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 they now occur over the whole of the country. Pesticide pollution of waterways eliminated otters from most of England and Wales but they survived in Scotland's cleanest water bodies in the north and west. The population has recovered and 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 unusually comprises a particularly high proportion (perhaps 50% or more) of coastal-dwelling individuals that feed almost exclusively in the sea. The coast and islands of western Scotland are particularly important for this species and 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. 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. These can be 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.
Road kill and other mortalities caused by humans are the principal issues affecting Scotland's otter population. Road casualties are considered to be the single biggest source of non-natural mortality whilst 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. The solution usually lies with appropriate stock protection measures and guidance is available on protective fencing in Otters and stillwater fisheries .
Despite these threats, the Scottish otter population is flourishing in most parts of the country. 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.
Last updated on Friday 26th February 2016 at 15:15 PM. Click here to comment on this page