Description: Commercial fish species from the east Nigerian coast were examined for external lesions and flesh parasitic infections that may affect their consumability. Altogether, 2 886 specimens from 43 species representing 34 genera were sampled. The occurrence of lymphocystis disease in the pleuronectiform Cynoglossus senegalensis is here reported for the first time from an African marine teleost. Other external lesions of fishes encountered were fin rot, granulomas, pseudotumours and ulcers with total prevalences not exceeding 1%; The following commercial fish species were infected by muscle parasites at the given prevalences: Cynoglossus browni (metacercariae, 18%, Capillaria spinosa eggs, 27%; Echinocephalus sinensis L3 larvae, 9%; Philometra beninensis, 27%); C. senegalensis (Kudoa sp., 10%; metacercariae, 87%); Pseudotolithus brachygnathus (Hysterothylacium sp. larvae, 2%); P. senegalensis (Poecilancistrum cf caryophyllum plerocercoid, 1%; Philometra beninensis, 1% P. typus (Kudoa sp., 3%); Synaptura cadenati (Echinocephalus sinensis, 12%); Stromateus fiatola (trypanorhynch plerocer-coid, 44%); Epinephelus aeneus (didymozoid trematode, 44%; Hysterothylacium sp. larvae, 6%). Capillaria and Echinocephalus, representing helminths with zoonotic potential, present low risks to publie health due to their low prevalences and the local methods of preparing fish for consumption. Apart from C. spinosa eggs in soles and trypanorhynch plerocercoids in S.fiatola, none of the other flesh parasites are likely to affect the market value of their hosts at the recorded levels of occurrence. Carcharhinid sharks influence the occurrence in the locality of most fesh-parasitic helminths for which they serve as definitive hosts. The absence of the third stage larvae of zoonotic Anisakidae common in marine fishes from many other parts of the world is related to the unavailability of suitable hosts. Compared to the results from most temperate locations where similar studies have been carried out, the present study shows remarkably low prevalences and diversity for external lesions and flesh parasites in West African marine fishes

Description: The infestation of Weddell seals and several fish species by the anisakid nematodes Contracaecum osculatum and C. radiatum was compared. Nematode numbers in Weddell seal stomachs ranged from 30 560 to 122 640. Third stage larvae from seals and fish were separated into a short and a long type. The short type was related to C. radiatum and the long type to C. osculatum. The short type was more abundant in pelagic fish species, whereas the long type prevailed in benthic fish species. Fish-feeding channichthyids Cryodraco antarcticus and Chionodraco myersi seemed to play an important role as paratenic hosts for the third stage larvae of both Contracaecum species. Different advantageous and detrimental features of a benthic versus a pelagic life cycle under high Antarctic ecological conditions are discussed. Varying abundance of the two nematode species in hosts may be controlled by differences in their life cycles, which follow either a pelagic or a benthic food web. Crucial importance is thus given to the local availability of pelagic versus benthic food resources for Weddell seals.

Description: A total of 1956 fishes of 107 species from 3 regions of the Atlantic ocean were examined for larval cestodes and an identification key for larval cestodes of the order Trypanorhyncha is presented. Two species of pseudophyllid larvae were found in 5 out of 11 fish species (n=330) from the Weddell-Sea (Antarctic). Glandicephalus perfoliatus infested Chionodraco myersi (88 %), Cryodraco antarcticus (100 %), Pagetopsis maculatus (10 %) and Trematomus eulepidotus (12 %), while Diphyllobothrium sp. occurred only in Trematomus scotti (1,5 %). Nine different trypanorhynchid larval cestodes could be isolated from 14 out of 44 examined fish species (n= l120) from the Gulf of Guinea (Nigeria): Nybelinia dakari (Pomadasys peroteti (2,6 %)), Otobothrium cysticum (Arius latiscutatus (3,8); Caranx senegallus (40 %); Cynoponticus ferox (20 %); Psettias sebae (62,9 %); Pseudotolithus brachygnathus (8,6 %); P. elongatus (56 %); P. typus (19,4 %); Sphyraena guachancho (40 %)), Otobothrium dipsacum ( Petrocephalus bane (4,3 % ), Otobothrium sp. (Stroma teus fiatola (100 %)), Poecilancistrium caryophyllum (Pseudotolithus senegalensis (4,8 %)), Pseudogrillotia perelica nov. comb. (Caranx senegallus (81,8 %)), Pterobothrium sp. (Galeoides decadactylus (3,2 %)), Tetrarhynchobothriidae (Epinephelus aeneus (12,5 %)) and one unidentified trypanorhynchid larva from Galeoides decadactylus (3,2 %). Two tetraphyllid and eight trypanorhynchid larval cestodes were found in 12 out of 52 fish species (n=506) from the north-east Brazilian coast: Calli tetrarhynchus qracilis (Caranx crysos (25 %); Harengula clupeola (33,3 %); Oligoplites palometa (14,3 %); Opisthonema oglinum (40 %); Scomberomorus maculatus (28,6 %); Selene vomer (20 %)), Lacistorhvnchus sp. (Haemulon aurolineatum (9,1 %), Pseudupeneus maculatus (83,3 %); Scomberomorus maculatus (14,3 %)), Nybelinia sp. I (Haemulon plumieri (10 %); Pseudupeneus maculatus (20 %); Selene vomer (20 %)), Nybelinia sp. II (Pseudupeneus maculatus (10 %)), Nybelinia sp. III (Pseudupeneus maculatus (10 %)), Otobothrium cysticum (Scomberomorus maculatus (42,9 %)), Otobothrium dipsacum (Pseudupeneus maculatus (16,7 %)), Rhinebothrium sp. (Gobionellus oceanicus (15,4 %)), Scolex pleuronectis (Hyporhamphus unifasciatus (6,7 %)) and one unidentified trypanorhynchid larva from Lutjanus analis (16,7 %). Lacistorhynchus sp. is supposed to be a new species. Plerocercoids of Pseudophyllids, Tetraphyllids and Trypanorhynchs are the predominant cestode larvae in marine fishes. They are mainly found in the body cavity of their intermediate fish hosts. However, Trypanorhynchs of the families Grillotiidae, Gymnorhynchidae, Lacistorhynchidae, Otobothriidae and Pterobothriidae are the most frequent findings in the muscle. In the present study, three larval trypanorhynch cestodes (Lacistorhynchus sp. (Lacistorhynchidae); Otobothrium sp. and Poecilancistrium caryophyllum (Otobothriidae) could be found in the muscle of the fish examined. The occurrence of larval cestodes in different regions of the Atlantic ocean depends on the distribution of their final hosts. In polar regions larval Pseudophyllidea (final hosts: seals, whales) are the dominant order, while Trypanorhyncha (final hosts: sharks, rays) occur mainly in the tropics. In contrast, all 3 orders (Pseudophyllidea, Tetraphyllidea, Trypanorhyncha) can be found in the boreal zone of the Atlantic. The distribution of larval cestodes which are potentionally pathogenic for man is limited to the polar and boreal zones. However, they occur with low prevalences and cause only little thread to the public health. In the tropics, even the consumption of raw fish bears no risk, because all isolated larval cestodes belonged to the order Trypanorhyncha, which use sharks and rays as their final hosts.