What tiny worms found in decades-old cans of salmon reveal about marine ecosystems Think Out Loud

In the spring of 2021, Natalie Mastick, a graduate student in the University of Washington’s School of Aquatic and Fishery Sciences, dissected filets from nearly 200 cans of salmon, some of which were more than 40 years old. The cans contained filets from pink, chum, coho and sockeye salmon that were caught in Alaska between 1979 and 2021. Mastick acquired the cans from the archives of the Seafood Products Association, a trade organization based in Seattle that provides quality control testing to seafood processors.

Mastick and her colleagues opened up the cans to look for the presence of a parasitic roundworm embedded inside the filets. The parasite requires multiple hosts, including salmon, to complete its life cycle. Its abundance can serve as an indicator of the health of the marine food web, and how infections are changing over time for species like salmon and killer whales. Mastick is now a postdoctoral associate of student programs at the Yale Peabody Museum. She joins us to talk about her recently published findings.