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Recovery Strategy for the Western Silvery Minnow (Hypognathus argyritis) in Canada [Proposed]

5. Species Recovery

In addition to describing the species and threats to its survival or recovery, species recovery planning must consider:

  1. the biological and technical feasibility of recovery;
  2. an appropriate long term goal for the species recovery;
  3. recovery objectives for the species;
  4. strategies to address identified threats and to guide appropriate research, and management activities needed to meet the identified recovery objectives;
  5. identification of critical habitat or studies to identify such;
  6. potential effects on non-target species;
  7. actions already completed or currently underway;
  8. evaluation and performance of the recovery strategy; and
  9. the development of action plans.

A recovery strategy for the western silvery minnow described in these terms is provided below:

5.1 Recovery Feasibility

The following criteria and analyses were used to evaluate the biological and technical feasibility of recovery for the carmine shiner.

Reproductive Potential:  There is currently no impediment to the reproductive potential of the western silvery minnow populations in Canada. Viable populations exist within the lower Milk River where the species has been documented since 1961. Despite its apparently limited distribution there is no evidence that the distribution and/or abundance of the western silvery minnow is declining or has declined in recent years. One important consideration for the species persistence in Canada is its continuous distribution south of the international border to the Fresno Reservoir. Currently, there are no barriers upstream of the reservoir to prevent fish movement across the border and interchange between Alberta and Montana populations may be an important consideration in recovery planning. Upstream migration could have a rescue effect on Canadian populations.  Whereas, if downstream migration occurs, fish found in Canada might be exposed to threats in Montana, which currently does not protect the western silvery minnow or recognize it as a species at risk.

Habitat Availability:  The occurrence of viable populations documented over a number of years from the lower Milk River suggests that there is adequate habitat to support all life stages for the species at least in these locations.  Habitat availability is currently not limiting for maintenance of the species.

Threat Mitigation:  The potential for mitigating threats identified for the western silvery minnow (Section 3, Table 2) ranges from low to moderate, except for livestock access and scientific sampling, for which the mitigation potential is high.  At present, the latter are not believed to be influencing the species’ survival; the future impacts of climate change remain speculative. While future species introductions may have the potential to disrupt Alberta’s western silvery minnow populations, these impacts may be avoided by applying appropriate regulatory controls and management actions to prevent inadvertent introductions. The potential impact from most of the habitat related threats may also be reduced, or eliminated, if appropriate regulatory reviews and management actions are exercised, and best management practices are applied to existing or proposed projects. There are viable populations within the lower Milk River in Canada and downstream in the United States.  Conservation and threat mitigation efforts targeted at these populations should be able to secure and maintain their continued viability.  Threat mitigation may be complicated in some instances by the fact that Montana controls the flows diverted through the St. Mary Canal, subject to the provisions of the 1909 Boundary Waters Treaty and administration by the IJC.  Changes in flow conditions could influence potential recovery options, and recovery options should influence future recommended changes in flow regimes.  Continued international cooperation is crucial on trans-boundary issues.  Overall, the identified threats are not likely to impede the survival or recovery of the species. However, any improvement in our knowledge base for the species would improve our understanding of the potential impact of threats to it, and of the efficacy of any proposed mitigation measures.

Technical Capabilities:  The techniques likely to be contemplated for the conservation of the western silvery minnow populations are well founded in current science and management practices.  Given the relative abundance of the species within its limited distribution, the focus of recovery efforts should be on the mitigation of habitat impacts and the exclusion of unwanted species. The technical knowledge on how to deal with potential habitat impacts is well documented and applied globally. The avoidance of species introductions is best afforded through public education and management programs, both of which are entirely within the competency of the responsible jurisdictions. No impediments to the recovery of the western silvery minnow have been identified by any of the responsible agencies.

Biological and Technical Feasibility:  Given the above analysis, recovery of the western silvery minnow is deemed to be biologically and technically feasible.

5.2 Recovery Goal

No evidence to date suggests that the Milk River population of western silvery minnow has suffered a serious decline or that the range has been reduced significantly since it was first identified in the Milk River.  The population appears to persist naturally in this single Canadian location.  Given its limited distribution, the species may always be at some level of risk.  The focus of recovery planning should be to ensure a self-sustaining population by reducing or eliminating existing threats.  Given that population numbers and habitat do not appear to require recovery or restoration, a conservation approach based on protecting and maintaining existing populations and their habitats is recommended.  As such, the recovery goal for the western silvery minnow is:

“To protect and maintain a self-sustaining population of western silvery minnow within its current range within the Milk River in Canada.”

