Threatened Otters Return to British Waterways

LONDON, UK, January 24, 2007 (ENS) - New recovery targets for the UK’s threatened otter populations have been set by the government following confirmation that the species has been sighted in every major British city.

The aquatic mammals are returning to rivers where they have not been seen for decades. Last year, otters were discovered in central London for the first time in over a century.

By 2010, the British government has pledged to restore breeding otters to all the areas where they were recorded prior to the 1960s - river banks, lakes and coastal areas. This target is in the government's Biodiversity Steering Group Report, which includes the otter.

The otter, Lutra lutra, is on the road to recovery in Britain. (Photo courtesy WWF-UK)

A new Biodiversity Action Plan target issued by the government aims to return the aquatic mammal to 85 percent of its former river habitat by 2015.

Biodiversity Action Plans are targeted actions to protect and enhance 391 species and 45 habitats that are under threat in the UK, including otters.

While otter monitoring studies are conducted every seven years, the Environment Agency gives no current otter population figures.

The agency does say that the most promising improvement in otter populations has been in England where otters are now found in almost twice as many areas as they were 10 years ago.

"In the late 1970s our initial goal was to consolidate numbers and stop the otter population from further losses. At this time only six percent of traditional sites in England had evidence of otters," said Scholey. But with water quality and habitat improvements, scientific surveys have shown that otters have returned to at least 75 percent of the territory that once formed their traditional range.

"This doesn’t mean these rivers have established viable long-term populations," he said. "In some cases it may only be one or two otters moving back into an area where their ancestors had previously flourished. But it’s a good sign."

The otter is listed on Appendix I of the Convention on International Trade in Endangered Species, which means they cannot be traded. They are protected under the Convention on the Conservation of European Wildlife and Natural Habitats, known as the Bern Convention, and also under the European Union's Habitats Directive.

When otter populations were at their lowest in the 1960s and '70s, the Tryweryn catchment in Snowdonia National Park was one of their last strongholds in Wales. (Photo courtesy Environment Agency)

The conservation group WWF-UK and partner organizations are helping to maintain and expand existing otter populations.

WWF and the Worcestershire Wildlife Trust are working together on a section of the River Avon to provide a suitable habitat for otters moving through the district by recreating an historic wetland area.

WWF is also surveying parts of Cheshire and Essex for otters, and intends to monitor their movements in these counties.

There are proposals for two Special Areas of Conservation for otters and WWF is lobbying for more protected sites so that habitat suitable to otters and other aquatic animals can be maintained.

Scholey said, "Working with local wildlife trusts and water companies to improve water quality, riverbank habitats and wetlands has undoubtedly helped the otter populations to establish and grow."

"Although otter numbers in the rivers surrounding London and the Southeast are still low compared to some other parts of the country this is clear evidence that the population is breeding and spreading," he said.

Destruction of riverside habitat and hunting, followed by rapid industrialization in the 1950s nearly wiped out the otter which disappeared completely from much of England, Wales and southern Scotland.

At that time, increasing numbers of factories and residential development spewed organo-chlorine pesticides and polychlorinated biphenyls, PCBs, into the environment where they accumulated in the food chain, especially in the fatty tissues of eels, a favorite food of otters. Poisoned by the toxics, otters suffered damage to reproductive and immune systems, and numbers further declined.

A ban on some members of this class of pesticides has helped the recovery of otter populations.

Pesticide and PCB levels in fresh water food chains have declined steadily and WWF says, "There can be confidence in the otter's future if the threat of a resurgence of pollution is kept in mind and curbed."

Today many otters are killed crossing roads especially in lowland river areas where they have reappeared. WWF recommends that bridges be built with otter corridors to improve the animals' road safety.

"We now need to accurately monitor their fortunes and health into the future and deal with any threats, such as road kills," said Scholey. "As top predator, the otter is one the most valuable indicators of a healthy water environment, and achievement of these targets will be testimony to the continued improvement in the state of our rivers."