Researchers found more parasites in salmon than forty years ago. This is not a cause for concern, but rather a sign of a recovering ecosystem.
The worms are harmless to humans if they are killed during the preservation process. Anisakis larvae or fully formed anisakids enter the food web when they are eaten by krill. They get into the salmon and eventually into the intestines of marine mammals, where the worms complete their life cycle by reproducing. Their eggs are released into the sea by the mammals and the cycle begins again. The parasites were able to find the right hosts and reproduce and this could indicate a stable or recovering ecosystem in which there are enough suitable hosts for the worms to reproduce. The study’s lead author Natalie Mastick and her colleagues believe this novel approach could lead to many more scientific archive as many old canned salmon could be used as an ecological tool for future research. The cans had been set aside for decades as part of the association's quality control process. The 178 cans in the “Archive” included four different species of salmon.