Dall Sheep Health Monitoring: Heavy Metals and Trace Elements

In response to local concerns over declining Dall sheep populations, AITRC is conducting a pilot study measuring heavy-metal and trace-element concentrations in hunter-harvested Dall sheep from GMUs 11 and 13. By collecting voluntary biological samples from hunter-harvested sheep, researchers can assess concentrations of essential and nonessential elements in tissue and identify patterns of possible exposure that warrant further investigation.

This research helps establish baseline health information for Dall sheep populations, supporting long-term wildlife monitoring, informed management decisions, and the continued availability of this important subsistence resource for future generations.

Get Involved

Funded by First Nations Development Institute through the Restoring Our Relatives initiative.

Why Monitor Dall Sheep Health?

In recent years, Tribal and local hunters have raised concerns about Dall sheep populations across the Ahtna Territory. Dall sheep are an important wildlife species throughout Alaska, providing subsistence opportunities and contributing to the cultural traditions and food security of our communities.

Dall sheep inhabit remote mountainous environments, where their health and survival can be influenced by changes in habitat conditions, food availability, disease, and environmental exposure. Because these animals live in areas that can be difficult to access, obtaining biological information about their health can be challenging.

Through this project, AITRC is working to establish baseline information that can help researchers:

Identify health questions that warrant future disease or parasite testing.
Identify follow-up questions concerning diet and nutrition where appropriate assays are available.
Measure concentrations of essential and nonessential elements in biological tissues.
Explore geographic and tissue-specific patterns in elemental exposure.
Support long-term monitoring and wildlife management throughout the Ahtna Territory.

Hunter-Donated Biological Samples.

The Dall Sheep Health Monitoring Project began as a pilot in 2025, using voluntarily donated samples from legally harvested animals; a second sampling round occurred in the 2026 hunting season.

Collecting samples from harvested sheep allows researchers to gather valuable health information without requiring additional animals to be captured or harvested specifically for the study.

AITRC collects several types of biological samples, each providing different information about sheep health and environmental exposure: Liver, kidney, muscle tissue, hair, fecal, and nasal swabs. Together, these samples provide a more comprehensive picture of individual sheep health and help researchers investigate potential concerns across the population.

Essential and Nonessential Elements.

Funded Laboratory Methods. With support from First Nations Development Institute through its Restoring Our Relatives program, AITRC will analyze approximately 20 elements by inductively coupled plasma mass spectrometry (ICP-MS), including cadmium, lead, arsenic, mercury, copper, and selenium. Differences among muscle, liver, and kidney tissues may inform exposure patterns but cannot by themselves diagnose toxicity or explain a population decline.

Dall sheep encounter naturally occurring elements through the plants, soil, and water in their environment. Some elements are essential for normal biological functions, while others may be harmful at elevated concentrations. By analyzing tissue samples, researchers can evaluate the presence and concentrations of these elements and better understand potential environmental exposure. This research can help identify patterns that may warrant additional investigation and contribute to a broader understanding of wildlife health throughout Ahtna Territory.

Supporting Long-Term Wildlife Management.

The Dall Sheep Health Monitoring Project is an important step toward establishing baseline health information for sheep populations within the Ahtna Territory.

As laboratory results become available, this work can establish baseline elemental concentrations, identify geographic or tissue-specific differences, and guide questions requiring further wildlife-health or public-health review. It is not, by itself, a food-consumption advisory.

By combining scientific research with local knowledge and hunter participation, AITRC works to strengthen Tribal involvement in wildlife research and support the long-term stewardship of Dall sheep populations.

Get Involved!

Do you go sheep hunting? Hunters planning to harvest Dall sheep in the project area can pick up a free sampling kit from the AITRC office before the hunting season. Each kit contains collection materials, storage bags, a harvest form, and instructions. After collection, samples should remain frozen until they are delivered to AITRC.

This research would not be possible without the participation of Tribal and local hunters. Hunters contribute both biological samples and valuable harvest information, including the harvest location, estimated age, body condition, observed deformities, and the number and types of sheep seen during the hunt.

AITRC uses this information for research and data analysis. Personal information provided on collection forms is kept private and is not shared. Tsin’aen to the hunters who contribute their time, knowledge, observations, and samples to this project. Their participation is helping AITRC build a stronger understanding of Dall sheep health in Ahtna Territory.

Project Leads: Sterling Spilinek | Questions on this project?