Exploring Disease Susceptibility and Its Impact on Lake Whitefish Recruitment

photo credit: B. Yokom & Dr. T. Loch, Michigan State University – Aquatic Animal Health Laboratory; Project funded by the Great Lakes Fishery Trust, Project No. 2018.1806

Exploring Disease Susceptibility and Its Impact on Lake Whitefish Recruitment

Lake whitefish abundance, growth, and recruitment have all been on the decline in the Great Lakes since the early 2000s. To understand factors that may be contributing to low recruitment in this important species, GLFT-funded researchers investigated the pathogens causing infections in adult and juvenile lake whitefish, and the fish’s susceptibility to some diseases in laboratory settings. Data from this study can potentially be used to inform population models of lake whitefish with better estimates of mortality, and could, in the long term, be used as the basis for a variety of fish health interventions.

Led by Dr. Thomas Loch of Michigan State University, the research team sampled lake whitefish from sites in Lakes Michigan, Huron, and Superior to determine which pathogens were present in their tissues. The research team also raised juvenile lake whitefish in a lab and tested their susceptibility to infection and disease when exposed to pathogens found in wild whitefish.

Key Findings

Renibacterium salmoninarum (the cause of bacterial kidney disease) infections were more common in adults sampled from sites with historically low recruitment than in those sampled from sites with historically high recruitment. This bacterium was also detected in the gonads of some fish, which is notable because R. salmoninarum can be transmitted from parent to offspring in other salmonid species.
Flavobacterium psychrophilum, which causes bacterial coldwater disease and is also transmitted from parent to offspring in other salmonid species, was recovered from infected adult lake whitefish for the first time.
Carnobacterium maltaromaticum (cause of pseudokidney disease) was detected in the gonads and kidneys of adult lake whitefish, and infections were frequently more common in adults collected from sites with historically poor recruitment.

Significant Outcomes for Lake Whitefish Research

This research project uncovered important new knowledge about the pathogens and diseases of Great Lakes whitefish. Although further research is needed, results suggest that some bacterial infections, especially those that can be passed from parent to offspring, could play a role in depressing lake whitefish recruitment.

Learn More

If you have questions, please contact the primary investigator, Dr. Thomas Loch, at [email protected].

Disclaimer

Research Notes includes the results of GLFT-funded projects that contribute to the body of scientific knowledge surrounding the Great Lakes fishery. The researcher findings and grant result summaries do not constitute an endorsement of or position by the GLFT and are provided to enhance awareness of project outcomes and supply relevant information to researchers and fishery managers.