilometres downstream of Libby Dam (Idaho, U.S.), through Kootenay Lake to Corra Linn Dam on the lower West Arm of Kootenay Lake, British Columbia.  Spawning habitat is located in the U.S., and affected by the presence and operation of the Libby Dam, whereas much of the adult and juvenile rearing habitat is located in the Canadian portion of Kootenay River plus Kootenay Lake (e.g. Kootenay delta and tributary creek mouths).  Off channel wetland habitat is likely valuable for early life stages, and historically was in greater abundance than at present.  The transboundary nature of the Kootenay River population requires that recovery efforts be coordinated across multiple jurisdictions.  Recovery of this population will require critical habitats to be designated and managed in both countries in a coordinated manner.

The information base for the Kootenay River white sturgeon population is substantial, based on many years of intensive study, although relatively more information is available for habitats in the U.S. than in Canada.  High use habitats within the Canadian portion of its range have been identified for all life stages, and this information is summarized in Table 17.  As additional information is collected, it will become possible to refine critical habitat designations.

Table 17. Summary of information base for white sturgeon critical habitats in the Kootenay River. A blank cell means that the life stage does not consistently use the habitat. The table has two main columns from left to right: Location (see Figure 36 for basin overview) and Confirmed (Checkmark), Suspected (S), or Possible (question mark) Use by Life Stage and Degree of Use (H=High, M=Moderate, L=Low, U=Unknown). The latter column has seven sub-columns from left to right: Spawn, Yolk sac larvae/feeding larvae, Early juvenile, Late Juvenile and Adult, Overwintering, Staging, and Overall assessment. Directly below column headings are four rows, read from left to right.

Row 1: Lower Kootenay River, empty cell, S (U), checkmark (M), checkmark (M), checkmark (M), checkmark (M), Critical. Row 2:  Kootenay River Delta, empty cell, question mark (U), checkmark (H), checkmark (H), checkmark (H), checkmark (M), Critical. Row 3: Duncan Delta on Kootenay Lake, empty cell, empty cell, S (L), checkmark (H), checkmark (M), checkmark (L), Critical. Row 4: Crawford Creek Delta on Kootenay Lake, empty cell, empty cell, checkmark (L), checkmark (M), checkmark (M), checkmark (L), Critical.

Confirmed (√), Suspected (S), or Possible (?) Use by Life Stage and Relative Density (H=High, M=Moderate, L=Low, U=Unknown)

8.6.1 Biophysical Functions, Features and Attributes of Critical Habitat – Kootenay River Population

Table 18 summarizes the critical habitat function(s), features and attributes, to the extent possible, for the Kootenay River population of white sturgeon.

Table 18. This table provides a summary of the biophysical features, functions, attributes and locations of critical habitat for Kootenay River white sturgeon. The first column describes the geographic locations of the critical habitat, which encompass areas within the Kootenay River system where white sturgeon reside. The second column indicates the life stage that uses each respective critical habitat area. The third column indicates the function that the particular life stage undertakes in each area. The fourth column describes the critical habitat feature that provides the function, and the fifth column details the attributes that the critical habitat feature must have in order to provide the biological function needed to support Kootenay River white sturgeon survival or recovery. The final column contains notes.

*Depositional area– typically lower velocity areas where fish can rest and prey species may congregate; often in close proximity to confluences with other water bodies providing further access to food sources

8.6.2 Geographic Identification of Critical Habitat – Kootenay River Population

The following locations of the critical habitat’s functions, features and attributes have been identified using the critical habitat parcel approach.

Figure 36.  Reference map for locations of Kootenay River white sturgeon critical habitats.

Figure 36.  Figure 36 is a map of Kootenay Lake and portions of the Kootenay River showing an overview of critical habitat locations. Critical habitat includes aquatic habitat features and attributes that Kootenay River white sturgeon use to carry out life functions. Four locations between Meadow Creek and Creston are labelled on the map as follows: Duncan Delta, Crawford Creek Delta, Kootenay River Delta, and Kootenay River. The coordinates denoting various points of the critical habitat boundaries are listed in Table 19. A scale and legend are provided along with an inset map showing locations are primarily in the Kootenay region of British Columbia. The map is oriented in a “north is up” direction.

Figure 37.  Map of critical habitat for Kootenay River white sturgeon: Kootenay River Delta and Lower Kootenay River.