5.3 Recovery Objectives

A number of recovery objectives are proposed to meet the recovery goal and address any threats to the survival of the species. The objectives take into consideration the uncertainty associated with our knowledge of the species’ biology, life history, abundance, and habitat requirements as well as the impact of identified threats to its survival in the Milk River.  The recovery objectives are to:

  1. Quantify and maintain current population levels of western silvery minnow in the Milk River (within the population’s range of natural variation),
  2. Identify and protect critical habitat of the western silvery minnow; and to
  3. Identify potential threats to the western silvery minnow from human activities and ecological processes and develop plans to avoid, eliminate, or mitigate these threats.

5.4 Recovery Approaches and Strategies

Strategies proposed to address the identified threats, and to guide appropriate research and management activities to meet the recovery goal and objectives, are discussed under the broader approaches of:

  1. Research,
  2. Monitoring,
  3. Management and regulatory actions, and
  4. Education and outreach.

Each strategy has been designed to assess, mitigate or eliminate specific threats to the species; to address information deficiencies that might otherwise inhibit species recovery; or to contribute to the species recovery in general.  These strategies are summarized by approach in Table 3, which lists them in order of priority and relates them to specific recovery objectives.

5.4.1 Research

Sound scientific knowledge must form the basis of any recovery efforts for the western silvery minnow. Currently, many of the conclusions drawn for western silvery minnow in the Milk River are speculative and rely on very limited and often inferred information. Information gaps regarding basic life history, biology, habitat requirements, population structure and abundance, and threats exist and need to be addressed to refine the recovery strategy and ensure that the species is adequately protected in Canada.  To address the need for scientific research the following strategies are recommended:

  • Clarify life history requirements: Conduct scientific studies to understand the life history, ecology, population dynamics and population structure of the western silvery minnow.
  • Clarify habitat requirements: Conduct scientific studies to determine biophysical attributes of habitat required seasonally by each life stage of the western silvery minnow with a specific focus on identifying critical habitat for the species.
  • Develop population models: Conduct scientific studies to establish reliable population models including population viability estimates, as well as appropriate surrogate measures relying on relative abundance, presence/absence and population structure data.
  • Identify limiting factors:  Conduct scientific studies to better understand the potential threats associated with human activities including water regulation (e.g. dam, canal operations), land use practices, species introductions, and climate change.
Table 3. Recovery objectives, the strategies to address them, and their anticipated effects.
StrategyPriority*Anticipated Effect
Objective 1: To quantify and maintain current population levels of western silvery minnow in the Milk River (within the population’s range of natural variation), as measured by relative abundance determined from a standardized survey program.
R3. Develop population modelsUrgentProvide trend through time data. Improve knowledge of natural variability and population viability.  Improve ability to identify anthropogenic impacts.
M1. Population monitoringUrgent
Objective 2: To increase knowledge of the life history, basic biology and habitat requirements of the western silvery minnow, with a view towards identifying and protecting critical habitat.
R1. Clarify life historyNecessaryEnable identification of important or critical habitat. Better knowledge of life history parameters will help determine population targets.
R2. Clarify habitat requirementsUrgentEnable identification of important or critical habitat. Better knowledge of habitat use will help focus impact mitigation and recovery efforts.
M1. Population monitoringUrgentProvide trend through time data. Improve knowledge of natural variability and population viability.  Improve ability to identify anthropogenic impacts.
MR1. Water management and conservationUrgentAvoid unnecessary degradation of western silvery minnow habitat and mortality of western silvery minnows.
MR2. Development impact mitigation
MR3. Stocking program rationalization
MR4. International cooperation
MR5. Data conservationNecessaryEnsure data and samples can be revisited if necessary.  Avoid loss of important information and unnecessary duplication of effort.
E1. Improve awareness of the speciesNecessaryImprove awareness of the western silvery minnow and its habitat.  Encourage understanding and communication with respect to the species. Reduce inadvertent harvesting and habitat destruction.
E2. Encourage stakeholder participationNecessaryImprove awareness of this species and its habitat and local support for species recovery initiatives.
E3. Facilitate information exchangeNecessaryImprove accessibility and security of data.
E4. Discourage species introductionsBeneficialReduce potential for damage to western silvery minnow populations by introduced predators and competitors.
Objective 3: To increase our understanding of how human activities affect western silvery minnow survival, so that potential threats to the species can be avoided, eliminated, or mitigated.
R4. Identify limiting factorsUrgentEnable the assessment and mitigation of threats to the species or its habitat from anthropogenic activities.
M2. Habitat monitoringUrgentProvide trend through time data. Improve knowledge of natural variability in habitat parameters.  Improve ability to identify anthropogenic impacts.
MR1-MR5 and E1-E4UrgentSee above.
  • Urgent = High priority for immediate species conservation, initiate as soon as possible.  Necessary = Medium priority for long term species conservation.  Beneficial = Lower priority, primarily directed at potential future activities.

