Otters

The otter, also known in Northwest Scotland by its Gaelic name Dobhran and Beaste Dubh (black beast), belongs to the same family as badgers, weasels, stoats, pine marten and mink. 

Scotland is a European stronghold for the otter and it now occurs over the whole of the country. When pesticide pollution of waterways eliminated otters from most of England and Wales, they survived in Scotland's cleanest water bodies in the north and west. Now the population has recovered, otters can easily be seen in many areas, but particularly on the west coast and the islands. In 2003, the total Scottish population was estimated at around 8,000.

Otters are largely solitary, semi-aquatic mammals that obtain most of their food from lochs, rivers or the sea. The Scottish population is unusual in that it comprises a particularly high proportion (perhaps 50% or more) of coastal-dwelling individuals that feed almost exclusively in the sea. Nowhere else in the British Isles are coastal habitats more important for this species than the coast and islands of western Scotland and Shetland; so much so that coastal otters are occasionally referred to as 'sea otters' despite the fact that they are exactly the same species as the animals which inhabit freshwaters further inland.

In freshwaters, otters feed mainly on fish such as trout, salmon and eels, but in the spring spawning frogs and toads become important prey. Mammals and birds are also taken occasionally.  In these habitats, otters are largely (but not exclusively) nocturnal and occupy very large home ranges (around 32 km for males and 20 km for females).  In contrast, their coastal counterparts are mainly active during the day and, because these productive inshore waters provide so much fish and crustacean prey, they need much smaller home ranges - as little as 4-5km of coastline. Coastal dwelling otters require a ready supply of fresh water to wash the salt out of their fur, which would otherwise rapidly lose its insulative properties.

The principal issues affecting Scotland's internationally important otter population are: road kills and other unnatural mortality. Road casualties are considered to be the single biggest source of non-natural mortality. Commercial eel fishing and 'creeling' for crustaceans has also been identified as a threat in some areas. As a consequence, protective otter guards were developed for use with eel fyke nets, dramatically reducing otter drownings. Otter predation on stillwater fisheries (and occasionally also on domestic ducks and poultry) can sometimes be a serious problem for the owners and managers concerned. The solution usually lies with appropriate stock protection measures and guidance is available on protective fencing from the Specialist Anglers' Alliance and in Otters and stillwater fisheries. 

Despite these threats, the Scottish otter population is flourishing and in most parts of the country, there no evidence to suggest that they are having a detrimental effect on the overall population. Nevertheless, Scottish Natural Heritage continues to work closely with developers and road engineers to ensure that the appropriate mitigation measures are put in place on new road schemes to avoid casualties.  Wherever possible such measures should also be retro-fitted at known black-spots on the existing network.