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Recovery Strategy for the Salish Sucker (Catostomus sp.) in Canada (proposed)

4. Recovery

4.1 Recovery feasibility

Feasibility criteriaFootnote 4

  1. Are individuals capable of reproduction currently available to improve the population growth or population abundance?

    Yes. Breeding adults have been captured recently from all populations except that of the Little Campbell River, which is believed to have been extirpated.

  2. Is sufficient habitat available to support the species or could it be made available through habitat management or restoration?

    Yes. Sufficient physical habitat exists to support target population sizes, but a large fraction of it (up to 40%) is seriously degraded by hypoxia and/or low water levels in late summer.

  3. Can significant threats to the species or its habitats be avoided or mitigated through recovery actions?

    Yes. The largest threats, hypoxia and habitat loss can be avoided or mitigated.

  4. Do the necessary recovery techniques exist and are they demonstrated to be effective?

    Yes. Monitoring of experimental habitat restoration projects has demonstrated that habitat creation and restoration are effective means of increasing population size and stability. Invasive weed control, riparian restoration, beaver management, and flow diversion have all been used successfully to reduce hypoxia in Salish Sucker habitat.

Feasibility assessment

Recovery of Salish Sucker populations to levels ensuring long-term survival is both technically and biologically feasible. Given the restricted distribution of the species and the continued pressure on its habitats from a rapidly growing human population in the Fraser Valley it is likely that the species will remain at risk over the foreseeable future.

4.2 Recovery goal, objectives and corresponding approaches

4.2.1 Recovery goal

Ensure the long-term viability of Salish Sucker populations throughout their natural distribution in Canada.


4.2.2 Recovery objectives

  1. Prevent extirpation of Salish Suckers in each of the 10 watersheds with extant populations by preventing net loss of reproductive potential.
  2. Reach or exceed each of the following targets by 2020:
    1. occupation of all instream critical habitats,
    2. watershed-specific abundance targets for mature individuals,
    3. one or more source habitats with high density in each watershed.
  3. Reintroduce the Salish Sucker to Little Campbell River, if feasible.


The objectives 2 and 3 are discussed in detail below.

Occupation of instream critical habitats
Rationale:

A high proportion of critical habitat is not currently occupied (Table 9), primarily due to severe hypoxia. Achieving interim population recovery targets requires that all critical habitat be occupied (see objective 2 below). In most cases, unoccupied areas could become habitable by improving water quality via increased water flow and/or reduced nutrient loading. Relatively simple measures including localized beaver control, fish-sensitive drainage maintenance practices or, in the case of Agassiz Slough, restoration of through-flow are likely to produce dramatic improvements quickly.

Target:

Occupation of critical habitat is defined as, Salish Sucker confirmed present in a reach (n>10 traps per reach; see Pearson & Healey 2003). The amount of critical habitat currently occupied and the amounts identified to support target abundances are presented in Table 9. The difference between the two columns represents the amount of habitat that requires some form of restoration.

Table 9. Occupied and total critical habitat for the Salish Sucker.
WatershedEstimated length (km) of Currently Occupied Critical Habitat (year surveyed)Total Critical Habitat Identified to Reach Recovery Targets (km)
Agassiz Slough<1 (2005)4.3
Atchelitz/Chilliwack/Semmihault<16 (2004)32.4
Bertrand Creek>10 (2009)15.0
Fishtrap CreekUnknownFootnote a (1999)6.5
Hope Slough/Elk CreekUnknownFootnote a (2006)23.6
Miami Creek<1.8 (2002)7.8
Mountain Slough>7.5 (2008)9.7
Pepin Brook>7.5 (2004)11.6
Salmon River>10 (2008)20.2
Salwein Creek/Hopedale Slough<2.5 (2004)10.8

Footnotes

Footnote A

Too few individuals were captured to assess occupancy.

