Description: The deep-sea smelt Bathylagus euryops, caught in July 2004 at the Charlie-Gibbs Fracture Zone (CGFZ) of the Mid-Atlantic Ridge (North Atlantic), was studied for metazoan parasites and diet composition. A total of 86 specimens with standard lengths between 6.4 and 22.1 cm (mean 13.6 cm) were examined. The parasite fauna consisted of five species: three Digenea, one Cestoda and one Nematoda. The predominant parasites were Lecithaster sp. (Digenea) and an unidentified bothriocephalidean cestode. The only nematode, Anisakis sp., occurred with a low prevalence. Bathylagus euryops at CGFZ serves as final host for the three digeneans, and as intermediate host for the cestodes and Anisakis sp. Stomach content analysis revealed a mesozooplankton crustacean diet, while 95.3% of the stomachs contained unidentified tissue.

Description: Silver scabbard fish Lepidopus caudatus (Euphrasen, 1788) (Trichiuridae) from the Great Meteor Seamount (GMS) in the central eastern Atlantic were studied for diet composition and metazoan parasites. A total of 36 specimens with lengths between 39.1 and 52.2 cm were sampled, which had taken 14 different prey items belonging to 4 major taxonomic groups (Chaetognatha, Crustacea, Mollusca and Teleostei). The most abundant prey organisms were Myctophidae and Euphausiacea, followed by Copepoda (Calanoida), Decapoda, Chaetognatha and Cephalopoda. Fishes were also the dominant prey in terms of biomass. Cannibalism was observed in 7 specimens of subadult L. caudatus. A total of 11 parasite species were identified in/on L. caudatus. We established 9 new host and 8 new locality records. Infestation rates were congruent with diet composition, indicating that parasites were ingested via mesopelagic prey organisms serving as intermediate hosts. The rich parasite fauna in L. caudatus reflects a high diversity of mesopelagic species at the GMS, providing niches for parasites and their intermediate hosts. While several species such as Paradiplectanotrema lepidopi (Monogenea) and Nybelinia lingualis (Cestoda) are typical parasites of L. caudatus, other species such as Sphyriocephalus tergestinus (Cestoda), Anisakis simplex (Nematoda) and Bolbosoma vasculosum (Acanthocephala) seem to be transferred by hosts migrating into the area, indicating an important role of the GMS in the transoceanic distribution patterns of such parasites

Description: Tintenfische oder Kopffüßer (Cephalopoda) gehören unbestritten zu den eindrucksvollsten Aquarientieren. Sie sind die einzigen Wirbellosen, die mit dem Menschen zu "kommunizieren" vermögen.

Description: The aim of the study was to examine metazoan parasite communities of European eels (Anguilla anguilla) in fresh-water, brackish water and marine localities in northern Germany. In all, 29 parasite species/taxa were found in 170 eels: eight digeneans, one monogenean, five cestodes, ten nematodes, two acanthocephalans, and three crustaceans. Measures of diversity characteristics of the helminth communities included species richness, Shannon's diversity index and its evenness, and the Berger–Parker dominance index. The highest species diversity and lowest dominance values were calculated for the helminth communities of eels from the two Baltic Sea localities. Parasite communities of European eels clearly exhibit the habitat preferences of their hosts, salinity-dependent specificities, and a clustering into fresh-water, brackish, and marine groups. The highly pathogenic parasite species Anguillicola crassus and Pseudodactylogyrus spp. were found at all sampling sites in fresh water and brackish water, with high prevalence. Basic information is provided on the risks of restocking programmes solely focusing on fresh-water sites.

Description: A total of 37 juvenile Etmopterus spinax from the Norwegian Deep were examined for stomach contents and metazoan ecto- and endoparasites. These squaliform elasmobranchs were caught by benthopelagic net in May 2001 at a depth of 194–214 m. The euphausiid Meganyctiphanes norvegica and the teleost Maurolicus muelleri were the principal prey organisms. With increasing total length of E. spinax, the frequency of Meganyctiphanes norvegica prey decreased and that of M. muelleri increased. Seven different metazoan parasite species were found: adult Monogenea (2), larval and adult Cestoda (3), and larval Nematoda (2). The predominant parasites were an unidentified monocotylid monogenean and the cestode Aporhynchus norvegicus, with respective prevalences of infestation of 83.8% and 81.1%. The sites of infestation were the gills (Squalonchocotyle spinacis, Monogenea), nasal cavities (Monocotylidae indet.), body cavity (Lacistorhynchus tenuis, Cestoda), stomach wall and organs of the body cavity (Anisakis simplex, Nematoda), and stomach and spiral valve (A. norvegicus and Pseudophyllidea indet., Cestoda; Hysterothylacium aduncum, Nematoda). No other metazoan parasite taxa were found, and the musculature was free of parasites. Five new host and three new locality records were established. M. muelleri seems to be an important intermediate host for the endoparasitic nematodes which were found, with E. spinax serving as a paratenic host. E. spinax also serves as an intermediate host for the trypanorhynch cestode L. tenuis, and as the definitive host for the two monogeneans and the trypanorhynch A. norvegicus. The latter uses Meganyctiphanes norvegica as the second intermediate host in the Norwegian Deep. The relationship between the feeding ecology, habitat, and vagility of E. spinax and the resulting parasite fauna is discussed.

Description: Copepoda (Calanus finmarchicus n=1,722, Paraeuchaeta norvegica n=1,955), Hyperiidae (n=3,019), Euphausiacea (Meganyctiphanes norvegica n=4,780), and the fishes Maurolicus muelleri (n=500) and Pollachius virens (n=33) were collected in the Norwegian Deep (northern North Sea) during summer 2001 to examine the importance of pelagic invertebrates and vertebrates as hosts of Anisakis simplex and their roles in the transfer of this nematode to its final hosts (Cetaceans). Third stage larvae (L3) of A. simplex were found in P. norvegica, M. muelleri and P. virens. The prevalence of A. simplex in dissected P. norvegica was 0.26%, with an intensity of 1. Prevalences in M. muelleri and P. virens were 49.6% and 100.0%, with mean intensities of 1.1–2.6 (total fish length ≥6.0–7.2) and 193.6, respectively. All specimens of C. finmarchicus and M. norvegica examined were free of anisakid nematode species and no other parasites were detected. P. norvegica, which harboured the third stage larvae, is the obligatory first intermediate host of A. simplex in the investigated area. Though there was no apparent development of larvae in M. muelleri, this fish can be considered as the obligatory second intermediate host of A. simplex in the Norwegian Deep. However, it is unlikely that the larva from P. norvegica can be successfully transmitted into the cetacean or pinniped final hosts, where they reach the adult stage. An additional growth phase and a second intermediate host is the next phase in the life cycle. Larger predators such as P. virens serve as paratenic hosts, accumulating the already infective stage from M. muelleri. The oceanic life cycle of A. simplex in the Norwegian Deep is very different in terms of hosts and proposed life cycle patterns of A. simplex from other regions, involving only a few intermediate hosts. In contrast to earlier suggestions, euphausiids have no importance at all for the successful transmission of A. simplex in the Norwegian Deep. This demonstrates that this nematode is able to select definite host species depending on the locality, apparently having a very low level of host specificity. This could explain the wide range of different hosts that have been recorded for this species, and can be seen as the reason for the success of this parasite in reaching its marine mammal final hosts in an oceanic environment.