Figure 37. Figure 37 is a map of a section of the Kootenay River, British Columbia, showing the critical habitat locations Kootenay River Delta and Lower Kootenay River. The map depicts two polygons that have been identified as critical habitat for Kootenay River white sturgeon. In the identified polygons, critical habitat includes aquatic habitat features and attributes that Kootenay River white sturgeon use to carry out life functions. The coordinates denoting various points of the polygons’ boundaries are listed in Table 19. The critical habitat polygons in the Kootenay River Delta and Lower Kootenay River map are also labeled with codes that correspond to codes used to identify the polygons in Table 19. A scale of 1:75,000 and legend are provided along with an inset map showing locations are primarily in the Kootenay region of British Columbia. The map is oriented in a “north is up” direction.

Figure 38.  Map of critical habitat for Kootenay River white sturgeon: Duncan Delta on Kootenay Lake.

Figure 38. Figure 38 is a map of a section of Kootenay Lake, British Columbia, showing the critical habitat location Duncan Delta on Kootenay Lake. The map depicts a polygon that has been identified as critical habitat for Kootenay River white sturgeon. In the identified polygon, critical habitat includes aquatic habitat features and attributes that Kootenay River white sturgeon use to carry out life functions. The coordinates denoting various points of the polygon’s boundary are listed in Table 19. The critical habitat polygon in the Duncan Delta on Kootenay Lake map is also labeled with codes that correspond to codes used to identify the polygon in Table 19. A scale of 1:18,000 and legend are provided along with an inset map showing locations are primarily in the Kootenay region of British Columbia. The map is oriented in a “north is up” direction.

Figure 39.  Map of critical habitat for Kootenay River white sturgeon: Crawford Creek Delta on Kootenay Lake.

Figure 39. Figure 39 is a map of a section of Kootenay Lake, British Columbia, showing the critical habitat location Crawford Creek Delta on Kootenay Lake. The map depicts a polygon that has been identified as critical habitat for Kootenay River white sturgeon. In the identified polygon, critical habitat includes aquatic habitat features and attributes that Kootenay River white sturgeon use to carry out life functions. The coordinates denoting various points of the polygon’s boundary are listed in Table 19. The critical habitat polygon in the Crawford Creek Delta on Kootenay Lake map is also labeled with codes that correspond to codes used to identify the polygon in Table 19. A scale of 1:30,000 and legend are provided along with an inset map showing locations are primarily in the Kootenay region of British Columbia. The map is oriented in a “north is up” direction.

Table 19. Geographic Coordinates of Critical Habitat Areas for Kootenay River white sturgeon. A footnote on the word “coordinates” in the previous sentence states the following: Coordinate points were digitized using various orthophotos provided by Fisheries and Oceans Canada. The resolution of the various orthophotos varied significantly - ranging from 0.2 m cell size to 24 m cell size. This should be taken into consideration when evaluating the accuracy of the coordinates associated with these points. For geographic coordinate points, their boundary represents the annual high water mark (Hatfield et al. 2012), except where otherwise noted for the Kootenay River population where the areal extent is 533 m elevation at the extreme south end of Kootenay Lake to a depth of 100 m (the transition from depositional delta to regular lake bottom). This area includes the Kootenay River downstream from the CP train bridge near rkm 122. Note: For the Kootenay River, relative locations are measured as “river kilometers”, which increase from the river mouth (Rkm 0) upstream to the farthest extent possible.

The table has eight columns read left to right: Critical Habitat Name, Coordinate Marker, Waterbody, River Kilometer, Latitude (DD), Longitude (DD), Latitude (DMS), Longitude (DMS). DD refers to Decimal Degrees and DMS refers to Degrees, Minutes, Seconds. Directly below the column headings there are 35 rows. Four rows correspond to the Kootenay – Crawford Creek Delta on Kootenay Lake area, 20 to the Kootenay – Duncan Delta on Kootenay Lake area, and 11 to the Kootenay – Kootenay River Delta and Lower Kootenay River area.

8.7 Activities Likely to Result in the Destruction of Critical Habitat

Under SARA, critical habitat must be legally protected from destruction within 180 days of being identified in a recovery strategy or action plan.  For white sturgeon, it is anticipated that protection will be accomplished through a SARA Ministerial Order made under subsections 58(4) and (5), which will engage the prohibition under s.58(1) of SARA against the destruction of critical habitat¹⁵.  It is important to keep in mind that critical habitat can be destroyed from activities both within and outside of its geographic extent.  