Return to footnote a


Watershed-specific abundance targets for mature individuals
Rationale:

Populations of Salish Sucker in the 10 watersheds where they occur are essentially independent of one another, with low probability of natural exchange of individuals between watersheds. Natural exchange is limited by large distances of unsuitable habitat that separate populations. Natural recolonization of habitat from which a population has been extirpated (rescue effect) is therefore highly unlikely, especially if extirpation is due to progressive habitat or water quality degradation, rather than stochastic events. Each watershed, consequently, warrants a separate recovery target. Ideally, these targets would be based on robust population viability analyses, but the necessary demographic data is lacking for the Salish Sucker. Recommendations based on extensive literature reviews indicate that a minimum viable population size (MVP) of 7 000 breeding adults (median value; range 2 000-10 000) will ensure long term persistence in the majority of vertebrates (Reed et al. 2003; Thomas 1990).

To assess Salish Sucker abundance Pearson (2004a) estimated density from catch-per-unit-effort in 84 reaches in four watersheds using an equation calibrated with capture-recapture data. Salish Suckers were present in 34 of these reaches, but density estimates exceeded 0.05 adult/m² in only seven of them. The maximum achievable population in each watershed was estimated by assuming this density occurs in all deep pool habitats within critical habitat reaches. The data suggest that if all deep pool areas in all critical habitat reaches supported this ‘medium density’ (Pearson 2004a), all populations would remain at or below the estimated median minimum viable population (MVP) for vertebrates (7000). This suggests that the maximum achievable population sizes are close to the minimum viable population sizes in these watersheds and that all suitable habitats should be designated critical. Enhancement of critical habitat to increase carrying capacity and construction/restoration of additional habitat is advisable in all watersheds to increase safety margins.

Target:

Watershed-specific abundance targets are presented in Table 10.

One or more source habitats with high density in each watershed
Rationale:

Available distribution data suggest that Salish Sucker populations within watersheds function as source-sink and/or metapopulation systems (Pearson 2004a). In metapopulation systems, subpopulations within watersheds are largely isolated from one another, connected only by occasional migrants (Forman 1995). Population growth may be positive in core (source) habitats of these subpopulations, but negative in surrounding (sink) habitats, even though a substantial portion of the population may reside in sink areas (Pullman 1988). Population persistence in such systems is dependent on the existence of one or more source habitats where population growth is positive and densities are high.

Target:

Source habitat for the Salish Sucker is defined based on a minimum catch-per-unit-effort of three adults/trap. Pearson (2004a) found only three examples among 84 reaches in 4 watersheds. In two more recently restored habitats in Pepin Brook with adequate dissolved oxygen levels, however, this threshold has been achieved within three years (Pearson, unpubl. data), implying that the goal is achievable.

 

Table 10. Area of deep pools and population targets for the Salish Sucker.
WatershedArea of Deep Pool in Critical Habitat Reaches (m2)Population TargetFootnote a
(excludes young of year)
Agassiz Slough39 2002 000
Atchelitz/Chilliwack/Semmihault140 0007 000
Bertrand Creek140 2007 000
Fishtrap Creek94 6004 700
Hope Slough/Elk Creek159 7008 000
Miami Creek30 0001 500
Mountain Slough88 7004 400
Pepin Brook24 000Footnote b1 200
Salmon River165 0008 200
Salwein Creek/Hopedale Slough53 900Footnote b2 700

Footnotes

Footnote A

See Rationale for methods used for determining targets. All numbers rounded to nearest hundred.

Return to footnote a

Footnote B

Does not include several thousand square metres of habitat constructed since 2005.

Return to footnote b


Reintroduce the Salish Sucker to the Little Campbell River, if feasible
Rationale:

Re-establishment of extirpated populations is necessary to fully achieve the strategy’s overall goal: “To ensure long-term viability of Salish Sucker populations throughout their natural distribution in Canada.” This will only be feasible if sufficient habitat is available and threats (e.g., habitat quality and introduced alien predators) are sufficiently mitigated. The goal to have Salish Suckers occupy the full natural range is reasonable, given the species’ restricted distribution in Canada.


4.2.3 Broad strategies to support the recovery objectives

Nine broad strategies have been identified in support of the recovery objectives:

  1. Reduce incidence of severe hypoxia in instream critical habitats.
  2. Protect existing habitat, restore lost or degraded habitat and create new habitat.
  3. Increase the integrity and function of all riparian habitats.
  4. Encourage stewardship among private landowners, local government and agencies, and the general public.
  5. Reduce fragmentation of instream and riparian habitats.
  6. Reduce toxic contamination of instream habitat.
  7. Reduce sediment entry to instream habitats.
  8. Assess impacts of predator introduction and prevent new introductions.
  9. Assess feasibility of reintroducing the Salish Sucker into the Little Campbell River if extirpation from watershed is confirmed.

