Pollutants are widely distributed by the atmosphere and the oceans. Contaminants can also be transported by salmon and amplified through the food chain. Here we show that groups of migrating sockeye salmon (Oncorhynchus nerka) can act as bulk-transport vectors of persistent industrial pollutants known as polychlorinated biphenyls (PCBs), which they assimilate from the ocean and then convey over vast distances back to their natal spawning lakes.

— Excerpt from the paper