Conservationists have called for an outright ban on shooting common seals in the UK after scientists discovered their numbers have fallen by more than a third in the past decade.
The Sea Mammal Research Unit (SMRU), which carried out a helicopter survey of moulting seals last week, said Shetland's population of common seals has dropped from more than 6,000 in 1997 to fewer than 4,000.
Campaigners said the figures demonstrated the need to reintroduce a year-round ban on shooting common seals in Shetland. It was scrapped in 1998 by the Labour government.
The islands' fish farming and fishing industry vehemently denied responsibility for the drop in numbers, though evidence of seal traps being deliberately set around fish cages has been uncovered in the past two years.
Scottish Natural Heritage described the figures as "pretty alarming" and called for surveys to be stepped up to discover if they were "a trend or a blip".
The shooting of common seals was banned in the Shetland Isles in 1973 after numbers fell to 1,750 owing to hunting for seal pelts. Afterwards, the SMRU's five-yearly surveys showed an increase until the population appeared to stabilise in 1996 at around 6,000.
In April 1998, amid protests from animal welfare groups, the Government lifted the special protection for Shetland seals. Shooting common seals is still outlawed during the summer pupping season.
Callan Duck, the leader of the SMRU survey team, said last week that since the ban had been lifted there had been a steady decline. "In 2001, we counted just under 5,000 common seals here. I doubt that we will get to 4,000 this year," he said. "What the reasons are for [the drop], we really don't know."
The Seal Preservation Action Group called for the Government to bring back the ban on shooting seals immediately. Its chairman, Andy Ottaway, said killing seals was against European law and posed a threat to tourism and fish sales. "Norwegian interests own most salmon farms in Shetland, and Norway has an appalling reputation for seal slaughter," he said. "This alarming decline in common seals demonstrates just how vulnerable our seal populations are."
David Sandison of Shetland Aquaculture, a trade association, rebutted claims that fish farmers were to blame. "I would absolutely deny that the industry was targeting seals. I am not saying that seals and salmon farmers are the best of friends, but I am saying that we co-exist and we do so very well."
A wildlife tour operator, Jonathan Wills, claimed there was strong evidence to link salmon farming with the fall in common seals. "It's well known that there have been illegal traps set. I know people who have seen spent cartridges on the beach, and I have seen a seal with a .22 bullet in its head."
Shetland Islands Council issues licences to fish farmers and is responsible for making sure they are not breaking the conditions of licences, which say predators should be "dissuaded or deterred" rather than killed.
SIC coastal zone manager Martin Holmes was not prepared to point the finger at fish farms without more evidence. "We really don't know what's going on," he said, adding that the council would "throw the book" at any fish farmer breaking the rules on harming seals.
The Shetland Fishermen's Association's chief executive, Hansen Black, said:"In the last few years there's been a shortage of fish in inshore grounds. Maybe that has contributed to the lower number of seals. But I would have no argument with a year-round ban on shooting seals."Reuse content