In Table 11 these strategies are described in greater detail, prioritized and related to the recovery goal and objectives.


4.2.4 Evaluation

Ideally, monitoring and evaluation of a subset of populations should occur each year and the status of each population and watershed evaluated at least every five years. Performance measures for each objective and broad strategy are listed in Table 12. Details and priorities of strategy implementation will be provided in one or more action plans.


4.2.5 Effects on other species

Most recovery efforts will benefit co-occurring native species including Steelhead (Oncorhynchus mykiss), Cutthroat Trout (Oncorhynchus clarkii clarkii) and Coho Salmon (Oncorhynchus kisutch). In particular, Coho Salmon are likely to benefit because juveniles often share habitat with Salish Suckers (Pearson 2004a).

Many Species at Risk Act (SARA)-listed species are known to occur in streams and riparian areas supporting Salish Suckers. The Nooksack Dace (Rhinichthys cataractae sp., Pearson 2004a), Oregon Spotted Frog (Rana pretiosa, Haycock 2000), and Western Painted Turtle (Chrysemys picta) occupy aquatic areas in some Salish Sucker habitat. Nooksack Dace occur primarily in riffles and are seldom found in the same reaches as the Salish Sucker (Pearson 2004a). They are unlikely to be harmed by any of the activities described in this strategy and will benefit from many of them. American Beaver (Castor canadensis) control measures may be necessary in Pepin Brook to counteract inundation of riffles, the primary habitat of Nooksack Dace. This work would likely benefit the Salish Sucker preserving spawning riffles and by reducing hypoxia (currently a threat in the affected reaches) through increased water movement, although some loss of deep pool habitat will also occur. An action plan will consider habitat management jointly for the Salish Sucker and Nooksack Dace in the watersheds in which they co-occur.

Oregon Spotted Frogs occur in the same reaches as the Salish Sucker in Mountain Slough, near Agassiz and in Bertrand Creek, near Aldergrove. The frogs are likely to benefit from recovery activities described in this strategy, particularly those that increase oxygen levels in the water (Haycock pers. comm. 2005). Development of best management practices for instream works in habitats where Oregon Spotted Frogs and Salish Suckers coexist will be completed in cooperation with the Oregon Spotted Frog Recovery Team.

Western Painted Turtles occur in the same reaches as Salish Suckers in Salwein Creek, near Chilliwack. The turtles are likely to benefit from the creation and complexing of deep pool habitats for the Salish Sucker. A habitat enhancement project to benefit both species was initiated in Salwein Creek by members of both Recovery Teams in September 2009.

Many other SARA-listed species are known from riparian areas of Salish Sucker habitat, including the Pacific Water Shrew (Sorex bendirii), Red-legged Frog (Rana aurora), Western Toad (Bufo boreas), Mountain Beaver (Aplodontia rufa), Oregon Forestsnail (Allogona townsendiana), Vancouver Island Beggarticks (Bidens amplissima), and Great Blue Heron (Ardea herodias fannini). None are expected to be harmed by activities proposed in this recovery strategy, and most are expected to benefit from the protection and restoration of native riparian vegetation.

 

Table 11. Broad strategies, research activities and management activities to support the recovery objectives for the Salish Sucker.
Broad StrategyObjectivesThreats AddressedPrioritySpecific ActivitiesOutcomes or Deliverables
1) Reduce incidence of severe hypoxia in instream critical habitats.1, 2HypoxiaHigh

Assess extent, severity, causes and impacts of hypoxia in all watersheds.

Work with stakeholders to eliminate sources of nutrient loading and to increase extent of riparian buffers adjacent to Salish Sucker streams.

Work with municipalities to develop drainage maintenance and beaver management protocols that increase flow without degrading habitat.

Develop and distribute public education materials on the impacts of hypoxia on fish and wildlife to landowners.

Late summer hypoxia maps completed for all watersheds.

Increased dissolved oxygen levels in critical habitats susceptible to hypoxia.

