Health – Introduction
diagnosis I
Good
Transformation of aquaculture has been made possible by advances in control of ‘new’ diseases
t’s now exactly 50 years since I fi rst started to work on fi sh pathology. In 1965 there was a spate of diseased wild salmon presented for diagnosis at the University of Glasgow Vet School. No one knew anything about them, so as the most junior pathologist, I was assigned the task of
post-morteming them and reporti ng to the aggrieved river proprietors. That was the start of the UDN outbreak which lasted only for a few years
but changed the way we deal with fi sh diseases in the UK forever. It led directly to the setti ng up of the fi sh disease teams in Aberdeen and Wey- mouth, and also to my being given the chance to set up the fore-runner of the Insti tute of Aquaculture, the Aquati c Pathobiology Unit, funded by the Nuffi eld Foundati on. Over the ensuing half a century, the world of aquaculture has been trans-
formed from a minor contributor to human nutriti on to, in the case of both Scotland and Norway, for example, the largest food producing industry, and worth far more than the value of catt le and sheep producti on combined. None of this would have been possible without the contributi on of the
scienti sts and veterinarians who have discovered, diagnosed and controlled the plethora of ‘new’ diseases that have arisen in the course of develop- ment of intensive salmonid and shrimp producti on and, further afi eld, in the great contributi on that tropical aquaculture is now making to feeding the developing world. The situati on is not now all rosy, however. Vaccines have made great con-
tributi ons to the viability of many producti on systems, resulti ng in minimal use of anti bioti cs nowadays. Bett er understanding of biosecurity and also internati onal movement regulati ons have limited the risk of viral epidemics such as the ISA outbreaks that virtually destroyed the Chilean industry. But parasites, especially the copepods, conti nue to present a challenge
in many areas. New work on vaccines even for these is starti ng to look promising but it will be a long haul I fear. One area which has been parti cularly exciti ng, though, has been the pros-
pect of geneti c selecti on for disease resistance. The work on development of salmon resistant to IPN which our Landcatch team did with the Roslin Insti tute was recently stated by a very senior scienti st at an internati onal animal breeding conference to be ‘
....generally regarded as possibly the most successful example of geneti c control of disease resistance in any livestock species’. Praise indeed. The success of these techniques provides hope for many of the other se-
rious pathogens. Just before I fi nally reti red last year, we were able to an- nounce, in conjuncti on with a consorti um of Scotti sh universiti es, that work we were carrying out at the Machrihanish Marine Laboratory was showing that it was possible to produce geneti c resistance to sea lice as well! In many ways that is the Holy Grail of fi sh pathology, with implicati ons for
other parasiti c diseases and other fi sh species as well. The scienti fi c papers are now published and the commercial exploitati on is beginning both in Scotland and Norway. While there will sti ll be a role for the wrasse and the
16
Above: There is lots of hope for the welfare of fi sh
lice treatments, for some ti me to come, I am sure lice control will become much easier and such treatments will be much less frequent in the near future, to the benefi t of all concerned. So the future is bright for the industry and I
believe also glowing for the fi sh veterinarians and their scienti fi c colleagues. There is now a large World Aquati c Veterinary Medicine Associati on (WAVMA). In Scotland, in Norway and indeed throughout Europe, there are signifi cant groups of scienti sts working on previously intractable problems. When we add this to the large eff ort in the Americas, Asia and of course Australasia, the diff erence from 50 years ago, when we were, I guess, less than ten veterinarians in the whole world working on fi sh, is stark. As the following pages will demonstrate, there
are sti ll diffi cult problems, but also lots of hope both for the welfare of the fi sh and the environ- ment and for the fi nancial benefi ts that result, oft en in economically challenged regions, from adequate management of diseases in fi sh stocks.
Professor Roberts headed the Nuffi eld research unit, later the Insti tute of Aquaculture. His book Fish Pathology, fi rst published in 1978, is now in its fourth editi on and has been translated into ten languages. He was a director of Landcatch, and visiti ng professor at Idaho University, edited the Journal of Fish Diseases, and contributed to the fi rst editi ons of Fish Farmer and the Fish Vet’s Diary in Fish Farming Internati onal. FF
www.fishfarmer-magazine.com
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