Lutra lutra L.1758
Family: Mustelidae

Northern Ireland has a healthy population of otters at present. However, a recent survey suggests that there has been a slight decrease in signs of otter activity over the last 20 years.

Otters are good indicators of water quality — they need clean, unpolluted water with a large and varied supply of food. Dense, undisturbed areas of bankside vegetation are also essential to provide cover when the animal is resting during the day and for breeding purposes.

In brief

• Found throughout Northern Ireland in suitable habitat
• Prefers unpolluted rivers/lakeland and coastal habitat
• Active all year round, and are mainly nocturnal
• Listed as a UK Priority species
• Main threats to the population are water pollution, loss of habitat and accidental capture in fishing nets and traps.

Species description
The otter has a long streamlined body with very short legs, webbed feet and a thick, muscular tail. The head is broad and flattened with small eyes and ears. When swimming underwater, the otter can close its nostrils and ears.

The fur is dark brown and made up of two layers: the long shiny guard hairs that form the waterproof outer coat and the soft thick under-fur that keeps the otter’s body warm.

Life cycle
Otters are shy, solitary animals that are active mainly at night. They are always found near freshwater — in coastal areas the otter must have access to freshwater to wash seawater from their coats otherwise the fur becomes clogged with salt crystals and loses its ability to keep the otter warm. Cubs (up to four) are usually born during the summer months in an underground den or holt and stay with their mothers for about a year. Otters can live for up to 10 years and feed mainly on fish, frogs and crayfish, though other prey such as small birds may be taken.

Similar species
The only animal that might be easily confused with an otter is the American mink — when compared with a domestic cat, a mink is smaller and an otter is much bigger (length including tail 92-110cm). Mink also tend to be darker — appearing almost black, especially when wet.

How to see this species
The Fermanagh lakes and the rivers associated with Lough Foyle are good areas to look for otters. Otters are very hard to see since they are mainly nocturnal — they do however leave signs of their presence —droppings (spraints) are left in prominent locations — on rocks, logs etc. to mark their territory. Spraints often contain fish scales and bones and have a musky smell.

Current status
The otter occurs throughout Northern Ireland in freshwater and coastal habitats. The actual number of otters present is not known but a recent survey recorded signs of otter presence in 65 per cent of sites surveyed. Otter populations in Europe declined rapidly from the 1950s onward and by the mid-1970s the otter was seriously endangered in many countries. The decline was due mainly to pesticide use, water pollution, destruction of habitat and hunting. The otter population in Northern Ireland did not suffer this serious decline and continues to remain in a healthy state.

• Protected at all times in Northern Ireland by Schedule 5 of the Wildlife (N. Ireland) Order 1985. Also listed on Schedules 6 and 7
• Listed in Annex II and IV of the EC Habitats Directive
• Listed in Annex II of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention)
• Classified as Near Threatened on the IUCN Red List 2004
• Listed under CITES Appendix 1 (4).

Why is this species a priority in Northern Ireland?

• Listed as a UK Priority species.

Threats/Causes of decline

• Pollution

• Farm waste
• Pesticides
• Oil spills in coastal areas

• Habitat loss

  • Removal of bankside vegetation
  • Draining of wetlands

• Accidental death

  • Drowning in fishing equipment
  • Road traffic injuries

Conservation of this species

Current action
There is a UK Species Action Plan for this species which was published in 1995.

• In 2001, EHS commissioned a survey of otter distribution in Northern Ireland. The results of the survey show a decline of nearly 10 per cent in signs of otter occurrence throughout its range. The report was published in 2004 (link below)
• Implementation of the Northern Ireland habitat action plans for Mesotrophic Lakes, Eutrophic Standing Waters and Marl Lakes.

Proposed objectives/actions

• Maintain existing viable otter populations
• Expand existing viable otter populations
• By 2010, restore breeding otters to all catchments and coastal areas where they have been recorded since 1960.

What you can do
To report otter sightings contact CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU, Tel: 028 9039 5264, cedar.info [at] nmni.com

Further information

Links
UK Species Action Plan for Otter

Reassessing Otter Lutra lutra distribution in Northern Ireland

Common otter- ARKive

Northern Ireland Habitat Action Plans

Literature

Text written by:
Angela Ross, Curator of Vertebrates, Ulster Museum

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