Editorial

In this issue of the Journal of Helminthology I have much pleasure in including a selection of papers drawn from two workshops, one on 'Nematode Population Genetics' and another on the 'Ecology of Fish Parasites' held in April 1998 at Exeter during the Spring Meeting of the British Society for Parasitology (BSP).The aim of the workshop on 'Nematode Population Genetics' convened by Dr Mark Viney, University of Edinburgh, is to review the current state of knowledge of this topic and to consider future research priorities. Following Mark Viney's overview, Michael Blouin, Oregon State University, Corvallis, USA, considers the effects of parasite life histories on mitochondrial DNA diversity in nematodes. Marleen Roos et al., Institute for Animal Science and Health and the University of Utrecht, The Netherlands, then review polymorphic DNA markers in the genome of parasitic nematodes whereas in the fourth and final paper of this series Alison Galvani and Sunetra Gupta, University of Oxford, consider the effects of mating probability on the population genetics of nematodes.Two papers from the workshop on the 'Ecology of Fish Parasites', convened by Professor Clive Kennedy, University of Exeter, focus on the community ecology of helminths in fish and include a study by Clive Kennedy et al., University of Exeter and University of Rome on the 'Composition and diversity of helminth communities in eels in the River Tiber: long term changes and comparison with insular Europe'. This is followed by an invited paper by William Font, Southeastern Louisiana University, USA on 'Parasites in paradise: patterns of helminth distribution in Hawaiian stream fishes'.I wish to express my grateful thanks to Mark Viney and Clive Kennedy for their assistance in the publication of these papers for this special issue.