The activities described in this section are neither exhaustive nor exclusive and have been guided by the threats in section 4. The absence of a specific human activity does not preclude the department’s ability to regulate it pursuant to SARA. Furthermore, the inclusion of an activity does not necessarily result in its prohibition.  The prohibition against the destruction of critical habitat is engaged if a critical habitat protection order is made.  Also, activities that impact critical habitat but do not result in its destruction are not prohibited. Since habitat use is often temporal in nature, every activity is assessed on a case-by-case basis and site-specific mitigation measures are applied where they are reliable and available. In every case, where information is available, thresholds and limits are associated with attributes to better inform management and regulatory decision-making. However, in many cases the knowledge of a species and its critical habitat may be lacking. In particular, information associated with a species’ or habitat’s threshold of tolerance to disturbance from human activities is lacking and must be acquired.

For each population of white sturgeon, known critical habitat threats have been assessed to provide examples of activities likely to result in the destruction of critical habitat and are summarized below.

8.7.1 Upper Fraser River Population

Activities that could destroy critical habitat for the Upper Fraser population include instream activities such as gravel or sand dredging, linear developments, riparian alterations or developments to instream or adjacent habitats, and upstream land and water uses.  There is concern around the cumulative impact of sedimentation, habitat fragmentation and works that may cumulatively impact food supply.  There are also unknowns about juvenile habitat use that make these impacts potentially significant.  Changes to the habitat as a result of pine beetle deforestation will need to be carefully monitored for impacts to sturgeon life functions, though complete mitigation in this case may not be possible.

Table 20. Activities likely to destroy critical habitat for the Upper Fraser River population. The table has five columns read from left to right as follows: Threat, Activity, Effect – Pathway, Function Affected, and Thresholds / Range / Qualitative Characteristics of the CH feature and Attribute beyond which the activity could negatively impact the function such that destruction of CH is likely; this last column has two sub-headings: Feature Affected, and Attribute Affected. The Threat column lists the nature of the threat to critical habitat. The Activity column lists individual activities that may result in a threat. The Effect – Pathway column details the mechanisms through which a particular activity results in a threat to critical habitat. The Function Affected column lists which functions of critical habitat are threatened by a particular activity. The remaining two sub-headings (Feature Affected and Attribute Affected) describe the thresholds, ranges, and qualitative characteristics of features and attributes of critical habitat that are threatened by a particular activity.

*Depositional area– typically lower velocity areas where fish can rest and prey species may congregate; often in close proximity to confluences with other water bodies providing further access to food sources

8.7.2 Nechako River Population

There are several activities that could destroy critical habitat in the Nechako system.  River regulation is believed to have had a significant influence on habitat quality at the spawning site, in particular by removing peak flows from the system.  This has led to less frequent flooding of gravel bars, increased vegetation on bars and islands, and generally less movement of stream substrates (with concomitant decrease in substrate suitability for white sturgeon).  Other activities such as gravel or sand dredging, linear developments, riparian, foreshore, floodplain alterations or developments, upstream land and water uses, and point and non-point source effluent discharges are possible concerns for all critical habitats in the watershed depending on details of the activities. 

There is concern around the cumulative impact of sedimentation, habitat fragmentation and works that may cumulatively impact food supply.  There are also unknowns about juvenile habitat use that make these impacts potentially significant.  Changes to the habitat as a result of pine beetle deforestation will need to be carefully monitored for impacts to surgeon life functions, though complete mitigation in this case may not be possible. 

Federal and Provincial agencies continue to work with hydroelectric operators to mitigate impacts to sturgeon and balance residual impacts where possible.  Continued co-operation and monitoring of impacts from river regulation are required.

Table 21. Activities likely to destroy critical habitat for the Nechako River population. The table has five columns read from left to right as follows: Threat, Activity, Effect – Pathway, Function Affected, and Thresholds / Range / Qualitative Characteristics of the CH feature and Attribute beyond which the activity could negatively impact the function such that destruction of CH is likely; this last column has two sub-headings: Feature Affected, and Attribute Affected. The Threat column lists the nature of the threat to critical habitat. The Activity column lists individual activities that may result in a threat. The Effect – Pathway column details the mechanisms through which a particular activity results in a threat to critical habitat. The Function Affected column lists which functions of critical habitat are threatened by a particular activity. The remaining two sub-headings (Feature Affected and Attribute Affected) describe the thresholds, ranges, and qualitative characteristics of features and attributes of critical habitat that are threatened by a particular activity.

8.7.3 Upper Columbia River Population

Activities that could destroy critical habitat for juvenile and adult life stages include: several aspects of river regulation (impoundment operations and load-following (i.e. adjusting power output to meet daily demand fluctuations)); gravel or sand dredging; linear developments; riparian, foreshore, floodplain alterations or developments; upstream land and water uses; and point and non-point source effluent discharges.  The exact concerns vary depending on details of the activities and their location within the Columbia drainage. 

