Current statusThe otter was formerly widespread throughout the UK and Europe but underwent a rapid decline in numbers in the1950s and 60s probably due to pollution from farm pesticides and habitat loss. By the late 1970s the otter was almost extinct in the UK apart from a few strongholds in Scotland such as Dumfries and Galloway and the Highlands and Islands. However, by the 1980s otter populations had begun to recover due to the phasing out and banning of some hydrocarbon pesticides. In North Lanarkshire the otter is widespread and thought to be increasing its range as the water quality of our rivers and burns improves. The otter population in Scotland is seen as one of the strongest in the UK, but is identified in the biodiversity steering group report as needing conservation action.
Legal protection
The otter is listed on Appendix I of CITES, Appendix II of the Bern Convention and Annexes II & IV of the Habitats Directive. It is also protected under Schedule 5 of the Wildlife and Countryside Act 1981 and Schedule 2 of the Conservation (Natural Habitats etc.) Regulations, 1994.
This protection means that it is an offence to deliberately:-
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Kill or injure otters
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Capture or keep otters
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Destroy, damage or obstruct their den
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Disturb them while in the den
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Sell or advertise for sale, otters and anything derived from them, import or export otters, whether dead or alive
The above actions can only be carried out with a specially granted licence, issued by SNH.
Ecology and management
Otters are shy, semi-aquatic, mostly nocturnal creatures (although they can be diurnal where they suffer little disturbance) and are, therefore, very rarely observed. Their fur is generally medium to dark brown in colour with a pale underbelly. Their adult size varies from 1-1.2m, 6-8kg, females are generally smaller than males.
They are found in almost all wetland habitats including lochs, rivers, burns, ditches, reedbeds, marshes, estuaries and the coast. They are especially common on the west coast of Scotland where they are not so nocturnal. Within these areas an otter will need up to 30 holts (dens) or lying up sites in their home range. Large cavities in bankside tree roots, dense impenetrable scrub, rock cavities, peat burrows and old culverts are all examples of typical holt sites. One of the best ways to identify a possible holt is to look for their droppings known as spraints which are black and spiky and have fish bones in them. Footprints and runs are also good indicators of an otter's presence.
Their main diet is fish, with eels being a favourite, although they will eat amphibians (frogs are an important food source in spring), small mammals and some birds. An adult otter requires about 1kg of food a day. This high value is due to the amount of energy used hunting their aquatic prey.
Breeding is non-seasonal, therefore they can breed at any time of the year. The female gives birth to one to four cubs in the safest holt in her home range. The cubs remain there for about two months and then begin exploring their territory with their mother. They will stay with her for 12 to 18 months before finding their own territory (the father plays no role in rearing the cubs). They are sexually mature at two years but life expectancy is short, three years on average, although their potential life expectancy is up to fifteen years, late sexual maturity, small litter size and a short life expectancy make breeding success critical.
Otters require clean rivers with a plentiful supply of food and bankside vegetation.
Limiting factors
Pollution is thought to have been the main cause of the otter's population decline in the 1950s and 60s. The main sources of pollution were, and still are, industrial and agricultural waste. PCBs (Polychlorinated biphenyls) are thought to be a particular problem as is increasing acidification of watercourses due to acid rain and leachate from conifer plantations. PCBs are toxic and can accumulate through the food chain while acidification can cause a reduction in food availability.
Habitat loss and disturbance were also a major factor in the otter's decline in numbers although more and more organisations are promoting the sympathetic management of watercourses for a variety of wildlife. Disturbance is still a major factor as waterways are increasingly used for recreation; boat traffic, people and dogs cause major problems in some places.
Road deaths, drowning in nets used for eels and accidental snaring are other factors.
Current action
The Vincent Wildlife Trust carried out three otter surveys in Scotland the latest one in 1994 but have no plans for a fourth at the moment.
SNH recognises the need for a systematic survey and study of the otter population in the North Lanarkshire but little resources are available as yet.
The JNCC has prepared a Framework for Otter Conservation in the UK 1995-2000.
Research is in progress on the implications of heavy metal and PCB contamination in fish and ecosystems.
Main objectives
Objective 1: Maintain the otter population in North Lanarkshire at its current level.
Target: Ensure no net loss.
Objective 2: Reduce road mortality in the region
Target: Reduce road mortality by 40% by 2005
Objective 3: Promote education and awareness of the status and requirements of otters especially amongst groups that have an adverse effect on them and promote coordination among those working on otter conservation.
Target: Set up a Lanarkshire Mammal Group.
Action
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