(Convener: Knights; Rapporteur: Scott)
36. Hoglund described an ELISA immune response technique for assessing prior exposure of eels to the Anguillicola crassus nematode infections. Careful purification of antigens is necessary but the technique represents a valuable research tool.
37. Papers on A. crassus infections in German coastal waters and Danish inland waters were presented by Hahlbeck and Boetius respectively. These showed variable levels of infection, reaching 100% in some eel populations from both areas. High rates were not clearly related to body condition. Some decline in rates has been shown in Danish waters but also some new sites of infection. Swim bladder damage has been demonstrated. The papers and ensuing discussion expressed concern about effects of the parasite on eel stocks and oceanic migration but conclusive evidence is still lacking.
38. Callaghan & McCarthy presented information on metazoan parasites of eels in the Dunkellin catchment in the west of Ireland. The parasite fauna was relatively diverse, though assemblages were typically dominated by one or a few species. These tended to correlate with eel diet and biology and the presence of appropriate intermediate or definitive hosts.
39. Knights gave a review of known work on eel hydrocarbon and heavy metal contamination for 1991–3, as requested at the 1991 Meeting. Fourteen papers and four programmes/surveys were covered. Further integrated work on the use of eels as indicators, on kinetics and bioaccumulation and on body burdens is needed. Clarification of biotransfer of accumulable pollutants from eels to higher trophic levels (especially to humans) and possible effects on eel migration and breeding success should have high priority.
40. Tulonen described contamination of Finnish eels by radionuclides following the Chernobyl accident in 1986. Levels of Cs134 and Cs137 increased for several years before a reduction in levels was observed. Mosaic patterns of contamination occurred, as is the case for other countries affected by the accident. Predatory species such as perch and pike had accumulated much higher levels than eels. Reductions in consumption of fish had been recommended by the government but the situation now appears to be improving, despite the long half lives of caesium radionuclides.
41. A poster by Purcell and McCarthy illustrated the life cycle, prevalence and distribution of the copepod gill parasite Ergasilus gibbus in certain Irish lakes.
42. A paper by Lara was circulated giving an account of glass eel fishing in Asturias in northwestern Spain from 1952 to 1992. Catches were relatively low from 1952 to 1972, increased sharply in the 1970s and declined again in the 1980s.
