White sturgeon (Acipenser transmontanus) recovery strategy: appendix B

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Appendix B: Recovery of Middle and Lower Fraser River White Sturgeon Populations and Important Habitats

Note: The Lower and Middle Fraser white sturgeon populations were assessed by COSEWIC as Endangered in 2003, but were declined for SARA listing in 2006. As such, SARA does not apply to these populations, and they are not subject to the automatic prohibitions or requirement to identify critical habitat. Relevant recovery information for these populations is included as an appendix to the Recovery Strategy to provide a comprehensive picture of white sturgeon conservation in British Columbia.

1. Recovery of Middle and Lower Fraser Populations¹⁷

1.1 Recovery Objectives

The following recovery objectives apply to the middle and lower Fraser River populations of white sturgeon:

1. Prevent extirpation of white sturgeon in each of the identified populations by ensuring no net loss of reproductive potential.
2. Reach or exceed the following population and distribution targets for conservation within 50 years:
   1. 10,000 mature individuals in the lower Fraser River;
   2. current mature individuals in the middle Fraser River;
   3. approximately 1:1 sex ratio at maturity;
   4. distribution over the natural range;
   5. natural age structure;
   6. natural recruitment in the lower Fraser River sufficient to meet goal (a);
   7. maintain current levels of natural recruitment in middle Fraser River;
3. Determine the current levels of beneficial use through the FSC and commercial salmon gillnet and beach seine fisheries, and in the catch and release recreational fishery.  Maintain current levels of beneficial use provided they do not threaten population recovery as indicated above.
4. Reach or exceed population and distribution targets for expanded beneficial use within specified timeframes.  As success is achieved in meeting the biological recovery targets, the beneficial use targets and timelines will be established and adjusted.  Such targets may vary among populations.

1.2 Recovery Population Targets

The recovery strategy proposes the following targets for long-term population viability as defined in the Recovery Population Targets section of the Recovery Strategy.  As new information becomes available these targets may be updated.  The targets are considered sufficient for ongoing recovery planning of white sturgeon over the next 10 years.

1.2.1 Abundance

An interim abundance target of 10,000 mature individuals is proposed for the lower Fraser River population and a target of current abundance is proposed for the mid-Fraser River.  Mature is defined as 1.6 metres fork length or 18-20 years of age.  These abundance targets are higher than for the four listed populations, although for the lower Fraser River in particular the habitat carrying capacity is much greater than in other areas.  Based on the available scientific literature these targets are believed sufficient to meet abundance criteria to offset threats from demographic, environmental and genetic changes over the next 100 years.  Because genetic variation in these populations is poorly understood it is assumed that this will be adequate given the long generation time (~ 40 years) and the planning time frame considered here.  However, these abundance targets provide little protection against environmental catastrophes or significant increases in beneficial use.  It should be noted also, that the current population estimate for the mid-Fraser River is weak, and needs to be improved to support the abundance target.

1.2.2 Population Growth Rate

Natural populations fluctuate in abundance, which can make trends difficult to detect over the short term.  The target is continued growth in all populations over the long-term when populations are below the target abundance level.  The following growth rate targets are proposed:

• continued natural recruitment level in the middle Fraser River;
• natural recruitment in the lower Fraser River that allows population targets to be achieved;
• maintenance of at least the present abundance for all age classes in the middle Fraser River populations; and,
• increasing abundance for all age classes in the lower Fraser River population in order to meet population targets.

1.2.3 Population Structure

The following targets for population structure are proposed:

• distribution across the populations’ natural range;
• natural sex ratio (currently defined as 1:1); and,
• natural age structure.

The stable age distribution should be highly skewed, with the majority of individuals in immature age classes.

1.2.4 Population Diversity

To understand historic and current sub-populations and their associated habitats, to protect important habitats and where possible restore habitats required for population maintenance or recovery.

1.3 Approaches to Meeting Recovery Objectives for Middle and Lower Fraser River Populations

Table B-1. Recommended strategies to meet management objectives for non-SARA-listed populations. The table has four columns read from left to right: Priority, Strategy, Actions, Performance Measure. Directly below column headings are seven rows read from left to right as follows.

Row 1: Necessary, Meet or exceed population targets within specified timeframe, 1. Monitor population trends. 2. Establish parameters for beneficial use. Have targets been achieved? Row 2: Necessary, Protect important habitats, 1. Identify habitat requirements for major life stages. 2. Define important habitats (including related ecological processes). 3. Protect, maintain and enhance important white sturgeon habitats. 4. Ensure habitat diversity, connectivity & productivity. 5. Ensure coordination between regulatory agencies with jurisdiction over white sturgeon habitat. Has important habitat been defined? Have important habitats been protected? Row 3: Necessary, Clarify, manage and mitigate threats, 1. Clarify the following threats and their relative risks: a. Directed and non-directed fishing, b. pollution, c. food supply, d. habitat. 2. Undertake specific actions to manage risks: a. protect, maintain and enhance important habitats, b. manage illegal harvest, c. mitigate impacts from fisheries through regulation and best practices, d. limit and manage pollutant discharges and contaminant loading, especially adjacent to important habitats, e. protect, maintain and enhance water quality, f. manage and mitigate the growth of commercial sturgeon aquaculture, g. better understand, maintain and enhance food availability for all life stages of each population. 3. Monitor threat indicators and population trends. 4. Clarify regulatory roles and responsibilities of agencies with jurisdiction over threats to white sturgeon and their habitats; Have the threats been clarified? Have the regulatory roles and responsibilities been clarified? Have the threats been sufficiently managed or mitigated? Row 4: Primary, Address information gaps that inhibit conservation of white sturgeon. 1. Address study needs to define important habitats (see Appendix A for the Studies to Address Knowledge Gaps). 2. Address basic biological data gaps (see Section 7: Knowledge Gaps in the Recovery Strategy for discussion of data gaps), Have information gaps been filled? Row 5: Primary Increase stakeholder and general public awareness of white sturgeon and its conservation needs. 1. Increase awareness and stewardship of white sturgeon throughout its natural range. 2. Engage in effective public education of the species and its conservation needs. 3. Support learning and communication across all working groups. 4. Ensure participation from community and technical experts. Has general awareness of sturgeon conservation been achieved? Row 6: Secondary, Maintain and where necessary restore ecosystem functions relevant to white sturgeon, 1. Incorporate the needs of healthy white sturgeon populations into the management of white sturgeon prey species including salmon, eulachon, and resident fish. 2. Accommodate other species’ needs during recovery of white sturgeon. 3. Manage non-native predatory fish species to reduce impacts to white sturgeon. 4. Coordinate with regulatory agencies that have influence or jurisdiction over white sturgeon prey species. Is the ecosystem “healthy” for white sturgeon? Row 7: Secondary, Implement the recovery strategy, 1. Protect the species with existing legislation. 2. Secure funding for implementation of recovery actions. 3. Update and revise the strategy at least every 5 years. Has the recovery strategy been updated as needed?

