This work summarizes information on parasites of 91 species of fish from personal knowledge and available literature (Karasev, 2003). There are 10 types of parasites found in the fish of the Barents Sea: Mastigophora (Kinetoplastomonada, Parasitomonada), Sporozoa (Coccidea), Microsporidia (Microsporea), Myxozoa (Myxosporea), Ciliophora (Peritricha), Plathelminthes (Monogenoidea, Gyrocotylida, Cestoda, Aspidogastrea, Trematoda), Nemathelminthes (Nematoda), Acanthocephales (Palaecanthocephala), Annelida (Hirudinea), Arthropoda (Crustacea) – total of 235 species, from 140 genera , 74 families, 33 groups, 15 classes (see Table 2.4.4).
It is hard to determine which groups of parasitic organisms that play an important role in the population dynamics of their hosts. If there are large changes in the ecosystem, several groups of infectious organisms are capable of causing unpredictable effects on the ecosystem, including serious declines in host population.
The parasites found in the Barents Sea parasites that are considered the largest potential threats to human health are larvae stages of Cestoda (Diphyllobothrium and Pyramico-cephalus genera), Nematoda (Anisakis and Pseudoterranova genera) and Palaea canthocephala (Corynosoma genera). Only nematode larvae of Anisakis and Pseudoteranova genera are present in the fish muscles tissue (Korotaeva, 1991; Serdyukov, 1993; Solovyeva, Krasnyh, 1989).
According to current research, levels of parasitic infestation in fish with organisms that are potentially dangerous for human health, has not increased in recent years. In some cases there is even a decrease in infestation level. This may be a result of an improving state of the capelin stock, which is often the main food base for the commercially important fish species.