There is some concern around the cumulative impact of sedimentation, habitat fragmentation and works on ecosystem pathways and trophic interactions.  There are also unknowns about juvenile habitat use that make these impacts potentially significant. 

Federal and Provincial agencies continue to work with hydroelectric facilities to mitigate impacts to sturgeon and balance residual impacts where possible.  Continued co-operation and monitoring of impacts from river regulation are required.

ALR component -- The spawning site for the ALR component is downstream from REV Dam, which is currently operated as a load-following facility.  There is the possibility that operations of REV Dam may influence the viability of incubation habitat by dewatering eggs, particularly in years of low reservoir levels at Arrow Lakes.  Hypolimnetic releases (i.e., from deep, cold water) from upstream dams are thought to have contributed to altered water temperatures and are believed to influence timing of spawning and duration of embryo development.  Elevation of ALR is believed to alter channel depth and velocity parameters below REV Dam due to a backwatering effect, which may influence suitability of spawning and incubation habitats.

Operations at REV Dam prior to unit 5 coming online in December 20, 2010 may have limited connectivity among habitats from ALR to the spawning site adjacent to the Revelstoke golf course during minimum flow periods.  Since the addition of unit 5 the minimum flow at REV Dam has gone from 8.5m³/s to 142m³/s increasing total wetted riverbed area by 37%; monitoring is ongoing to determine improvements in habitat connectivity as well as hydraulic properties within incubation and early rearing habitats (James Crossman, B.C. Hydro, personal communication). River regulation is managed to ensure that flow changes are implemented to minimize stranding risk to native species. These ramping rates have been determined through extensive research (e.g. Irvine et al. 2008) and are modified as needed through ongoing monitoring programs.

Transboundary component -- The Waneta spawning area is influenced by load-following and water storage associated with a series of dams on the Pend d’Oreille River, primarily within facilities in the U.S., but including Seven Mile and Waneta Dams within Canada.  There are restrictions on load-following currently in place during the spawning season to address this threat.  Spawning occurs primarily beyond the Pend d’Oreille River channel, into the confluence with the Columbia River mainstem and downstream a short distance.  Thus, upstream storage dams on the Columbia and Kootenay rivers may influence spawning and incubation habitats in the Waneta area, although the consequences have been limited.  Backwater influence from Lake Roosevelt in the U.S. does not reach upstream to these habitats, but may influence downstream rearing habitat.  Contaminant impacts are of concern primarily in the U.S. portion of the river (this was rated low in Canada). 

*Depositional area– typically lower velocity areas where fish can rest and prey species may congregate; often in close proximity to confluences with other water bodies providing further access to food sources

8.7.4 Kootenay River Population

Activities that could destroy critical habitat for the Kootenay River population include flow regulation, instream activities such as gravel or sand dredging, linear developments, alterations or developments to instream and adjacent habitats, and upstream land and water uses. 

There is concern around the cumulative impact of sedimentation, habitat fragmentation and works that may cumulatively impact food supply.  There are also unknowns about juvenile habitat use that make these impacts potentially significant. 

Federal and Provincial agencies continue to work with hydroelectric facilities to mitigate impacts to sturgeon and balance residual impacts where possible.  Continued co-operation and monitoring of impacts from river regulation are required.

Table 23. Activities likely to destroy critical habitat for the Kootenay River population. The table has five columns read from left to right as follows: Threat, Activity, Effect – Pathway, Function Affected, and Thresholds / Range / Qualitative Characteristics of the CH feature and Attribute beyond which the activity could negatively impact the function such that destruction of CH is likely; this last column has two sub-headings: Feature Affected, and Attribute Affected. The Threat column lists the nature of the threat to critical habitat. The Activity column lists individual activities that may result in a threat. The Effect – Pathway column details the mechanisms through which a particular activity results in a threat to critical habitat. The Function Affected column lists which functions of critical habitat are threatened by a particular activity. The remaining two sub-headings (Feature Affected and Attribute Affected) describe the thresholds, ranges, and qualitative characteristics of features and attributes of critical habitat that are threatened by a particular activity.

*Depositional area– typically lower velocity areas where fish can rest and prey species may congregate; often in close proximity to confluences with other water bodies providing further access to food sources

8.8 Schedule of Studies to Identify Critical Habitat

Further research is required to identify and/or refine additional critical habitat necessary to support the species’ population and distribution objectives and protect critical habitat from destruction. This additional work includes the following studies and is directly related to the Recruitment Failure Hypothesis.

