EVALUATING RISK OF LEAD EXPOSURE IN SCAVENGING SPECIES LINKED TO BIG-GAME HUNTING IN SASKATCHEWAN, CANADA

For free-ranging animals, chronic exposure to lead, a toxic heavy metal, can manifest in discrete physiological changes, alter behaviours, and contribute to increased mortality. In Canada, although lead ammunition has been banned for hunting waterfowl, carrion contaminated with lead fragments from bullets used in rifle-hunting remains a potential source of exposure for wildlife, particularly scavenging species. Addressing these risks requires clearer understanding of both the source (rifle-harvested remains) and the consumers (scavengers). The objective of my research was to evaluate the risk of lead exposure to scavenging wildlife in Saskatchewan, Canada, by investigating the detection and quantification of lead in hunted animal remains (Chapter 2) and assessing scavenger community assemblages at kill sites (Chapter 3). In Chapter 2, I compared advanced imaging techniques (Biomedical Imaging and Therapy) with traditional medical x-rays to identify limitations in detecting and quantifying lead fragments in undesired animal tissues, such as viscera and organs (i.e., offal), left in the field by hunters. I also conducted a coarse geospatial analysis using provincial hunter harvest data to determine regions in the province where scavengers may face elevated lead exposure risks. In Chapter 3, I examined scavenger species assemblages observed feeding on white-tailed deer (Odocoileus virginianus) kill sites and analyzed how environmental factors influenced community composition and species richness. My findings revealed that medical x-rays underestimated lead exposure risk due to their limited spatial resolution, missing small, bioavailable fragments and misrepresenting fragment size. The geospatial analysis showed that hunter harvest densities for white-tailed deer and mule deer varied significantly across wildlife management zones, potentially influencing exposure risks for scavengers by means of offal-derived lead. Scavenger community analyses showed that snow depth influenced community assemblage, while ecoregion and minimum daily temperature significantly predicted species richness at kill sites. This research advances the understanding of lead contamination from big-game hunting and highlights key factors that influence scavenger exposure. These findings offer valuable insights to guide future management strategies aimed at reducing or mitigating lead exposure risks across the landscape.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Biology

Grantor

University of Saskatchewan

Year dc:date.issued

2025

Author dc:creator

• Bent, Lynsey C

Advisor dc:contributor.advisor

• Gurney, Kirsty

Committee members dc:contributor.committeemember

• Bahr, Jim
• Weegman, Micth
• Mehl, Katherine
• Benson, James

• Lead
• Lead Ammunition
• Big-game Hunting
• Lead Exposure

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10388/16738

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/16738