2. Important Habitats for Lower and Middle Fraser River White Sturgeon Populations in British Columbia, Canada

2.1 Introduction

2.1.1 Purpose

With the inclusion of the non-SARA listed middle and lower Fraser River white sturgeon populations to the recovery strategy it was decided by the Recovery Team that important habitats for these populations should be identified and included in the strategy.  To undertake this evaluation, a summary of current knowledge about the freshwater habitat that is important to the survival or recovery of each population is required.

The purpose of this section is to review existing information relevant to the determination of important habitat for white sturgeon in each of the two non-SARA listed populations.  This section introduces the concept of important habitat as it relates to the non-SARA listed populations and summarizes existing information about the location, extent, current status, and potential threats to freshwater habitat that is important to survival and recovery of white sturgeon in the non-SARA listed populations in Canada.  This section provides sources of information, reliability of the information, and provides a brief discussion of data gaps.  The document also includes maps to indicate the geographic areas containing important habitat features.  Much of the information on white sturgeon in the section comes from main body of the National White Sturgeon Recovery Strategy.

Though the important habitat identified for the non-SARA listed populations of white sturgeon in B.C. has no legal meaning or bearing under SARA it can be used to guide decisions by various parties including regulatory agencies. The document will provide an initial direction to users on potential impacts to specific habitat types, additional habitat or sturgeon use assessment needs, and potential mitigation activities needed to avoid impacts to habitats, to population recovery potential or to individual sturgeon.  Fisheries and Oceans Canada (DFO) may use the section to inform decisions on habitat management within the area.

2.1.2 Important Habitat

Identification of habitats that are required to complete necessary life stages is vital for the management of species in decline, and is one of the most challenging aspects of their management.  Despite its complexity, the core issue is the same for all species: to determine the role of habitat in population limitation, and to answer the question, “How much habitat, and of what type, is required to maintain or restore viable populations of the species?”

Important habitat for non-SARA listed individuals can be defined as habitat that is required to complete essential life stages and that may play a key role in the maintenance, survival or recovery of the species.  Important habitat designation includes geographic areas as well as habitat features such as water quality, large woody debris associations, spawning habitat qualities etc. It is distinct from ‘critical habitat’, which is legally identified for SARA-listed populations only

To complement this definition, Rosenfeld and Hatfield (2006) suggest several practical working definitions that provide general guidance and screening criteria for evaluating potentially important habitats.

1. Habitat that is disproportionately important.  The litmus test is whether loss of a particular habitat unit will result in significant population level effects for a population at the abundance level of the recovery target.  This emphasizes prioritization of habitat protection based on the population consequences of habitat loss or gain, with the understanding that if a particular habitat unit can be lost without population level effects, it is unlikely to be critical. 
2. The minimum subset of habitats required for a species or population to persist.  This emphasizes that the default objective may not be to protect the entire range of a species, and that for some species different configurations or subsets of habitat of varying quality may ensure species persistence.
3. Habitats that are necessary to maintain ecosystem integrity and function.  This emphasizes that discrete habitat patches must function “properly,” and processes that influence habitat quality must be maintained (e.g., river flooding, riparian buffer, etc.).

2.2 General Approach

A reasonable approach to determine important habitat for a species in decline is to consider the amount and type of habitat required for the species to persist and recover.  At present it is not possible to complete a quantitative relationship between habitat and population size due to a lack of data. The lower and mid-Fraser River populations represent somewhat different conditions than the SARA listed populations.  In the mid-Fraser River the population is near its historic level, and relative to the Upper Fraser River the higher population offers greater resilience.  The lower Fraser River on the other hand has the highest population in the province and the largest available habitat area, including the marine environment.  As such, the default assumption that present habitat use is the best indicator of a minimum set of habitats required into the future may not be as appropriate in these two cases.  Despite this, and because of the lack of data to pursue alternate approaches, this same assumption was used to define important habitats for the lower and mid-Fraser River populations.  To the extent feasible, habitat delineations were based on habitat associations developed from detailed empirical work.  Current data limitations suggest that additional important habitats may be identified with further information.

Some of the important habitats proposed here encompass large areas of the Fraser River.  In part this reflects the variety of habitats used by this species, and its extensive movements.  However, it is also important to note that the proposed definition of large areas also results from the significant uncertainty in our understanding of habitat use.  The large spatial area of the lower and mid-Fraser River, and the comparative complexity of the river channel make precise delineation of habitat use more challenging than for other populations.  As such, important habitats proposed here represent a broad delineation of habitats in many cases.  In many cases further assessment will be required in future in order to provide more definitive and accurate delineation of habitats, and habitat features that will be required for species recovery. Further information might define only a subset of habitats within these larger areas.

It should be noted that this document was not peer reviewed and important habitat has no legal meaning or bearing under SARA.

2.2.1 Process

Providing information on important habitat was a separate and discrete task during development of the Recovery Strategy.  The National Recovery Team for White Sturgeon has representation from a number of basin-specific technical and community working groups.  Members of the National Recovery Team were tasked with leading the basin-specific groups through a process to collate and evaluate relevant existing information on critical habitat for the SARA-listed populations, and important habitat for the non-listed populations.  Lee Williston (Ministry of Environment) led the process for the middle Fraser River; and Erin Stoddard (Ministry of Environment) led the process for the lower Fraser River.  They were supported in this role by other National and basin-specific members.  The basin-specific groups were tasked with determining candidate habitats and providing a recommendation for important habitats.  They were asked to document sources of information, reliability of the information, and descriptions of data gaps.  The results of these basin-specific discussions are provided in the following sections.  All background information in this document was assembled during development of basin-specific recovery or conservation plans. 

In addition to deciding which habitats are important the basin groups were required to provide help in defining the boundaries of these habitats.  There is inevitably some subjectivity associated with this task, but it was based on consideration of the available scientific information.  The elevational boundary of important habitats was limited to the annual high water mark.  All boundaries were demarcated on maps.

