Stomach contents of 17 sperm whales Physeter rnacrocephalus stranded in Scotland and Denmark during 1990-96 were analysed. All were sub-adult or adult males and stranded between November and March. They had presumably entered the North Sea during their southward migration from feeding grounds in Arctic waters. Other studies indicate that the majority of the whales were apparently healthy. The diet of these whales was found to consist almost entirely of cephalopods, principally squid of the genus Gonatus (hereafter 'Gonatus', but probably G. fabncii, an oceanic species characteristic of Arctic waters). The other prey species identified were also mostly oceanic cephalopods: the squids Hjstioterlthis bonnellii, Teuthowenia megalops and Todarodes sagjttatus and the octopus Hahphron atlanticus. Although these results are consistent with other recent studies in the area based on single stranded whales, they chffer from results of work on whales caught during commercial w h a h g operations in Icelandic waters (1960s to 1980s) in that little evidence of predation on fish was found in the present study. Remains of single indviduals of the veined squid LoLigo forbesi, the northern octopus Eledone cirrhosa and the saithe PoUachius virens provided the only possible evidence of feeding in the North Sea. We infer that sperm whales do not enter the North Sea to feed. The timing, and large and uniform sizes of the Gonatus species eaten (most had mantle lengths in the range 195 to 245 mm), as estimated from measurements of the lower beaks, and the seasonality of the strandings is consistent with the whales having fed on mature squid, possibly spawning concentrations-as has recently been reported for bottlenose whales. Assuming that the diet recorded in this study was repre sentative of sperm whales during the feeding season, as much as 500000 t of Gonatus could be removed by sperm whales in Norwegian waters each year and up to 3 times that figure from the eastern North Atlantic as a whole. Evidence from other studies indicates that Gonatus is an important food resource for a wide range of marine predators in Arctic waters.

The stomach of a female northern bottlenose whale, Hyperoodon ampullatus (Odontoceti: Ziphiidae) stranded at Hiddensee Island, western Baltic Sea, on 23 August 1993 contained 7465 cephalopod beaks (4934 upper and 2531 lower). The lower beaks were identified, their rostral lengths were measured and used to estimate size and mass of the cephalopods consumed by the whale. All lower beaks belonged to one species, the boreoatlantic gonate squid Gonatus fabricii (Cephalopoda: Teuthoidea) indicating a mean squid mantle length of 21·9 cm and a mean squid wet mass of 220·7 g. The total squid biomass in the whale's stomach represented by the lower beaks was 598·6 kg. Assuming that all upper beaks belong to G. fabricii, the squid biomass taken by the whale was estimated to be 1089 kg. Besides the beaks partly digested squid gladii, spermatophores and 15 specimens of the fish parasite Sphyrion lumpi (Crustacea: Copepoda) occurred in the stomach. No fish remains were found.

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Commercial fish species from the east Nigerian Coast were cxamined for extcrnal lesions and flcsh parasitic infections that may affect thcir consumahility. Altogether, 2 886 specimens from 43 species representing 34 genera werc sampled. The occurrence of lymphocystis disease in the pleuronectiform Cynoglossus senegalensis is here rcported for thc first time from an African marinc teleost. Other external lesions of fishcs cncountered were fin rot, granulomas, pseudotumours and ulcers with total prevalences not exceeding 1 %. The following commercial fish spccics were infectcd by muscle parasites at thc given prevalcnces: Cynoglossus brouni (mctaccrcariae, 18%, Capilluriu b pino osa cggs, 27%; Echinocephalus sinensis L3 larvae, 9%; Philomerru beninensis, 27%); C. senegulensis (Kudou sp., 10%; metacercariac, 87%); Pseudotolirhus bruchygnuthus (Hysterothylucium sp. larvae, 2%); P. srnegulensis (Poeciluncistrum cf caryophyllum plerocercoid, 1 %; Philometru beninensis, 1 %); P. typus (Kudou sp., 3%); Synapturu cadenati (Echinocephalus sinensis, 12%); Stromuteus jÏutola (trypanorhynch plcrocercoid, 44%); Epinephelus aeneus (didymozoid trematode, 44%; Hy~terothyluciunz sp. larvae, 6%). Cupillrrria and Echinocephalus, representing helminths with zoonotic potential, present low risks to public health due to their low prcvalences and the local methods of preparing fish for consumption. Apart from C. spinosa eggs in soles and trypanorhynch plerocercoids in S. fiutola, none of the other flcsh parasites are likely to affect the market value of thcir hosts at the rccorded levels of occurrence. Carcharhinid sharks influence the occurrence in the locality of most flesh-parasitic helminths for which they serve as definitive hosts. The absence of the third stage larvae of zoonotic Anisakidac 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 whcre similar studics have been earried out, the present study shows remarkably low prevalences and diversity for external lesions and flesh parasites in West African marine fishes.

Occurrence of stomach wall granulomas in European smelt was studled at 6 locations along the German North Sea coast. Identification of larval nematodes inhabiting these granulomas is provided for the first time. Three species, isolated by pepsin-HC1 digestion, are involved: Hysterothylacium cf. cornutum, Cosmocephalus obvelatus and Paracuaria tridentata. 7 2 % of all stomachs examined were affected. The ratio of number of granulomas to number of the 3 larval species free in the mesentery was 1:1.3. Differences in prevalences and intensities were significant among all locations. Granuloma abundance was highest in samples from the Elbe estuary decreasing in the other locations relative to their distance from the Elbe. There was no relationship between the number of larvae encapsulated on the stomach wall and the number of larval P decipjens in the musculature (r = 0.3).