It is a tribute to the vigour of research and development in aquaculture that we are able, in a relatively short time, to provide readers with a second volume in this series, which has such a diversity of high calibre research and developments to report. That the first volume was so well received has been a source of great satisfaction to the editors and supported their conviction as to the need for links to join the research laboratory to the fish farm by making current research available to a wider range of potential users.