3. Important Habitats for Non-SARA Listed Populations

3.1 Key Life Stages and Habitat Needs

3.1.1 Early Juvenile Habitat

The early juvenile stage is defined as occurring from hatch to 2 years, and may be broken into two stages as follows:

0 - 21 days -- This is the period from hatch to successful initiation of exogenous feeding.  It includes phases of hiding in interstitial spaces, drift and swim-up, and the initiation of exogenous feeding.  Little is known about this phase in the wild, but it is known to be an important phase for recruitment as larvae are very vulnerable to predation.  These habitats would be closely associated with spawning and incubation habitats.  Current research in the Nechako River indicates that newly hatched sturgeon undergo a hiding phase which lasts until the onset of feeding, so drift for long distances downstream from these habitats is likely limited (Steve McAdam, B.C. Ministry of Environment, personal communication).

21 days to 2 years -- Habitat needs within this 2 year period may be considerably different than in the life stage immediately preceding it.  Information about this age group is limited, however, especially from age 1 year onward they appear to use similar habitats as immature and adult sturgeon.  Recent information indicates that this phase may not use lower estuary or marine habitats, as no juveniles less than 2 years old have been captured downstream of km 10.5 (Glova et al. 2008, 2009).  However, limited sampling in these habitats cannot definitively exclude such use, especially since these areas are used extensively by late juvenile and mature fish.  In general terms Glova et al. (2008, 2009) confirmed that 1+ year old sturgeon appear concentrated in some areas more than others, and that they use similar habitats to adults.  However, no 0+ year old (in their first year) sturgeon have been captured, so the assumed similarity in habitat use for fish less than 1 year old requires further evaluation. 

3.1.2 Late Juvenile and Adult Habitat

The late juvenile and adult stages include fish which are greater than 2 years old, with maturity occurring at approximately 20 years of age.  The lifespan of white sturgeon is likely greater than 80 years so this is a much extended period.  Further research into the life history of the natural middle and lower Fraser River populations including the marine and estuary use in the lower Fraser River may result in this period being further categorized.

2 years to greater than 80 years -- Although the diets of younger fish may be considerably different from those of large adult fish, habitat use during this stage is likely similar.  However, it will depend on the target prey or food, its availability, and the river and/or tidal flow levels and patterns.  In general, individuals in this class occupy similar habitats for the purposes of feeding, holding and likely for overwintering.  Habitat preference differences likely occur between age classes in this group due to competition, significant differences in energetic requirements and expenditures, and associated caloric requirements.  Habitat use during this stage can be separated into five general types as follows:

Overwintering -- Overwintering habitats are typically deeper lower flow areas, which are downstream of salmon spawning tributaries or mainstem areas that would act as carcass depositional areas.  Congregations of sturgeon in these areas are known to be significant, but the size, extent or activity of these congregations has not been delineated due to difficulties with studying these parameters in a large, deep, turbid river.  These congregations have been shown to be very large (tens of thousands) in similar lower Columbia River populations (Michael J. Parsley, United States Geological Survey, personal communication).  Sturgeon typically inhabit these areas throughout the year.  However, congregations appear to be larger during the overwintering period, which starts around the decrease of fall spawning salmon near the middle of December, and ends around the start of spring spawning fish species near the middle of March.  Sturgeon still actively feed during the overwintering period, even when water temperatures are colder in January and February, though their activity levels appear reduced.

Spring Migration & Feeding -- The spring migration starts in association with the beginning of spring spawning prey fish species activity.  During this period, sturgeon likely concentrate on all congregations of spring spawners for food, including trout, catastomids and cyprinids.  In the lower Fraser River, sturgeon concentrate strongly on spring spawning smelt and eulachon, with their initial migration off the overwintering areas closely associated with the start of the upstream migration of spawning eulachon.

Staging & Spawning -- It is unclear to what degree pre-spawning adults participate in the spring migration for feeding or whether they are primarily migrating to pre-spawn staging areas.  However, in the lower Fraser River there is anecdotal and traditional aboriginal knowledge that supports large fish migrating downstream to feed on eulachon near the Fraser River mouth and then migrating upstream out of the area prior to or soon after the start of the spring freshet.  Staging occurs in deep lower flow areas adjacent to spawning habitats.  Sturgeon move onto spawning areas on the falling hydrograph after the peak snow melt freshet.  The timing of spawning is likely somewhat variable, has not been recorded in detail, and is temperature and flow dependent.  However, it appears to occur between the middle of June and the beginning of August.

Early Summer Feeding -- This includes the period from the end of spring spawner feeding to the start of upstream salmon migration.  Sturgeon use is typically associated with spring spawner habitats or carcass depositional areas during this period. The first spawning salmon species to enter the river are early Chinook which starts in May to June, but there appears to be only limited changes in sturgeon migration associated with the upstream movement of this salmon species.  The start of the early sockeye salmon spawning migration at the beginning of July appears to trigger the end of this period when sturgeon start migrating to sockeye spawning rivers or associated carcass depositional areas.

Late Summer & Fall Migration and Feeding -- The start of the early sockeye salmon spawning migration at the beginning of July is associated with the beginning of this period.  In the lower Fraser River, this period lasts well into December as numerous salmon species and stocks are migrating into the rivers to spawn.  In the middle Fraser River, this period is likely less extended due to the reduced number of salmon species and stocks, or other fall spawning fish for sturgeon to target.  During this period, sturgeon movement can be extensive while they feed on different salmon spawning populations, especially in the lower Fraser River.  The habitat use at the end of this period is closely associated with the overwintering habitats, which are often depositional areas for the last fall spawning salmon population.

3.2 Middle Fraser River

In the middle Fraser River, white sturgeon occur from the confluence of the Nechako River at Prince George, downstream to Hell’s Gate canyon, 210 km from the mouth, and at the confluence and lower reaches of major salmon spawning tributaries.  Migration data is limited; however, movement between holding, spawning and feeding areas has been observed and recorded.  Current abundance and distribution in the middle Fraser River is likely limited by habitat and prey availability, which is limited due to higher gradient areas, and by the abundance of migrating sockeye salmon as prey.  The middle Fraser River also likely has significantly lower overall and seasonal productivity than the lower Fraser River due to significant climate differences and fewer anadromous fish species and stocks.  The section upstream of km 674  to the confluence of the Nechako River is believed to have sparse numbers of sturgeon due to even more limited habitat availability, though there are some habitats dispersed throughout this section that are similar to those preferred by sturgeon.  Limited research was conducted through this entire section of the Fraser River through the provincial study in the early 1990s.  However, only limited studies have been conducted through km 410 to km 674 since then.  Some information has been available and is provided here for the section from km 210 to km 410 from the recreational catch and release fishery.  This fishery has been established here for some time, and has been recently expanding.

