Story perspectives

Lake Memphremagog catfish host fourth transmissible cancer

7/23/2026

Summary

Story summary

Researchers led by Julie Dragon confirmed a transmissible melanoma in bullhead catfish in Lake Memphremagog.
By 2014, about one-third of catfish in Lake Memphremagog displayed black lesions.
Sequencing showed tumor cells share hundreds of thousands of variants, contain arsenic, and confirm a clonal transmissible cancer—the fourth known.
Scientists said the disease cannot infect humans or other species, poses no health threat, and they are testing lakes for spread in spawning or sediment.

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Story summary

Researchers led by Julie Dragon confirmed a transmissible melanoma in bullhead catfish in Lake Memphremagog.
By 2014, about one-third of catfish in Lake Memphremagog displayed black lesions.
Sequencing showed tumor cells share hundreds of thousands of variants, contain arsenic, and confirm a clonal transmissible cancer—the fourth known.
Scientists said the disease cannot infect humans or other species, poses no health threat, and they are testing lakes for spread in spawning or sediment.