5.4.2 Monitoring

Regular monitoring is necessary to establish trends in relative abundance of western silvery minnow, as well as to describe the availability and permanency of habitats including critical habitats once identified.  Furthermore, the physical and biological parameters of river water should be monitored regularly to track water quality.  The following strategies are recommended to address monitoring needs:

  • Population monitoring: Develop an appropriate monitoring protocol to track relative abundance, distribution and habitat use for the western silvery minnow.
  • Habitat monitoring: Routinely monitor physical environmental parameters including flow conditions, turbidity, water temperature, dissolved oxygen, nutrient loading and salinity.

5.4.3 Management and Regulation

Some management and regulatory actions are necessary to protect the western silvery minnow and its habitat.  Such actions will assist in reducing or eliminating identified threats including habitat loss and degradation, pollution, and the introduction of exotic species.  Because the recovery strategy is focused on maintenance, approaches should focus on ways to maintain and protect the species rather than rebuild the population or create new habitat.  Recommended strategies include:

  • Water management and conservation: Reduce the effects of water extraction on the western silvery minnow through appropriate water use management and conservation measures.
  • Development impact mitigation: The development of any project proposals for the Milk River must consider the potential environmental effects on the western silvery minnow as early as practical in the planning stages, and must focus on the elimination or mitigation of any potential adverse impacts on the species. Early recognition of the need for mitigation and the incorporation of appropriate measures within the project design will help to expedite project reviews and assessments.
  • Stocking program rationalization: Reduce the potential for species introductions and stocking-related impacts to western silvery minnow.
  • International cooperation: Work with US agencies to avoid unscheduled flow interruptions in the Milk River during flow augmentation.
  • Data conservation: To provide continuity and future reference, all samples and information (current and future) must be appropriately preserved and/or archived within known repositories.

5.4.4 Public Education and Outreach

Public education is essential to gain acceptance of, and compliance with the overall recovery strategy.  Public support can be gained through increased awareness of the western silvery minnow and involvement in stewardship programs. The following strategies are recommended:

  • Improve awareness of the species: Develop and distribute information describing the species and its needs, as well as implications of the recovery strategy.
  • Encourage stakeholder participation: Promote and support stakeholder involvement in stewardship initiatives.
  • Facilitate information exchange: The exchange of information among researchers, stakeholders and fisheries agencies from Canada and the United States, with regard to research, recovery and management activities related to the western silvery minnow should be facilitated.
  • Discourage species introductions: To prevent species introductions – intentional or otherwise, education programs that heighten awareness on this issue should be supported.

5.5 Critical Habitat

Critical habitat, as defined by SARA, is the “habitat necessary for the survival or recovery of a listed wildlife species”.  Its identification requires a fundamental understanding of the relationship between the species and its physical environment (or habitat), and of how changes in that habitat may affect the species' survival.  This requires basic knowledge of the habitat requirements for all life stages of the species along with information on the function, distribution, and abundance of each of these habitat types.  To date, few studies have examined the biology, life history or habitat requirements of the western silvery minnow in the Milk River or elsewhere.  Consequently, critical habitat for the western silvery minnow cannot be identified at this time.  Nonetheless, critical habitat must eventually be described and protected to ensure the conservation of the species.  To address this requirement, a proposed schedule of studies laying out the foundation for identifying critical habitat is provided in Table 4. Many of these studies have already been highlighted in the preceding section.  They include work to address gaps in knowledge of the species’ biology, life history, and habitat and to describe, locate, and inventory existing habitat types. The prescribed schedule of studies is, of necessity, a long term planning document and will be revised periodically or refined on an ongoing basis as further information warrants.

Table 4. Studies required to identify critical habitat for western silvery minnow in the Milk River.  Note that many of these studies can be conducted concurrently.
StudyTime FrameComment
Description of life history characteristicsShould be initiated immediately, expected time frame  2007-2010This is the first step necessary to address all other questions regarding habitat and should receive high priority
Description of habitat use by life stageShould be initiated in concert with the first study, expected time frame 2007-2010Such studies should include a biophysical description of habitat used by spawning, rearing, feeding and overwintering stages
Identification, location and inventory of habitatShould be initiated immediately, expected time frame  2007-2011To locate all areas within the range of the minnow that have similar features to those described in above studies, this will assist in determining the importance of habitat
Movement studiesShould be initiated as soon as practical, expected time frame 2007-2010To help determine the extent of movement for this species, particularly for spawning and overwintering purposes
Population viability analysis/modelingLikely deferred during the life of this plan (>5 years) (2012-)Such studies are necessary to provide population trend data and ultimately to establish levels of acceptable risk
Rationalization of potential critical habitatContingent on all of the above, potential time frame >5 years (2012-)Final step in determining what part of habitat should be considered “critical”