3.2.1 Spawning and Incubation Habitat

Only two mainstem spawning areas have been identified by radiotracking in the middle Fraser River. One spawning area is at and near the confluence of the Cottonwood River.  However, the precise spawning location changes from year to year depending on substrate and flow conditions. The second spawning area is located approximately 10 kilometres downstream of Hawks Creek. It is suspected through anecdotal information that there are spawning sites downstream of the Hawks Creek site between km 210 and km 500.  However, very few sturgeon studies have been undertaken through this reach of the middle Fraser River.  It is likely that additional spawning and incubation sites will be identified in the future.  Recent studies indicate that in natural habitats, white sturgeon eggs do not drift far, so incubation habitats are assumed to be coincident with spawning habitats.

Important Spawning & Incubation Habitat -- The Cottonwood River and Hawks Creek areas are the only identified spawning areas for middle Fraser River white sturgeon.  This habitat would be deemed important on an annual basis during June and July, based on known timing of spawning and incubation.  This period is sufficient to encompass known annual variability in the onset of spawning.  The degree of certainty in the delineation of important spawning habitat for the Cottonwood River area is rated as high, based on repeated radiotracking of fish to this area during the spawning season. The degree of certainty in the delineation of important spawning habitat for Hawks Creek area is also rated as high, based on tracking of mature radio tagged sturgeon.

These areas are depicted in Figures B-1 and B-2 and are described as:

• Cottonwood River (km 669-674); and,
• Hawks Creek (km 539-542).

The area km 325-332 may also be a potential important spawning and incubation site through repeated use of the area by large sturgeon during the spawning period as identified by recreational angler captures in the area.  The potential spawning area is depicted in Figure B-6 and described as:

• Near the Seton River confluence (km 325-332).

Data Gaps -- There are minor data gaps for determining the geographic boundaries of this important habitat.  However, there are significant gaps in determining similar habitats, particularly downstream of the Williams Creek confluence.  There are also significant uncertainties with respect to the qualities of habitat that are required to maintain this habitat unit function for incubation and early life stages.

3.2.2 Early Juvenile Habitat

0 - 21 days -- See Figures B-1, B-2 and B-6.  Important habitat for this life stage is assumed to include areas within and immediately adjacent to spawning and incubation areas and a short distance downstream as follows:

• Cottonwood River (km 669-674);
• Hawks Creek (km 539-542); and,
• Near the Seton River confluence (km 325-332).

21 days to 2 years -- Habitat needs within this 2 year period may be considerably different than in the life stage immediately preceding it.  It is likely that this stage uses habitat types similar to those preferred by immature and adult sturgeon.

Important Early Juvenile Habitats -- The important habitats for the 0 - 21 days stage are the Cottonwood River confluence and Hawks Creek areas, the same habitat areas noted as important for spawning and incubation.  This habitat would be deemed important on an annual basis during June, July and August, based on suspected timing of spawning and incubation.  This period is sufficient to encompass known annual variability in onset of spawning, hatch and initial rearing.  Important habitat would extend downstream beyond the boundaries of spawning and incubation habitat, but the downstream limit cannot be described at this time.  The degree of certainty in these important habitat determinations is rated as high, based on repeated observations of spawning at the Cottonwood River confluence site and presence of mature radio tagged sturgeon at the Hawks Creek site throughout the time of known spawning, although there is insufficient certainty to define the downstream limit of this habitat beyond that already defined for spawning and incubation.  The km 330-332 site has been offered as a potential spawning, incubation and early rearing site through repeated use of the area by large sturgeon during the spawning period as identified by recreational angler captures in the area.  The degree of certainty for this site is moderate.

Based on the assumed similarity in habitat use by fish aged 21 days to 2 years, the following areas are identified as important:

• Cottonwood River (km 669-674);
• Quesnel River (km 643-645);
• Hawks Creek (km 539-552);
• Chilcotin River (km 475-482);
• Word Creek (km 468-470);
• Grinder and Lone Cabin Creek (km 428-432);
• French Bar Creek (km 408-411);
• km 405-407;
• km 395-401;
• km 368;
• km 350;
• km 320-344;
• km 317-320;
• km 310-315;
• km 282;
• km 273-274; and
• km 250-255.

These areas are reflected in Figures B-1 through B-9.  This habitat would be deemed important throughout the year, based on the assumption of continuous occupation.  The degree of certainty in this important habitat determination is rated as low to moderate, given that they are based on assumed habitat use patterns.

Data Gaps -- There are moderate data gaps for determining the geographic boundaries of this important habitat; river kilometres discussed here are approximate.  These areas defined as important habitat are fairly broad, and are based on existing information of white sturgeon habitat use.  Additional studies may increase the confidence in these boundaries and may permit greater precision in defining the geographic areas of interest. 

3.2.3 Late Juvenile and Adult Habitat

The late juvenile and adult stage is defined as occurring from 2 years onward.  Though feeding requirements and preferences are expected to be quite different, it is expected that in general, all individuals in this class occupy the same habitats for the purposes of feeding and overwintering.

Important Late Juvenile and Adult Overwintering Habitat -- Overwintering habitat of white sturgeon is characterized as habitat where fish can maintain their position with minimal energy use.  These areas are typically also carcass depositional areas for salmon.  The deepest holes in the river are known to be used for overwintering.  The specific locations noted as important overwintering areas are indicated in Figures B-1 through B-5 and include:

• Quesnel River (km 643-645);
• Hawks Creek (km 539-552);
• Chimney Creek (km 520-525);
• Chilcotin River (km 475-482);
• Word Creek (km 468-470);
• Grinder and Lone Cabin Creek (km 428-432); and,
• French Bar Creek (km 408-411).

No overwintering areas have been identified between Hells Gate (km 210) and French Bar Creek (km 408-411) due to current data limitations.

These habitats would be deemed important on an annual basis from November to May, based on known overwintering periods.  The degree of certainty in this important habitat determination is rated as moderate to high, based on radio telemetry and repeated observations of high use areas for overwintering.  Other areas within km 411-470 may also be important habitats for feeding and staging, but additional work is required to support these recommendations. 

