Scientists have discovered an innovative method to study the evolution of marine ecosystems in Alaska over the past four decades: canned salmon.
Photo of an Anisakis parasite worm — highlighted in red — in a canned salmon fillet.
Credit: Natalie Mastick/University of Washington
Natalie Mastick, a postdoctoral researcher at the Peabody Museum of Natural History at Yale University, led a team that examined 178 cans of salmon. These cans contained fillets from four salmon species, caught over a period of 42 years in the Gulf of Alaska and Bristol Bay. Their goal? To count Anisakis worms, common marine parasites, to assess the health of the marine ecosystem.
The study, published on April 4th in
Ecology & Evolution, reveals that the number of Anisakis worms has increased for chum and pink salmon from 1979 to 2021, while it has remained stable for coho and sockeye salmon. These results could indicate stable or recovering ecosystems, with a marine food chain robust enough to support the complex life cycle of Anisakis.
Anisakis have a complex life cycle that requires several types of hosts, from small marine invertebrates like krill to marine mammals where they reproduce. The increased presence of these parasites could also reflect the positive effects of the 1972 Marine Mammal Protection Act, which allowed many marine mammal species to recover after years of decline.
A severely degraded Anisakis parasite recovered from canned salmon. The scale bar measures 0.02 inches (0.5 millimeters).
Credit: Natalie Mastick/University of Washington
This approach could be extended to other canned fish, such as sardines, paving the way for new discoveries about past ecosystems.