The above schedule of studies is designed to provide a comprehensive analysis of the critical habitat requirements of the western silvery minnow, but some specific elements of the species’ critical habitat may be identified earlier in the process. Such elements could include spawning and over-wintering habitats once their locations have been determined. The early and incremental identification of such habitats would help conserve the species until a more comprehensive analysis has been completed.

5.6 Effects on Non-Target Species

The proposed recovery strategy may have positive impacts on other fish species in the Milk River including the east slope sculpin (Cottus sp.) and the stonecat (Noturus flavus).  Both species are considered “Threatened” in Alberta, and the east slope sculpin was recently listed as such under SARA.  Measures directed at maintaining stream flows, preventing habitat destruction and avoiding species introductions should benefit these and other species. 

5.7 Actions Completed or Underway

A number of activities related to recovery of the western silvery minnow have already been completed.  These include:

  • In 2002, the western silvery minnow was removed as an eligible baitfish from the Alberta Fishery Regulations, 1998 (SOR/98-246).
  • In June 2004, an early summer habitat survey was conducted on the lower Milk River (Highway 880 bridge to Pinhorn Ranch) to identify possible spawning and early rearing habitat.  Possible suitable habitat locations were described but fish sampling was not conducted to confirm minnow presence.
  • Fall fish and habitat surveys were conducted opportunistically at selected sites on the lower Milk River in October and November 2004 to sample for western silvery minnow presence in potential overwintering habitat. .
  • A water conservation plan was developed by the Town of Milk River in 2004.  The plan incorporates the economics of town planning while recognizing the need for water conservation in the Milk River basin. Generally, water conservation is addressed through timing of operations and water storage.
  • Fall aerial photography was completed in October and November 2004 to document key macro-habitat sections for the entire Milk and North Milk rivers, including the entire section of river in which the minnow is found.  This survey geo-referenced and mapped key habitat features for evaluation.  Limited habitat analysis has also been conducted.
  • Signage at Writing-On-Stone Park identifying species at risk and including the western silvery minnow was completed.
  • A Milk River watershed basin advisory committee, the Milk River Watershed Council of Canada, has been established.
  • Alberta Environment conducts regular water quality monitoring on the Milk River and Environment Canada has resumed water quality monitoring at the international border, where the North Milk River enters Canada and the Milk River exits (W. Koning, pers. com.).
  • Collaboration with the Milk River MULTISAR  Program is ongoing.
  • A fact sheet describing the western silvery minnow has been completed by Fisheries and Oceans Canada.
  • Water Survey of Canada sites are well established and tracking flows (via HYDAT).
  • Fisheries and Oceans Canada sampled fish populations in the Milk River in the summer (July) of 2005 and spring (May), summer (August) and fall (October) of 2006 (D. Watkinson, pers. com.).  New data were collected on the diet, population age structure, population size structure, juvenile and adult habitat use, and distribution range of the western silvery minnow in the Milk River.
  • Fisheries and Oceans Canada has verified the taxonomic identity of western silvery minnows throughout the species’ known Canadian distribution

5.8 Evaluation and Performance

The Milk River Fish Species at Risk Recovery Team will monitor the implementation of the recovery strategy and any associated action plans for the western silvery minnow on an ongoing basis. The Team will be responsible for reviewing and evaluating the performance and implementation of recovery strategy and associated action plans, and their success in achieving the stated recovery goals and objectives.  It will meet annually over a period of five years to evaluate the success of the strategy and to recommend any changes in direction. During the fifth year, the overall recovery strategy will be re-visited to determine whether:

  • the goals and objectives are still being met;
  • the goals and objectives need to be amended; or
  • a fundamental change in approach to addressing the goals and objectives may be warranted.

Appropriate action, including amending or rewriting the strategy, will be considered at that time. Evaluations shall be based on the comparison of specific performance measures to the stated recovery objectives. Whenever possible, scientific studies will also be peer reviewed.

5.9 Action Plan Development

Implementation of the recovery strategy for the western silvery minnow shall be effected by subsequent development of an action plan, which shall be completed by 2009. The current recovery team will develop the action plan to ensure continuity and efficiency. The action plan will be reviewed on a five-year basis or as needed to respond to new information.