Important Adult Staging Habitat -- Middle Fraser River white sturgeon are known to “stage” in specific areas in April, May, June & July prior to spawning.  Recent work observed mature fish staging in several areas from Cottonwood River (km 669-674) (Mike Ramsay, B.C. Ministry of Environment, personal communication).  There are deep holes in this river section used for staging and fish were observed to move frequently throughout adjacent areas. Tracking of radio tagged sturgeon has also identified sites from Hawks Creek (km 539-552) where mature fish were staging. The confirmed important staging areas are indicated in Figures B-1 and B-2, and include:

• Cottonwood River (km 669-674); and,
• Hawks Creek (km 539-552).

In many cases important habitat features for staging are redundant to adult holding and overwintering important habitats identified, as staging fish commonly occupy adult habitats that are used for other purposes prior to migrating to spawning areas. Additional important staging areas could include the following as indicated in Figures B-1, B-3 and B-6:

• Quesnel River (km 643-645);
• Chilcotin River (km 475-482); and,
• Near the Seton River confluence (km 325-332).

Important Late Juvenile and Adult Feeding Habitat -- There doesn’t appear to be a distinct spring migration and feeding stage as in the lower Fraser River.  However, it is known that sturgeon in this area do feed on cyprinids, so it is likely that migrations do occur to cyprinid spawning areas to feed.Feeding habitats are generally similar to overwintering habitat.  Numerous high use areas have been identified for this life stage in the middle Fraser River.  Based on known habitat use, several areas are proposed as important habitats for feeding and include (see also Figures B-1 through B-9):

• Cottonwood River (km 669-674);
• Quesnel River (km 643-645);
• Hawks Creek (km 539-552);
• Chimney Creek (km 520-525);
• Riske Creek (km 485-495);
• Chilcotin River (km 475-482);
• Word Creek (km 468-470);
• Grinder and Lone Cabin Creek (km 428-432);
• French Bar Creek (km 408-411);
• km 405-407;
• km 395-401;
• km 368;
• km 350;
• km 320-344;
• km 317-320;
• km 310-315;
• km 282;
• km 273-274; and
• km 250-255.

These habitats would be deemed important year-round.  The degree of certainty in this important habitat determination is rated as moderate to high, based on radio telemetry and repeated observations of white sturgeon at these sites.

Data Gaps -- There are moderate data gaps for determining the geographic boundaries of this important habitat component; river kilometres discussed here are approximate.  These areas defined as important habitat are fairly broad, and are based on existing information of white sturgeon habitat use.  Additional studies may increase the confidence in these boundaries and may permit greater precision in defining the geographic areas of interest. 

3.3 Lower Fraser River

In the lower Fraser River, white sturgeon occur from the Hell’s Gate canyon at km 210, downstream to the estuary and marine confluence near Vancouver, within major salmon spawning tributaries, Pitt and Harrison Lakes, and in the upper Pitt and Lillooet rivers, as well as in the Georgia Strait and other near and offshore marine waters along the Pacific Coast.  Individuals from the middle Fraser River population have also been recorded migrating downstream into the lower Fraser River.  In-river migration is moderately well known, and movements between holding, spawning and feeding areas can be extensive (greater than 100 km).  The extent of migration to estuary and marine waters is poorly understood, but is currently being studied.  However, individual sturgeon that were tagged in the lower Columbia River were captured nearly 100 km upstream in the lower Fraser River indicating that extensive estuarine and marine use and migration is probable. This section of the river has several different reaches, including the restricted Fraser Canyon from km 210 to 160, the gravel reach from km 160 to approximately km 90, the lower gradient tidal influenced km 83 to approximately km 10, and the estuary from approximately km 10 to 5 out from the mouth.  In addition, lower Fraser River sturgeon have access to the marine waters of Georgia Strait and the Pacific, to the large tidal Pitt Lake, to the very large Harrison Lake and to numerous larger salmon producing tributaries.

Current abundance and distribution in the lower Fraser River is likely limited by habitat availability, which has been historically affected by significant floodplain and estuary development and disturbance.  It is also likely limited by the availability of prey/food, and as such the abundance of migrating eulachon, salmon and other fishes, by impacts from First Nations and commercial salmon gillnet and beach seine fisheries, and by impacts from the recreational fisheries.  The lower Fraser River population is also subjected to significant industrial developments, discharges and in-river activities, especially in the section downstream of km 94.  There are also numerous municipal and agricultural point and non-point source discharges in this section.  This area of the province houses more than approximately 60% of the human population of British Columbia and has numerous port facilities within and immediately adjacent to the lower river.

The lower Fraser River white sturgeon population was also assessed during the provincial study in the early 1990s.  Since 2000, an extensive ongoing volunteer based mark-recapture program has been conducted throughout this section of the river through the Fraser River Sturgeon Conservation Society (FRSCS).  Numerous other sturgeon studies have been recently conducted by the FRSCS and others on the lower river sturgeon population including recent juvenile sturgeon habitat use studies (Glova et al. 2008, 2009).

3.3.1 Spawning and Incubation Habitat

Spawning areas have been confirmed for mainstem and side channel locations within the gravel reach (river km 94-160) and within the Fraser Canyon from Hope upstream of Yale (km 160- 187).  However, the precise spawning locations may change from year to year depending on channel and substrate configurations, and flow conditions.  It is likely that the Harrison and Pitt Lake and River systems also have spawning and incubation areas that have yet to be identified.  Additional Fraser River mainstem spawning and incubation sites may also be identified in the future.  Recent research data indicates that white sturgeon eggs do not drift far, so incubation and early juvenile habitats are assumed to coincide with spawning habitats.

Important Spawning and Incubation Habitats -- The higher gradient side channels and large tributary river fans from the confluence of the Sumas/Vedder River upstream to the Coquihalla River and within the Fraser Canyon upstream to Saddle Rock are confirmed spawning and incubation areas for lower Fraser River white sturgeon.  This habitat would be deemed “important” on an annual basis during June, July and August, based on known timing of spawning and incubation.  This period is sufficient to encompass known annual variability in the onset of spawning.  The degree of certainty in this important habitat determination is rated as moderate; despite observations of spawning at these sites long term site specific studies are lacking. The delineation of broad areas for important spawning habitats for the lower Fraser River population is due to the combination of a lack of long term studies, the potential for habitat conditions to change from year to year, and the likelihood that various areas may be required for recovery.  Additionally, these areas may not be adequate for recovery of any sub-populations that may be delineated in the future.  The mainstem Fraser areas are indicated in Figures B-10 and B-11 and described as:

• Fraser River canyon (km 160-187); and,
• Fraser River side channels and main channel (km 94-160).

