Animal health directly impacts our health. Our food, our water, our environment, and our economy are reliant on healthy fish and wildlife. The USGS is the lead federal agency for wildlife disease research and surveillance. Our wildlife health work focuses largely on the prevention and detection of disease in wild game species, fishes, and other wildlife.  We also play an important role in disease outbreak responses for humans. 

Friday, April 25, 2025 marks the inaugural USGS Wildlife Health Awareness Day.  In celebration, we're hosting a special one-hour Friday's Findings focused on USGS wildlife health science. 

Presentations include:

Behavioral Responses and Keystone Interdependence: How the Loss of Sea Stars Reveals Complex Relationships Between Predators and Prey in Adjacent Nearshore Marine Ecosystems

Joseph Tomoleoni
Biologist, USGS Western Ecological Research Center, Santa Cruz, CA

In 2013, numerous species of sea stars experienced a rapid and dramatic decline in abundance along the west coast of North America due to Sea Star Wasting Disease (SSWD). Two of the hardest hit species, the sunflower star (Pycnopodia helianthoides) and the ochre star (Pisaster ochraceus), are major predators of sea urchins and mussels, respectively, in kelp forests and intertidal habitats. The near extirpation of these two sea stars led to large increases in abundance and habitat use by purple sea urchins (Strongylocentrotus purpuratus) and California mussels (Mytilus californianus). Urchins, in particular, are known to cause dramatic shifts in ecosystem state when overabundant, whereby kelp forests are overgrazed and replaced by urchin barrens. Our research shows that in central California, southern sea otters (Enhydra lutris nereis) were able to respond to the sudden abundance of their urchin and mussel prey by increasing their consumption of these species. In doing so, local populations of the threatened southern sea otter also increased, demonstrating that the loss of a keystone predator in one ecosystem may impart population-level changes in another. By altering their diet to consume greater amounts of urchin and mussel prey, sea otters helped mitigate the negative impacts to kelp forest and intertidal ecosystems brought on by the unchecked population growth of urchins and mussels. While sea otters may not be able to single-handedly make up for the loss of sea star predators in these ecosystems, their presence and behavioral responses to large-scale perturbations highlight their importance in ecosystem resilience.

Plague: Invasive Ecosystem Transformer in the Western USA

David A. Eads
Research Ecologist, USGS Fort Collins Science Center, Fort Collins, CO

The plague bacterium Yersinia pestis was introduced to the western United States in the year 1900. One striking aspect of Y. pestis - a primarily flea-borne pathogen - is its ability to spread explosively during epizootics, killing >90% of individuals in some mammal populations, sometimes within weeks to months. These generative events allow Y. pestis to proliferate and spread in mammal communities. Just as striking is the fact that these intervals of intense transmission are followed by longer periods of enzootic plague, in which Y. pestis kills hosts at lower but ecologically significant levels, thereby causing chronic reductions in mammal populations. This presentation will summarize current knowledge on the enduring threat posed by plague in western USA. Case examples will illustrate how plague impacts populations of mammals and transforms ecological relationships in ways to further degrade biological systems. Eradication of plague is difficult to impossible, but effective mitigation can be achieved via flea vector control. New methods of flea control - designed for affordable and rapid field application - will be discussed.

Wildlife Health Awareness Day: USGS Science to Support Free-Ranging Wildlife Health

Camille Hopkins DVM, MS, PhD, DACVPM
Fish and Wildlife Disease Research Coordinator
Biological Threats and Invasive Species Research Program, USGS Ecosystems Mission Area

Wildlife conservation efforts often include health assessments.   While wildlife populations can successfully coexist with many parasites and pathogens, there are significant diseases that impact population health and potentially ecosystems.  As Aldo Leopold wrote in Game Management, the “role of disease in wildlife conservation has probably been radically underestimated.”  This presentation will highlight examples of USGS science to understand and identify interventions for diseases that have significant ramifications for free-ranging wildlife health.