2) Protect existing habitat, restore lost or degraded habitat and create new habitat.1, 2

Physical destruction of habitat

Habitat fragmentation

High

Assess benefits of habitat creation and enhancement to Salish Sucker populations.

Identify high priority sites for protection, restoration or habitat creation.

Work with stewardship groups and landowners to identify and implement habitat creation and restoration projects.

Develop best management practices and work plans for critical habitat reaches that require drainage maintenance or beaver management.

Develop guidelines for joint management where Salish Suckers and other listed species co-occur.

Develop and distribute materials to landowners regarding the importance of habitat.

There are a variety of possible mechanisms to protect critical habitat and other habitats, only some of which are presented here.

Habitat management plan developed for each occupied watershed.

Protection of critical habitat through stewardship agreements, conservation covenants, acquisition or other mechanisms.

Habitat creation/enhancement projects identified and implemented.

Advice on Salish Sucker habitat requirements for local stewardship groups, agencies and consultants involved in habitat work.

Educational materials developed and included in landowner contact programs and other public education applications.

3) Increase the integrity and function of all riparian habitats.1, 2

Sediment deposition

Physical destruction of habitat

Toxicity

Hypoxia

High

Conduct riparian assessments in all critical habitat reaches and make recommendations for reserve zones and other mitigative measures.

Identify, prioritize and develop riparian planting projects in cooperation with landowners, stewardship groups and government agencies.

Develop and distribute public education materials to landowners on riparian reserve strips.

Riparian assessments completed as the basis for establishing defensible reserve zones to protect instream critical habitat.

Riparian planting projects completed in high priority areas.

Educational materials developed and included in landowner contact programs and other public education applications.

4) Encourage stewardship among private landowners, local government and agencies, and the general public.1, 2AllMed

Give presentations and field tours on Salish Suckers and watershed ecology to local stewardship groups, school groups and others.

Advise stewardship groups, agencies and consultants involved in habitat work on Salish Sucker habitat requirements.

Increased awareness of Salish Suckers and local stream ecology among public.

Salish Sucker habitat features incorporated into instream works undertaken for other purposes.

5) Reduce fragmentation of instream and riparian habitats.1, 2Habitat fragmentationMed

Assess the ability of different life stages to cross barriers such as beaver dams and perched or undersized culverts.

Identify permanent/seasonal barriers and prioritize for mitigation.

Identify, prioritize and develop riparian planting projects in cooperation with landowners, stewardship groups and government agencies.

Use of strategically located restoration projects to eliminate barriers and provide ‘stepping stones’ for dispersal to occupied habitats.

Prioritize restoration projects available to local stewardship groups and agency staff involved in habitat work.

6) Reduce toxic contamination of instream habitat.1, 2ToxicityMed

Estimate extent and severity of toxic contamination of creeks.

Work with municipalities to identify, prioritize and develop projects to improve stormwater quality.

Increase width and continuity of riparian reserves (see strategy 3) on agricultural lands.

Develop and distribute public education materials on pesticide/herbicide impacts on fish and wildlife.

Stormwater treatment projects completed at high priority sites.

Riparian planting projects completed in high priority areas.

Educational materials developed and included in landowner contact programs and other public education applications.

7) Reduce sediment entry to instream habitats.1, 2Sediment depositionMed

Estimate levels of sediment in riffles that are harmful to Salish Sucker spawning and incubation.

Map, assess and prioritize mitigation for riffle sedimentation in all watersheds.

Work with landowners, local government and stewardship groups to prevent, mitigate and restore sediment degradation of riffles.

Develop and distribute public education materials on sediment impacts on fish and wildlife.

Recommendations for maximum levels of sedimentation in riffles for Salish Sucker habitat.

Mitigation completed at high priority sites.

Educational materials developed and included in landowner contact programs and other public education applications.

8) Reduce impacts of introduced predators.1, 2Increased predationLow

Document distribution and density of introduced predators in each watershed.

Evaluate susceptibility of different life stages to introduced predators.

Develop and distribute public education materials on impacts of introduced predators on native species.

Maps of introduced predator distributions in each watershed.

Educational materials developed and included in landowner contact programs and other public education applications.

9) Assess feasibility of reintroducing the Salish Sucker into the Little Campbell River.3Multiple threats of unknown severityLow

Confirm extirpation and analyze causes and severity of current threats. Evaluate mitigation options.

