Otters have been found using waterways in some industrial areas of Wales for the first time in nearly 30 years.

Conservationists have revealed that there have been new sightings in more than 100 towns and cities across the UK where it was believed otters no longer lived.

Among the areas noted in the Wildlife Trust survey are Port Talbot, Merthyr Tydfil, Haverfordwest, and Cardiff.

Waters where the otter hunts are less polluted

Nigel Ajax-Lewis, conservation officer with the Wildlife Trust of South and West Wales, said that while otter numbers had been rising in some areas, until recently they had only been recorded on the edges of cities, or within a 10 or 20 mile radius of major urban areas.

"We have had sightings of otters climbing in and out of dustbins at supermarkets in towns, and others have been spotted near local authority offices in a town centre in south Wales, right next to a busy road," he said.

"One of the biggest contributing factors is the fact that our waterways are so much cleaner now, and that is largely because of the closure of the coal mines.

"Also, organisations like the Wildlife Trust have put a lot of resources into making sure that otters have places to breed by protecting habitat and by building artificial holts."

Dramatic comeback

Research released earlier this year revealed that otter numbers had risen generally across Wales - but the latest survey - carried out by conservationists working on the Wildlife Trust's Water for Wildlife project - is the first evidence that they are returning to more urban areas.

Otters have made a dramatic comeback in recent years after virtual extinction in the 1960s.

Their decline was linked to pollution, farm pesticides, and destruction of habitat.

The gradual return began with the phasing out of chlorinated hydrocarbon pesticides which, with other chemicals, built up in fish - the otter's main prey

In 1998, the government set a target of restoring otters to all UK rivers by 2010