MWCS Supports Bighorn Sheep Restoration

kylestelter
Dec 17, 2025
3 min read

Landscape-Level Disease Mitigation for B.C.’s California Bighorn Sheep

Mountain Wildlife Conservation Society is proud to support a major, multi-region effort to reduce disease impacts and strengthen long-term resilience for California bighorn sheep in southern British Columbia.

Led by Jeremy Ayotte (Project Lead), Phyla Biological Consulting Inc., this initiative unites active research and on-the-ground management into one coordinated program—so partners can share data, align actions, and accelerate learning across B.C.’s bighorn range.

Funding request: $55,000

Why this project matters

California bighorn sheep populations in B.C. face complex and overlapping health threats that can suppress lamb survival, limit recruitment, and slow recovery for years. This project focuses on practical, science-based strategies that can be applied at the landscape level, while also improving the tools and partnerships needed to respond quickly as conditions change.

What the project will do

This grant application brings together three major components already underway in wild sheep range in B.C.:

1) Fraser River Test-and-Removal (T&R) — Year 7

B.C.’s first and only Test-and-Removal program continues to show promising outcomes for reducing Mycoplasma ovipneumoniae (M. ovi) and supporting recovery of Canada’s largest California bighorn metapopulation.

In Year 7, the project team plans to:

Capture and sample approximately 70–80 adult ewes (drop-net or helicopter capture depending on conditions)
Use rapid field diagnostics (Biomeme PCR) to identify M. ovi status
Remove clearly positive individuals to break transmission from carrier ewes to lambs
Compare lab results from multiple diagnostic sources to improve consistency and understanding across testing methods
Monitor outcomes through lamb surveys and follow-up sampling of yearlings in the year after treatment

2) Fraser River post-treatment herd management

Following seven years of intensive work, some Fraser River subpopulations are now small and vulnerable—even after disease-positive ewes have been removed. This component focuses on recovery actions to help these remnant groups persist and rebuild.

Actions may include:

Prioritizing short- and medium-term recovery measures
Supporting targeted predator management approaches where appropriate
Preparing habitat enhancement prescriptions and identifying restoration priorities
Assessing opportunities for augmentation/translocation consistent with B.C. policy and procedures

3) South Okanagan disease mitigation and monitoring

In the South Okanagan, bighorn sheep face multiple disease threats, including M. ovi respiratory disease, psoroptic mange, and hemorrhagic diseases such as bluetongue and epizootic hemorrhagic disease.

This component will strengthen monitoring and decision-making by:

Using GPS collars and a trail camera grid to understand herd interactions and potential transmission pathways
Developing a risk model to identify higher-risk herds and prioritize response
Expanding sampling to improve herd health metrics, fecundity, lamb survival, and demographic trend detection
Supporting improved mange detection through ELISA antibody testing (in collaboration with Moredun Research Institute)

This work is also strongly supported by partners and contributes to broader, coordinated efforts to address wildlife health concerns in the region.

Objectives and measures of success

Fraser River T&R (Year 7)

Increase lamb survival and lamb:ewe ratios
Support sustained population growth
Confirm no evidence of M. ovi exposure in yearlings following treatment (PCR + blood serology)

Fraser River post-treatment management

Maintain and recover healthy, M. ovi-free subpopulations
Improve habitat and forage quality in priority areas
Support resilience and local movement patterns over the long term

South Okanagan disease mitigation

Improve detection of psoroptic mange using ELISA, camera grids, and capture/sampling
Better understand herd connectivity (including cross-border interactions)
Increase the quantity and quality of herd health samples
Identify viable, policy-compliant opportunities for population augmentation where appropriate

Collaboration and partners

A key strength of this initiative is the collaboration across regions, agencies, and communities. Project collaborators include:

Chris Procter (B.C. Government, Region 3, Senior Wildlife Biologist)
Mackenzie Clarke (Okanagan Nation Alliance, Senior Wildlife Biologist)
Bill Jex (B.C. Government, Provincial Wild Sheep & Mountain Goat Specialist)
Andrew Walker (B.C. Government, Region 8, Senior Wildlife Biologist)

The project team also works closely with wildlife health experts and follows recognized standards and protocols to ensure methods and findings support strong, defensible management decisions.

Timeline (project window)

Fall 2024 to Spring 2025 overall program window
Fraser River T&R capture and lab work: March–April 2025
Fraser River monitoring: late-fall lamb surveys (e.g., November flights) and yearling sampling the following year
Fraser post-treatment actions: late winter/spring 2025
South Okanagan capture/collar/sampling: winter 2025
ELISA development and validation for Psoroptes: by spring 2025
GIS analyses and risk modeling: by June 2025

How MWCS funds will be used (requested total: $55,000)

MWCS support will help cover high-impact field operations and key analyses, including:

Fraser River T&R (Year 7): helicopter services for capture, sampling, lamb counts, and mortality investigations
Fraser post-treatment management: planning and implementation support (e.g., lambing site identification, predator management guidance, habitat prescription development, prioritizing restoration areas, and assessing augmentation needs under policy)
South Okanagan disease work: helicopter services for capture/collar/sampling and mortality investigations; lab analyses and ELISA development support where required