Data Gaps -- There are data gaps for determining the detailed specific geographic boundaries of these important habitats due to ongoing changes in channel and substrate configurations, variable flows and the high cost of conducting research on a large turbid river.  As such, it is difficult to determine and maintain precise habitat boundaries for multiple years over such a large area, or to confirm similar habitats.  There are also significant uncertainties with respect to the quality of habitat that is required to maintain this functionality for spawning, incubation and early life stages for the recovery of this population.

3.3.2 Early Juvenile Habitat

0 - 21 days -- Important habitat for this life stage is assumed to include areas within and immediately adjacent to spawning and incubation areas and a short distance downstream as indicated in Figures B-10 and B-11 and described by the following:

• Fraser River canyon (km 160-187); and,
• Fraser River side channels and main channel (km 94-160). 

21 days to 2 years -- Habitat needs within this 2 year period may be considerably different than in the life stage immediately preceding it.  It is likely that from age 1 onward, this stage uses habitat types similar to those preferred by immature and adult sturgeon, however habitat use prior to age 1 is uncertain.  Recent initial studies on habitat use indicate that fish from 1-2 years old use similar habitat to older juveniles and adults.  While concentrations in specific habitats may occur during particular times of the year no distinct concentrations have been identified.

Important Early Juvenile Habitats -- The important habitat for the 0 - 21 days stage is the same habitat area noted as important for spawning and incubation.  This habitat would be deemed important on an annual basis during June, July and August, based on suspected timing of spawning and incubation.  This period is sufficient to encompass expected annual variability in onset of spawning.  Important habitat would extend downstream beyond the boundaries of spawning and incubation habitat, but the downstream limit cannot be described at this time.  The degree of certainty in this important habitat determination is rated as high, based on repeated observations of spawning at this site, although there is insufficient certainty to define the downstream limit of this habitat beyond that already defined for spawning and incubation.

The important habitat for the 0 to 21 days stage is identified in Figures B-10 and B-11 and includes the following areas, which are also identified as spawning areas:

• Fraser River Canyon (km 160-187); and,
• Fraser River side channels and main channel (km 94-160).

The important habitat for the 21 days to 2 years stage includes the following areas, which are also identified as high use areas for multiple life stages:

• Peg Leg Bar (km 112-115);
• Grassy Bar and Island 22 (km 103-109);
• Vedder River Confluence (km 88-99);
• Hatzic Bend (km 80-89);
• Matsqui Island Channels (km 74-77);
• Annacis Island (km 19-25); and,
• Canoe Pass/Deas Island (km 9-12).
• km 200-205;
• km 198-199; and,
• km 185-187.

The following more general areas are also likely used as they are high use for late juvenile and adults during the salmon spawning period:

• Fraser Canyon (km 160-185); and,
• Fraser mainstem & wetted side channels (km 89-160).

These areas are depicted in Figures B-11 through B-13.  This habitat would be deemed important year-round, based on knowledge of continuous occupation of these sites.  The degree of certainty in this important habitat determination is rated as high, based on repeated observations and captures at these sites.

Data Gaps -- There are moderate data gaps for determining the geographic boundaries of this important habitat; river kilometres discussed here are approximate.  These areas defined as important habitat are fairly broad, and are based on existing information of white sturgeon habitat use.  Additional studies may increase the confidence in these boundaries and may permit greater precision in defining the more specific areas of interest within the larger areas currently identified. 

3.3.3 Late Juvenile and Adult Habitat

The late juvenile and adult stage is defined as occurring from 2 years onward.  Diets of younger fish may be considerably different than those of large adult fish, but in general, all individuals in this class occupy the same habitats for the purposes of feeding, and presumably for overwintering.

Important Late Juvenile and Adult OverwinteringHabitats -- In the lower Fraser River, overwintering habitats are typically associated with fall feeding habitats.  They are often carcass deposition areas downstream of salmon spawning areas and are slower deep areas that require minimal energy expenditure to inhabit.  The deepest holes in the river are known to be used for overwintering.  Confirmed locations noted as important overwintering areas are indicated in Figure B-12 and include:

• Peg Leg Bar (km 112-115);
• Grassy Bar and Island 22 (km 103-109);
• Hatzic Bend (km 80-89); and
• Matsqui Island Channels (km 74-77).

These areas support very high densities of sturgeon from the middle of December through to the middle of March, but are typically used extensively by sturgeon year-round.  The degree of certainty in this important habitat determination is rated as moderate, based on repeated observations of high use areas for overwintering.  Other important overwintering areas likely exist throughout the lower Fraser River and its larger tributaries, but have not been confirmed and additional work would be required to support any recommendations as important habitat.

Important Spring Migration & Feeding Habitats -- In the lower Fraser River, the onset of sturgeon spring migrations to feeding habitats is strongly associated with spring spawning anadromous or resident fish or their migrations, and with their spawning and downstream carcass deposition areas.  Important fish prey species during this period include eulachon and smelt, and likely trout, cyprinids and catastomids.  It appears that late juvenile and non-spawning adult sturgeon stay associated with these habitats through the freshet to the onset of upstream salmon migration in July and August.  Important spring spawning eulachon feeding areas are indicated in Figure B-13 and are described as follows:

• Pitt River Confluence (km P1-P4);
• Barnston Island (km 41-48);
• Douglas Island (km 37-40); and,
• Annacis Island (km 20-24). 

These areas would be considered important for spring and summer feeding during the period from approximately April 1st – August 1st.  Additional upstream eulachon spawning and sturgeon feeding areas have also been identified, but less frequently, and traditional ecological knowledge has confirmed that eulachon regularly migrated over 100 km upstream.  Additional spring feeding areas likely exist throughout the lower Fraser River, but have not yet been identified or confirmed.  These would include any spring spawning habitats including the confluences of large and smaller tributaries.

