Following the decline of the European Otter, Lutra lutra, throughout much of Western Europe during the twentieth century, Otter populations have been regularly monitored in the UK. National surveys have been carried out since the 1970's, approximately every seven years, in England, Wales, Ireland and Scotland. The same sites have been surveyed using the same techniques. The surveys have been organised and funded by a variety of groups including the Vincent Wildlife Trust, English Nature, Scottish Natural Heritage, the Countryside Council for Wales and the Environment Agency.

The latest survey results, published April 2004, come from the fourth National Otter Survey in Wales for 2002. The survey shows a marked increase in the number of places that Otters are found, exceeding the targets set out in the UK Biodiversity Action Plan.

The survey methods used give an indication of whether otters are present or absent from particular sites, and do not assess changes in abundance. However, they are a good source of information of change in the UK Otter distribution pattern.

Of the 1097 sites surveyed, 71% had signs of Otter. 1008 of these sites are common to all previous surveys, and if only these sites are used for comparison, 74% of sites were found to have signs that Otters were present. This compares with 20% in 1977/8, 38% in 1984/5 and 53% in 1991. The overall percentage increase in positive records between 1991 and 2002 was 41%.

During the 1950's and 60's the Otter population suffered significant decline throughout Europe, following widespread increase in use of pesticides and higher levels of habitat pollution. In the 1970's the UK's Otter population had been reduced to scattered populations in mid and west Wales, the West Country, Scotland and Northern Ireland. The presence of Otters is an important indicator of the health of our rivers and wetlands. Improved water quality, increased fish stocks and changes in river management have all played a part in providing a better habitat for Otters.

Dr Madeleine Harvard, Director of Operations for The Wildlife Trust of South and West Wales, said: "The success story of the Otter in Wales is a clear indication of what can be achieved by working hard in partnership with others. But we must not be complacent - even on our most successful rivers. The Welsh Wildlife Trusts are determined to see that Otter numbers continue to grow. We can all help to achieved this if we keep working closely with landowners, industries and developers - to bring about an improvement in water quality and to ensure that no more vital habitat is lost alongside our rivers."