Catfish in Vermont Lakes Harbor a Rare Transmissible Cancer

Scientists have identified a clonally transmissible melanoma spreading among brown bullhead catfish in Lake Memphremagog and nearby waters across Vermont, New Hampshire, Maine, and New Brunswick, making it the fourth known naturally occurring transmissible cancer. The cancer cells move between fish through close contact (especially during spawning) and possibly via contaminated water or sediment. There is no known risk to humans, but the outbreak could affect local catfish populations and ecosystem health as researchers study its distribution and origins.