Important Adult Staging Habitats -- There are numerous deep holes in this river section used for staging and fish are known to move frequently throughout the entire section.   Fish were observed to move from these locations to the spawning site at or prior to the spawning period (RL & L 2000a). Important habitat features for staging are likely somewhat redundant with confirmed important adult feeding and overwintering habitats, as staging fish commonly occupy these areas just prior to spawning.  However, there also appears to be participation of large mature fish in the spring migration and feeding.Based on known habitat use, several areas have been confirmed as important habitats for adult staging.  These areas are indicated in Figure B-12 and include:

• Peg Leg Bar (km 112-115); and,
• Grassy Bar and Island 22 (km 103-109).

Areas within the section km 115 – 135 are considered important habitats for staging; however, additional work is required to confirm this area.  Other potential Fraser River side channels and main channel sites likely exist in deep holes in the following areas as indicated in Figures B-10 and B-11:

• Fraser River canyon (km 160-187); and,
• Fraser mainstem and wetted side channels (km 94-160).

These habitats would be deemed important during pre-spawn staging.  This would likely include the period from approximately May 15th to September 1st.  The degree of certainty in this important habitat determination is rated as high for confirmed sites and moderate for potential sites, based on repeated captures of white sturgeon at these sites and past studies.

Important Fall/Summer Migration & Late Summer & Fall Feeding Habitats -- In the lower Fraser River, the onset of sturgeon migrations to late summer and fall feeding habitats is strongly associated with spawning anadromous salmon migrations, and with their spawning and downstream carcass deposition areas.  Some of the lower Fraser River salmon spawning and carcass depositional areas that are important for sturgeon feeding are indicated in Figures B-10, B-11 and B-12 and described as follows:

• Fraser Canyon (km 160- 185);
• Fraser mainstem and wetted side channels (km 89-160);
• Peg Leg Bar (km 112-115);
• Grassy Bar and Island 22 (km 103-109);
• Vedder River Confluence (km 88-99);
• Hatzic Bend (km 80-89);
• Lower Stave River and Stave River Confluence (km 62-70); and,
• Lower Harrison River (km H1-H19)
• km 200-205;
• km 198-199; and,
• km 185-187.

Numerous other sites exist throughout this section of the river depending on the timing and extent of the spawning salmon species.  For example, feeding becomes more widespread and voracious annually during chum salmon migration and spawning, and biannually on odd years during pink salmon migration and spawning.  Sturgeon feed across channels at all depths during these periods.  Other heavily used feeding sites include the confluences and lower reaches of all large and small salmon spawning tributaries.  The timing of this activity varies with the timing and extent of the salmon migrations.  It typically occurs from approximately July 15th to December 15th.   However, salmon runs in the lower Fraser River continue through the winter into the early spring. 

Data Gaps -- There are moderate data gaps for determining the geographic boundaries of this important habitat component; river kilometres discussed here are approximate.  These areas defined as important habitat are fairly broad, and are based on existing information of white sturgeon habitat use.  Further studies should increase the confidence in these boundaries and greater precision in defining more specific geographic locations. 

3.4 Potential Threats to Important Habitat

Activities that may impact important habitat for mid and lower Fraser River white sturgeon include river regulation, gravel or sand dredging, bank protection, dyke construction and bank armouring, linear developments, riparian, foreshore, floodplain alterations or developments, upstream land and water uses, and point and non-point source pollution discharges.  The exact concerns would vary depending on details of the activities, location and applied mitigation measures.  General threats to white sturgeon and their habitats are discussed in the Recovery Strategy.

3.5 Figures

The following graphics are at a smaller scale for practical presentation of strategic information.  Users or regulatory agencies should consult regional B.C. Ministry of Environment sturgeon biologists and/or the lower and middle Fraser River white sturgeon working groups to confirm accurate locations of important areas.

Figure B-1. Important habitat for middle Fraser River white sturgeon. A section of the middle Fraser River is depicted flowing in a southeastward direction. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction. An upstream section of river is circled in red in the vicinity of the Cottonwood confluence (roughly 674.5 to 670.5); this is one of only two designated spawning habitats for this population and is identified as important habitat for spawning, incubation and early juvenile (0 – 21 days) life stages. A meander is present south of the upper red polygon. Downstream, another stretch of river (roughly 642.5 to 646) is outlined in red in the vicinity of the Quesnel River confluence, important for all other life history stages from early juvenile to overwintering. The map is oriented in a “north is up” direction.

Figure B-1.  Important habitat for Middle Fraser River white sturgeon.  The upstream red outlined polygon is in the vicinity of the Cottonwood River confluence. This is one of only two designated spawning habitats for this population and is identified as important habitat for spawning, incubation and early juvenile (0 – 21 days) life stages.  The downstream red outlined polygon is in the vicinity of the Quesnel River confluence and is important for all other life history stages from early juvenile to overwintering.

Figure B-2. Important habitat for middle Fraser River white sturgeon. A section of the middle Fraser River is depicted flowing in a southward direction through Williams Lake. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction.  The lower portion of an upstream red outlined polygon is located between Hawks Creek and Williams Creek. This is one of only two designated spawning habitats for this population and is identified as important habitat for spawning, incubation and early juvenile (0-21 days) life stages. The remainder of this polygon and a downstream red outlined polygon are important for all other life history stages from early juvenile to overwintering. The upstream polygon runs from roughly 538 to 552 and the downstream polygon runs roughly from 519 to 525. The map is oriented in a “north is up” direction.

Figure B-2. Important habitat for Middle Fraser River white sturgeon. The lower portion of the upstream red outlined polygon is located between Hawks Creek and Williams Creek. This is one of only two designated spawning habitats for this population and is identified as important habitat for spawning, incubation and early juvenile (0-21 days) life stages.  The remainder of this polygon and the downstream red outlined polygon are important for all other life history stages from early juvenile to overwintering.

Figure B-3. Important habitat for middle Fraser River white sturgeon. A section of the middle Fraser River is depicted flowing in a southward direction roughly between Dog Creek Dome and Junction Sheep Range Provincial Park. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction. A meander is present at the northern end of this river section. Three red outlined polygons indicate important habitats for life history stages, including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river. The upstream polygon runs roughly from 484 to 495, the middle polygon from 473 to 482, and the downstream polygon from 467 to 470. The map is oriented in a “north is up” direction. 

Figure B-3. Important habitat for Middle Fraser River white sturgeon. The red outlined polygons are important for life history stages, including early juvenile and overwintering.  No spawning habitat has been confirmed in this section of the river.

Figure B-4. Important habitat for middle Fraser River white sturgeon. A section of the middle Fraser River is depicted flowing in a southeastward direction through the Churn Creek Protected Area. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction. Four red outlined polygons indicate important habitats for all life history stages, including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river. The map is oriented in a “north is up” direction. 

