SLAUGHTER to control animal disease is becoming increasingly contentious.
Most attention is on foot-and-mouth disease, where more than a dozen inquiries are being held into an epidemic in which more than six million cattle, sheep and pigs have been slaughtered.
One of those inquiries is an independent one by the Royal Society of Edinburgh.
But the society is also carrying out an inquiry into a disease of farmed salmon, which raises similar questions about causes and methods of control or eradication.
Infectious salmon anaemia (ISA) is a viral disease which, like foot-and-mouth, poses no threat to human health.
The first case of ISA was found in 1998 in a Loch Nevis salmon farm and, to date, it has spread to 11 farms and has been suspected on a further 25 in Skye, Orkney, Shetland and the Western Isles.
Again like foot-and-mouth, infection by the virus does not necessarily produce severe clinical signs of the disease or death, but European legislation requires that, once a fish farm has been designated as infected, all fish must be slaughtered, the site disinfected and left fallow for six months.
However, unlike foot-and-mouth and a crucial difference for salmon farmers, there is no government compensation for lost stock.
Compensation payment claims from fish farmers have been resisted by the Scottish executive, and a decision is now awaited from the European Court of Justice.
Sir Roderick MacSween, the chairman of the Royal Society of Edinburgh working party, and emeritus professor of pathology at the University of Glasgow, said: "We wish to examine the evidence for ISA being an exotic and not an endemic infection in salmon in Scotland."
Sir William Stewart, president of the Royal Society of Edinburgh, said of the ISA inquiry: "This is a complex issue for environmentalist, business and local communities. Our inquiry must be focused on the science underpinning it and advice must be wholly independent and scientifically robust."
Brian Simpson, the chief executive of Scottish Quality Salmon, recently pointed out the "huge contribution" made to Scottish life and economy by farmed salmon: 6,500 jobs, 300 million of sales ex-farm generating 600-700 million retail sales - worth more than Highland beef and lamb combined and accounting for 40 per cent of all food exports.
The counter-argument is that the industry is causing environmental damage and that farming fish produces unexpected side-effects, such as ISA.
The Crown Estate is to provide a further 600,000 for research over three years to help fish farming to "achieve its environmental goals". Advice on its allocation will come from an industry-wide committee.
Scientists from the Fisheries Research Services and the University of Aberdeen have started a 1.4 million research project to find out if global warming is to blame for the disappearance of some fish from Scottish waters.
The first work is to survey declining stocks of the zooplankton species calanus finmarchicus - a vital food for fish like cod, herring and mackerel.
Professor Peter Boyle of Aber-deen University said: "The purpose of our expeditions is to discover more about how climate change is affecting the supply of food to fish in our seas - then we can have more confidence in predicting what the fisheries of the future will be like."