Description: In April 1990, 488 marine fish, belonging to 30 species from central Philippine waters, were investigated macroscopically for the occurrence of parasites in their flesh and for anisakid nematodes in their body cavity. Twenty-four fish were found to be infected by 1 of 4 different types of parasites. Unidentified Microspora were found in 4 host species from different families. Plerocercoids of the trypanorhynchid cestode Otobothrium penetrans occurred in the flesh of hemirhamphids and belonids only. Adult nematodes of the genus Philometra were found in the garfish Tylosurus crocodilus. The only parasite found which might be transferable to warm-blooded animals was the L-III stage of Anisakis sp. from the body cavity and the muscle of Muraenesox cinereus. The risk of human infections by parasites through consumption of raw marine fish in the central Philippines therefore is considered to be low.

Description: 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. 72% 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). Host condition factor could not be related to number of granulomas. Smelt appaears to be an important transmitter of spiruroid nematode larvae to marine birds in this region.

Description: In the tidal Elbe River between Hamburg and the estuary an assessment of fish stocks and fish diseases had been carried out in 1981-1986. Despite the decline of local fisheries, the river today still carries a rich fish fauna. Smelt and shad together contribute to 70 % of the fish biomass of anchor net catches. The remaining fishery today is sustained by eel catches. In the early 1980s, 70 % of the yearly income was from the sale of consumable eel, another 20 % from stock eel. Marketing of Elbe eel for human consumption, however, is forbidden due to high levels of toxicants in the fish. A rough comparison with anchor net catches from the end of the last century does not indicate serious changes in the frequency of the dominating fish species, except for a significant decrease in ruffe and a significant increase in pikeperch. The reduced fishing mortality today is partly compensated by power plants, which together with the cooling water take considerable amounts of fish out of the river. Recent surveys revealed a !arge variety of disease types and highly pathogenic parasites, some of which occur at very high prevalences. An ecological evaluation of this finding at present is not possible due to lacking data from other streams. High disease prevalences and low nutritional condition of flounder in the central estuary are attributed to naturally fluctuating salinities, which prevent the establishment of larger zoobenthos communities which could serve as fish food. The most serious problem for fish is seen in oxygen depletion which is observed regularly every year. However, the majority of fish emigrates from the Iow oxygen zone into shallow side arms and tributary rivers or assembles downstream in front of the low oxygen zone. Efficient rehabilitation measures are seen in a reduction of discharge of fertilizing substances into the river and in a re-opening or new construction of larger side arms.

Description: An association of Argonauta argo Linnaeus 1758 with Phyllorhiza punctata von Lendenfeld 1884 was observed in situ and collected north of Bohol Island in the Philippine archipelago. The argonaut held the exumbrella of the live lellyfish with its lateral and ventral arms. About half of the medusa bell surface was damaged and large pieces of mesogloea were lacking. The affected exumbrella area was charactenzed by the presence of masses of rod-like bacteria which did not occur on the undamaged ciliated surface. The center of the bell showed 2 holes interpretated as bite marks from the cephalopod. Five channels led from the holes to the medusa's gastric cavity. This connection possibly enabled the argonaut to feed on the tissue and to access particles caught by the secondary mouth papillae of the oral arms of P. punctata. Furthermore, the association could serve A. argo as protection or camouflage against predators because of the stinging capability of the scyphomedusa.