Scientists Identify First Transmissible Cancer in Freshwater Catfish, Raising Environmental Concerns
Researchers have discovered the first known instance of a transmissible cancer in freshwater fish, specifically in brown bullhead catfish in Lake Memphremagog, which spans the border of Vermont and Quebec. This finding emerged after anglers and biologists noticed catfish with raised black spots, later identified as melanoma lesions, affecting 23% to 37% of the sampled fish. Initially, environmental factors such as pollution from past flooding events were suspected. However, the study, published in Nature, suggests that cancer cells are transferring directly from one catfish to another. This marks a significant discovery as it is the first known transmissible cancer in fish and the first identified in a freshwater setting. 
