Squid as trophic bridges for parasite flow within marine ecosystems: the case of Anisakis simplex (Nematoda: Anisakidae), or when the wrong way can be right

Long-term (1991–1997) information on parasitic infection by anisakid nematodes in cephalopods and top predators (marine mammals) of the south-eastern area of the North Atlantic underlines the important role of small cetaceans as final hosts for A. simplex. The ommastrephid squid Illex couidetii, Todaropsis eblanae and Todarodes sagittatus are the most important cephalopod paratenic hosts in the life cycle of the parasite. Information on parasite flow and parasite-caused diseases could be of use for stock assessment purposes. Moreover, it largely agrees with what is known about interactions between prey (squid) and predator (cetacean) in the same area. Parasitic castration and stomach wall ulceration were the most important parasite-caused effects recorded in infected cephalopods and cetaceans respectively.