Pete Bevington

19 April, 2007

AN OTTER specialist in Aberdeen has disputed the findings of a survey which suggests the creature has multiplied in Scotland over the past 40 years.

Consultant Jim Conroy said his studies in Shetland showed a 40 per cent decline in otter numbers over the past three years, due in his opinion to a shortage of food. Similar declines have been recorded in Skye.

Yesterday it was announced that a Scottish Natural Heritage survey showed otters had started to appear in areas of Scotland where they had not been seen for years.

The SNH report suggested there were around 8,000 otters distributed across most of Scotland, including areas around Aberdeen and the River Clyde.

However Mr Conroy, who has been studying otters in Shetland since 1979, said he had seen a marked decline since 2004.

"SNH were looking at the distribution of the species, but in Shetland I am looking at numbers. It would be fair to say there has been a 40 per cent decline in Shetland, perhaps even greater, but it's hard to tell," Mr Conroy said yesterday.

He said the fall was probably related to similar population drops being observed in seal and sea bird colonies. Common seal numbers in the northern isles have plummeted by around 40 per cent in the past 10 years, and seabird populations have been decimated over the past decade.

"My gut feeling is that this is all to do with a shortage of food," Mr Conroy said. "Whenever we see otters feeding on crabs we see a decline in numbers, and we've seen a lot of that lately."

Crabs are one of the less nutritious meals enjoyed by otters, who have the added difficulty of bringing them ashore to eat. Inshore fish, such as rockling and butterfish provide more sustenance and can be eaten at sea.

Shetland's otter population stood at around 1,000 creatures in the early 1980s, but fell during the 1990s. In 2001 it was almost back up to earlier figures, but has fallen away again.

Mr Conroy is the chairman of the World Conservation Union's otter specialist group.