There has been a large rise in the number of otter deaths on Shetland’s roads this year, with as much as 10 per cent of the population killed, according to alarming figures published by Scottish Natural Heritage yesterday.
Normally around 13 dead otters are received by the conservation body’s office in the isles, but this year 21 have been handed in. However, many more are likely to have been killed since not all casualties are reported, according to area officer Glen Tyler.
Motorists are being asked to keep a watchful eye out for the iconic mammals as they drive around this winter.
Mr Tyler said: “Given the increase in deaths this year we’re asking drivers to be aware of the locations where otters may be encountered such as coastal roads and places where roads cross water courses. We ask that extra care is taken at these sites, especially during the dark winter nights.”
It is thought that around 60 per cent of the total of dead otters found die in violent circumstances, although road deaths seem more prominent as the animals are easily found. More may die in dens, for example, and are never found.
It is thought this is increasingly due to a recent lack of food and animals subsequently travelling further to forage.
“Most otter road deaths happen from October to December and usually coincide with darkness around rush-hour involving young otters seeking new territories. These energetic mammals often dart across roads near water and sadly many are killed each winter in road accidents as motorists are taken by surprise by their sudden appearance,” said Mr Tyler.
“Unfortunately the strong legal protection afforded by the habitats regulations, while saving them from deliberate harm and disturbance, does not prevent their accidental death on the road.”
SNH routinely collects carcasses of dead otters and sends them to the University of Glasgow Vet School for autopsy. With a population of perhaps around 500 adults this year’s death toll may approach 10 per cent of the population.
Since 1981, SNH has received 392 corpses of otters, mainly road casualties. Ironically, autopsy examination is a very good way of measuring “health” of the population as it provides information on age, sex and breeding status of animals as well as data on pollutants and cause of death.
The otter population in Shetland is monitored by the renowned otter specialist Jim Conroy at a sample of sites in northern Shetland. The study has lasted for more than 30 years and for much of that time has been supported by oil firm BP.
The observed trend from those sample areas is that the population declined from an estimated peak of 1,000 otters in Shetland in the 1980s and early 90s to a low point in the mid-1990s.
By 2001 numbers had recovered close to the peak of the previous decade but the most recent surveys suggest there has been a significant population decline of more than 50 per cent from 2003 with no sign of a recovery since then.
Mr Conroy said the evidence suggests that a lack of food is the most important factor in the decline.
He said: “The decline in otter numbers is most likely caused by a significant reduction in the availability of the animals’ main prey, small inshore fish.
“This has been reflected by an increase in the amount of crab in the diet immediately before and during the decline periods.”
Shetland’s otter population is of national and international importance. At one time, it was the most densely populated area for otters in western Europe.
“Despite the fall in otter numbers, Shetland still has a high density of otters, and the chances for people to view them are as good in Shetland as anywhere.”
SNH would like motorists to take particular care in known otter areas, such as the north Mainland and Yell as well as spots in the South Mainland.
They would also like to know if you see any dead otters in Shetland. The local area office can be contacted on (01595) 693345, or by email at Northern_Isles@snh.gov.uk