After a year in general practice he became a member of staff of the
Glasgow Veterinary School. While training as a general comparative pathologist, including spells in the Medical School of the University, he commenced his work on the pathogenesis of disease in teleost fish. He also began a major programme of clinical diagnostic work for the new salmon, trout and turbot farming industries which were developing at the time and in 1971 the Nuffield Foundation awarded him a major Research Programme Grant to develop the role of veterinary medicine in this developing field. Space constraints at Glasgow led to the transfer of the programme to the
University of Stirling, nearby, under the guidance of an Academic Advisory Committee chaired by Sir William Weipers, Dean of the Glasgow School. Here the world's first Master's degree training courses in Aquatic Veterinary Studies were created. Over the next 25 years a pioneering international reputation was established in relation to tropical and temperate aquaculture such that the Institute of Aquaculture at Stirling became the largest such Institute in the world. Between 1982 and 1985 Roberts was seconded to the UN to lead an International Mission to investigate a pandemic of a lethal disease in wild and rice field fishes. The condition was widely believed to be associated with the new technologies for production of the short straw rice varieties which had transformed food supply in much of Asia. It was demonstrated conclusively, however, that pesticide usage was not a factor and the condition was due to a new mutant aquatic fungus,
Aphanomyces invadans. Roberts was nominated for both the Japan Prize and the King Baodouin Prize for this work. He was also invested Commander of the Order of the Crown of Thailand (CCT) by HM King Bhumibol Adulyadej of Thailand. In 1978 he was elected Fellow of the Royal Society of Edinburgh. His proposers were Professor RMS Smellie, Sir William Weipers, Sir Cyril Lucas and Sir William MacGregor Henderson. He served as a member of the World Bank Review of Agricultural Research in India in 1989, a member of the OECD Review of Biotechnology Agriculture and Food in 1992; and a member of the Cabinet Office Agricultural Scientific Restructuring Committee in 1991. On retirement to Kintyre, on health grounds in 1996, he completed the fourth edition of his standard text
Fish Pathology. He remained involved in fish disease research with the
University of Idaho;
Roslin Institute and commercial companies. He also served on Committees of the
European Food Safety Authority and the
Scottish University Funding Council. In 2000 he collaborated with Sir
Paul McCartney and a few of his friends in the establishment of a Memorial Garden to Lady Linda McCartney in Campbeltown and was closely involved in local charities. He also planted 200,000 native hardwood trees on his family land in
Argyll in an attempt to offset his career international flight CO
2 deficit. == Awards and honours ==