Critical habitats defined in this document, when combined with functioning recruitment in each population, should be sufficient for survival and provide a solid basis for population recovery.  While it is possible that additional habitat may be required for recovery of the species, it is not known at this time.  The principle limitation to recovery is the functionality of currently identified habitats rather than their spatial extent. This focus is reflected in the knowledge gaps identified in the recovery strategy, which provides a guide to future studies with a strong focus on recruitment failure diagnosis and restoration.  As a result, studies identified here emphasize understanding habitat functionality and recruitment restoration within critical habitats. While studies of the species biology and movement may provide further information on definition of particular critical habitats, such studies should not supersede investigations of recruitment failure and its restoration because doing so may not be in the best interest of the species.

Table 24. Schedule of Studies to identify critical habitats. The table has four column headings read from left to right: Population(s), Description of Study, Rationale, and Timeline. A footnote on the heading “Timeline” states the following: The timelines denoted here represent an estimation of how long each study would take in years. Since some studies are dependent on others, or on specific hydraulic or biological conditions being present, the timelines provided do not specific start and end dates. Flexibility to undertake studies opportunistically as conditions allow should be maintained.

Directly below the column headings are six rows, read from left to right.

Row 1: Upper Columbia, Confirm use of the Kinnaird area of Columbia River by spawning adults, identify egg and larval rearing habitats, and describe habitats used by juveniles and adults for feeding and overwintering. Larval captures have been recorded at this site consistently in the last several years, as well as uses by other life stages. Specific locations that are being utilized for spawning are not well understood at this time, 3 years. Row 2: Upper Columbia, Nechako, Upper Fraser populations, Confirm locations of spawning sites. Not all spawning locations are currently known or confirmed, 3 years. Row 3: All SARA listed populations*, Initiate lab and/or in situ studies to investigate habitat use by eggs (e.g. survival), yolk sac larvae (e.g. survival), and feeding larvae (e.g. cover, and food availability). Eggs/yolk sac larvae - interstitial habitats are beneficial, micro habitat use requires further study Feeding larvae - habitat use by feeding larvae is highly uncertain *Only yolk sac and feeding larvae studies would be undertaken for Kootenay River white sturgeon, because spawning occurs outside Canada, 2-4 years, contingent on having enhanced Substrate placed and having appropriate river conditions. Row 4: Upper Columbia, Nechako populations, Undertake pre-requisite studies in support of spawning habitat restoration. Investigate hydraulic conditions required to sustain preferred incubation substrates, To better understand substrate preferences that determine habitat selection, 4-5 years. Row 5: Upper Columbia, Nechako populations, Investigate biological determinants of spawning micro habitat selection. This would include evaluation of physical conditions (e.g. hydraulics), social/chemical cues (e.g. presence of other fish, pheromones), as well as investigation of manipulating habitat attributes to attract/deter spawning at specific locations, To better understand substrate preferences that determine habitat selection, 4-5 years, contingent upon spawning cycles. Row 6: Upper Columbia, Initiate experimental spawning habitat restoration (one location minimum) in the Transboundary reach, Suggested for the Transboundary reach of the Upper Columbia because experiments already initiated for the Nechako Population, and for the Revelstoke reach of the Upper Columbia. Kootenay white sturgeon spawning habitat is not in Canada, 4-5 years.

¹⁴ Coordinate points were digitized using various orthophotos provided by Fisheries and Oceans Canada. The resolution of the various orthophotos varied significantly - ranging from 0.2 m cell size to 24 m cell size. This should be taken into consideration when evaluating the accuracy of the coordinates associated with these points. For geographic coordinate points their boundary represents the annual high water mark (Hatfield et al. 2012), except where otherwise noted for the Kootenay River population where the areal extent is 533 m elevation at the extreme south end of Kootenay Lake to a depth of 100 m (the transition from depositional delta to regular lake bottom). This area includes the Kootenay River downstream from the CP train bridge near rkm 122.
Note: For the Kootenay River, relative locations are measured as “river kilometers”, which increase from the river mouth (rkm 0) upstream to the farthest extent possible.

¹⁵ In the critical habitat area for Nechako River White Sturgeon, “Vanderhoof Braided Section” (Figure 15), it is anticipated that the critical habitat occurring within the Nechako Migratory Bird Sanctuary will be protected following publication of a description of the area pursuant to subsection 58(2) of SARA. Critical habitat areas in the Vanderhoof Braided Section that occur outside of the Nechako Migratory Bird Sanctuary will be protected through the SARA Ministerial Order described above.

¹⁶ The timelines denoted here represent an estimation of how long each study would take in years. Since some studies are dependent on others, or on specific hydraulic or biological conditions being present, the timelines provided do not specific start and end dates. Flexibility to undertake studies opportunistically as conditions allow should be maintained.