Figure B-4. Important habitat for Middle Fraser River white sturgeon. The red outlined polygons are important for all life history stages, including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river.

Figure B-5. Important habitat for middle Fraser River white sturgeon.  A section of the middle Fraser River is depicted flowing in a southward direction roughly between Lillooet and Edge Hills Provincial Park. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction. A meander is present at the southern end of this river section. Two red outlined polygons indicate important habitats for all life history stages including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river. The upstream polygon runs roughly from 357 to 358.5 and the downstream polygon from 349.5 to 350.5. The map is oriented in a “north is up” direction. 

Figure B-5. Important habitat for Middle Fraser River white sturgeon. The red outlined polygons are important for all life history stages including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river.

Figure B-6. Important habitat for middle Fraser River white sturgeon. A section of the middle Fraser River is depicted flowing in a southeastward direction through Lillooet. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction.  A meander is present at the northern end of this river section. Two red outlined polygons indicate important habitats for all life history stages including early juvenile and overwintering. Spawning habitat is suspected, but has not been confirmed in the lower section of the upper polygon. The upstream polygon runs roughly from 367 to 368.5 and the downstream polygon from 349.5 to 350.5. The map is oriented in a “north is up” direction. 

Figure B-6. Important habitat for Middle Fraser River white sturgeon. The red outlined polygons are important for all life history stages including early juvenile and overwintering. Spawning habitat is suspected, but has not been confirmed in the lower section of the upper polygon.

Figure B-7. Important habitat for middle Fraser River white sturgeon. A section of the middle Fraser River is depicted flowing in a southward direction through Lytton. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction. Three red outlined polygons indicate important habitats for all life history stages including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river. The map is oriented in a “north is up” direction. 

Figure B-7. Important habitat for Middle Fraser River white sturgeon. The red outlined polygons are important for all life history stages including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river.

Figure B-8. Important habitat for middle Fraser River white sturgeon. A section of the middle Fraser River is depicted flowing in a southward direction roughly through Spuzzum and Yale. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction.  A meander is present in the middle (near Saddle Rock) and southern end (near Yale) of this river section. Three red outlined polygons indicate important habitats for all life history stages including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river. The upstream polygon runs roughly from 199 to 205, the middle polygon from 197 to 199 and the downstream polygon from 184 to 187. The map is oriented in a “north is up” direction. 

Figure B-8. Important habitat for Middle Fraser River white sturgeon. The red outlined polygons are important for all life history stages including early juvenile and overwintering. No spawning habitat has been confirmed in this section of the river.

Figure B-9. Important habitats for lower Fraser River white sturgeon. A section of the lower Fraser River is depicted flowing in a southward direction through Yale. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction.  A meander is present in the northern and southern ends of this river section. A red outlined polygon indicates areas known of sturgeon spawning habitat, running roughly from 159 - 187. These habitats are also used extensively for summer to late fall feeding habitats. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas. The map is oriented in a “north is up” direction. 

Figure B-9. Important habitats for Lower Fraser River white sturgeon. The red outlined polygons identify areas known of sturgeon spawning habitat. These habitats are also used extensively for summer to late fall feeding habitats. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas.

Figure B-10. Important habitats for lower Fraser River white sturgeon. A section of the lower Fraser River is depicted flowing in a southwestward direction through Hope, Harrison Hot Springs, Agassiz, and Chilliwack. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction.  A red outlined polygon indicates areas known to contain sturgeon spawning habitats, with the exception of the Harrison River. The polygon runs from roughly 93 to 156 and H1 to H18. These habitats are also used extensively for summer to late fall feeding habitats. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas. The map is oriented in a “north is up” direction. 

Figure B-10. Important habitats for Lower Fraser River white sturgeon. The red outlined polygons identify areas known to contain sturgeon spawning habitats, with the exception of the Harrison River. These habitats are also used extensively for summer to late fall feeding habitats. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas.

Figure B-11. Important habitats for lower Fraser River white sturgeon. A section of the lower Fraser River is depicted flowing in a westward direction through Agassiz, Chilliwack, Abbotsford and Mission. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction.  Five red outlined polygons indicate areas known to be used extensively for overwintering habitats, and for spring and summer to late fall feeding habitats. Moving upstream to downstream, the first polygon runs roughly from 116-111, the second from 102 – 109.5, the third from 89.5 – 99, the fourth from 79 – 89.5, and the fifth from 73.5 – 77. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas. The map is oriented in a “north is up” direction. 

Figure B-11. Important habitats for Lower Fraser River white sturgeon. The red outlined polygons identify areas known to be used extensively for overwintering habitats, and for spring and summer to late fall feeding habitats. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas.

Figure B-12. Important habitats for lower Fraser River white sturgeon.  A section of the lower Fraser River is depicted flowing in a westward direction through Maple Ridge, Pitt Meadows, Port-Coquitlam, Coquitlam, New Westminster, Surrey, Richmond, and Delta. Points along the river labeled with numbers represent sequentially numbered kilometers of river, increasing in an upstream direction.  Four red outlined polygons indicate areas known to be used extensively for spring and summer to late fall feeding habitats. Moving from upstream to downstream, the first polygon runs roughly from 36 to 48, the second polygon from P1 to P4.5, the third polygon from 17.5 to 25.5, and the fourth polygon from 7.5 to 11.5. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas. The map is oriented in a “north is up” direction. 

Figure B-12. Important habitats for Lower Fraser River white sturgeon. The red outlined polygons identify areas known to be used extensively for spring and summer to late fall feeding habitats. The purple shaded areas are additional confirmed important juvenile and adult sturgeon holding and feeding areas.

References

Glova, G., T. Nelson, K. English, and T. Mochizuki. 2009. A further report on juvenile white sturgeon habitat use in the lower Fraser River, 2008-2009.  Prepared by LGL Limited for the Fraser River Sturgeon Conservation Society, Vancouver, B.C.

Glova, G., T. Nelson, K. English, and T. Mochizuki. 2008. A preliminary report on juvenile white sturgeon habitat use in the lower Fraser River, 2007-2008.  Prepared by LGL Limited for the Fraser River Sturgeon Conservation Society, Vancouver, B.C.

¹⁷ Note: information in the Recovery of Lower and Mid Fraser Populations appendix is current to 2009.