If extirpation is confirmed, estimate number of individuals necessary to establish a population.

If extirpation is confirmed, evaluate options for obtaining fish or eggs for transplant.

Extirpation or presence of Salish Sucker in Little Campbell River confirmed

Completed feasibility study if extirpation is confirmed.

Contingent on feasibility study, the reestablishment of a viable Salish Sucker population in the Little Campbell River by 2020.

 

Table 12 (Objectives). Performance measures for evaluating the achievement of objectives and success of strategies.
ObjectivesProcess Performance MeasureBiological Performance Measure
1) Prevent extirpation of the Salish Sucker in each of the 10 watersheds with extant populations by preventing net loss of reproductive potential.Abundance surveys completed in all watersheds.Stable or increasing populations in all watersheds
2) a. Occupation of all instream critical habitats by 2020.Critical habitat identified and occupancy evaluated in all watersheds.Proportion of instream critical habitat occupied.
2) b. Reach or exceed watershed-specific abundance targets for mature individuals
by 2020.
Abundance surveys completed in all watersheds.

Estimated population size relative to target populationFootnote a.

Number of watersheds that yield an average catch-per-unit-effort of 1.8 or more adults per trap in critical habitat reaches.

2) c. One or more source habitats with high density in each watershed. by 2020.Abundance surveys completed in all watersheds.Number of watersheds with at least one reach where catch-per-unit-effort exceeds 3 adult Salish Suckers per trap.
3) Reintroduce the Salish Sucker to the Little Campbell River, if feasible.Feasibility study complete.Feasibility findings.

 

Table 12 continued (Strategies). Performance measures for evaluating the achievement of objectives and success of strategies.
StrategiesProcess Performance MeasureBiological Performance Measure
Reduce incidence of severe hypoxia in instream critical habitats.

Maps of critical habitat sites requiring increased water movement.

Area of critical habitat benefiting from management efforts to increase water movement.

Length and area of riparian habitat restored in each watershed.

Area and proportion of critical habitat with dissolved oxygen concentrations above 4 mg/L.

Proportion of critical habitat with measurable flow.

Estimated change in nutrient loading to ground and surface water in watersheds.

Establishment or significant growth of Salish Sucker populations in critical habitat reaches with increased water movement.

Protect existing habitat, restore lost or degraded habitat and create new habitat.

Prioritized list of habitat requiring protection or restoration.

Number of successful restoration/protection projects completed.

Length of critical habitat restored and/or protected.

Proportion of critical habitat restored and/or protected.

Establishment or significant growth of Salish Sucker populations in critical habitat reaches containing protected, created or enhanced habitat.

Increase the integrity and function of all riparian habitats.

Number of riparian assessments completed.

Length and area of riparian habitat restored or enhanced in each watershed.

Length and proportion of critical habitat with greater than 5, 10, and 30 m of riparian reserve.

Establishment or significant growth of Salish Sucker populations in critical habitat reaches with restored riparian reserve strips.

Encourage stewardship among private landowners, local government and agencies, and the general public.

Number of non-government organizations involved in recovery activities.

Number of projects completed or agreements signed on private lands.

Number of landowners and others contacted or involved in programs and consultations.

Length of critical habitat protected or restored on private land or with public involvement.

Establishment or significant growth of Salish Sucker populations in critical habitat reaches on stewarded lands.

Reduce fragmentation of instream and riparian habitats.

Maps of permanent and seasonal barriers to movement in each watershed.

Number of barrier remediation projects undertaken.

Quantity of habitat reconnected by removal of barriers.

Establishment or significant growth of Salish Sucker populations in critical habitat reaches where habitat fragmentation has been addressed.

Reduce toxic contamination of instream habitat.

Identified sources of toxic contamination in each watershed.

Mitigation of toxic contamination.

Area and proportion of critical habitat affected by toxic contamination.

Establishment or significant growth of Salish Sucker populations in critical habitat reaches affected by toxic contamination.

Reduce sediment entry to instream habitats.

Identification of major sources of sediment entry to each watershed.

Development and implementation of sediment mitigation plans.

Area and proportion of critical habitat affected by sediment deposition.

Establishment or significant growth of Salish Sucker populations in critical habitat reaches where sediment deposition has been addressed.

