Yes. The cod seems to be the best adapted species for the worm. The grey seal is the best of all the seal species as a host for the worm. The adults live in the seal, then the eggs are shed and they go through a couple of invertebrate hosts, they are eaten by fish, and at that stage they stay in a certain larval stage, and it's when they're eaten again that they mature into adults in the seal. That's a cycle. Yes, they can stay for several years in the fish.
On November 9th, 2006. See this statement in context.