Reduce impacts of introduced predators.Maps of critical habitat occupied by introduced predators.

Proportion of critical habitat containing introduced predators.

Correlation of establishment or growth of Salish Sucker population with introduced predator absence.

Assess feasibility of reintroducing the Salish Sucker into the Little Campbell River.Feasibility study complete.Successful reintroduction, if judged feasible.

Footnotes

Footnote A

Direct estimation of density using capture-recapture methods is far too time consuming for use in monitoring ten populations spread over more than 100 km of channel.  Consequently, catch-per-unit-effort is recommended as the performance measure. An average of 1.8 adults/trap (n>10 traps per reach), corresponds to a density of 0.05 adult/m2 according to equations developed by Pearson (2004a), and is considered an appropriate target for proposed critical habitat at the watershed scale.

Return to footnote a

4.3 Approaches to recovery

An active adaptive management approach (Walters & Holling 1990) should be used in planning and implementing recovery. Whenever possible, management actions should be conducted as controlled experiments designed to inform ongoing strategy and action planning. Recovery planning and implementation should occur at the scale of individual watersheds because the populations are isolated from one another and face different suites of threats in each watershed.

4.4 Actions already completed or underway

Experimental habitat restoration projects

Experimental habitat restoration work targeting the Salish Sucker was initiated by University of British Columbia researchers in cooperation with local stewardship groups and landowners in 1999. Population size and habitat conditions have been monitored repeatedly at two sites in the Pepin Brook watershed (Pearson unpubl) Using this information, additional projects have been constructed in Salwein Creek and Hopedale Slough, Mountain Slough, Bertrand Creek, and the Salmon River by Dr. Mike Pearson, working in cooperation with Fisheries and Oceans Canada (DFO), the Township of Langley and the District of Kent. Monitoring should continue on these projects.

Integrated channel maintenance pilot projects

Agricultural drainage maintenance and fish habitat protection objectives have often been in conflict in the Fraser Valley. In 2003, the City of Chilliwack initiated a pilot project integrating drainage maintenance and fish habitat restoration in Salwein Creek, a Salish Sucker watershed. Hand maintenance protocols and shade from riparian zone plantings reduce the need for machine cleaning of waterways for drainage. When machine work is necessary to maintain drainage, additional habitat is constructed as part of the work. In 2004, DFO and the recovery implementation group helped expand the project to another Salish Sucker stream, Atchelitz Creek. A similar program is also underway with the District of Kent in portions of Mountain Slough and the Miami River. Expansion of this program to other watersheds and jurisdictions would be beneficial to the Salish Sucker and other native species.

Landowner contact and public education programs

Between 2000 and 2006, the Langley Environmental Partners Society and the Fraser Valley Regional Watersheds Coalition ran landowner contact programs in cooperation with members of the Recovery Team in all watersheds currently inhabited by the Salish Sucker. Public information meetings were also held in each watershed. Colour display posters on Salish Suckers have also been given to stewardship groups in Chilliwack, Langley and Agassiz for use during public events. Since 2000, Dr. Mike Pearson has provided lectures and habitat enhancement site tours featuring the Salish Sucker and recovery efforts to local schools, universities and stewardship groups each year through the Langley Environmental Partners Society.

Native plants program

Since 2000, native plants and livestock fencing have been provided and installed for landowners of riparian habitats along reaches containing the Salish Sucker in Agassiz Slough, Mountain Slough, Miami River, Salmon River, Bertrand Creek, Pepin Brook, the Little Chilliwack River, Elk Creek and Hope Slough. Much of this work has been done by community volunteers organized by three local stewardship groups (Langley Environmental Partners Society, Fraser Valley Regional Watersheds Coalition and Fraser Harrison Smart Growth) working in cooperation with Dr. Mike Pearson. Through various mechanisms, local governments such as the District of Kent and the Township of Langley have provided support and/or partnership for such projects.

4.5 Statement of when action plans will be completed

Within five years of posting the final Salish Sucker recovery strategy on the SARA Public Registry, one or more action plans will be prepared for the Nooksack Dace and Salish Sucker.

Footnotes

Footnote 4

Draft Policy on the Feasibility of Recovery, Species at Risk Act Policy. January 2005.

Return to footnote 4