Otters are an important indicator of the health of our rivers and monitoring the status of the otter population gives a valuable measure of the state of our water and wetland ecosystems. The Environment Agency carry out otter surveys of catchments within Cumbria and Lancashire on a 3 year cycle. Surveys in 2010 covered the rivers Eden and Lune. As otters are mostly nocturnal, the surveys consist of checks for signs of otters by looking for spraints and footprints under and around bridges.

In June 2010 an otter survey was carried out on the river Lune and Wyre.

100 sites were surveyed, 70 of which were positive for otter signs. This shows a large increase from the previous survey in 2007 when only 37 sites were positive. The river Lune and Keer were positive for 78 percent of sites, in 2004 only 50 percent of the sites were positive. Otters are found throughout the Lune catchment, and subcatchments of River Dee, Wenning, Greta and Rawthey. Dry weather conditions allowed plenty of evidence to be seen and 17 new sites across the catchment were found, including small upland streams. Signs were less frequent on River Hindburn and Keer, however otters are known to frequent some of these areas. Regular reports of sightings of otters in urban areas like Lancaster show the animals can adapt and tolerate some disturbance.

To the north the Lune catchment is bordered by the river Eden. For the 2010 Eden otter survey more than 200 sites were surveyed with 80 per cent showing positive signs of otters. This is an increase from 72 per cent in 2007. There were 13 new sites and the overall distribution throughout the Eden catchment appears to be widespread, with otter signs on all sub-catchments.

The fifth national otter survey of England examined over 3000 river sites across the country between July 2009 and March 2010. Existing data were used from the EA and Wildlife Trusts as well as additional surveys being carried out. The survey showed that:

• The number of positive sites has increased tenfold in 30 years, with positive site records increasing from 6 per cent in 1977-79 to 60 per cent in 2009-10.
• Since the last survey in 2002, positive site records have increased from 36 to 58 per cent.

Otters are now widely distributed on the Ribble and Lune catchments. These rivers provide corridors for re-colonisation of the catchments to the north of the urban area of Liverpool, Warrington and Manchester. The North West region has shown a major increase in otter range since the last survey in 2000-02. Regular surveys by Environment Agency staff show that otters have been slowly re-colonising the area. The results are of particular interest as no introductions have taken place in the region. It is thus one of the few areas where we have both a wholly natural increase in range, combined with a series of detailed surveys covering the period of re-colonisation.

The otter population is recovering following a ban on harmful pesticides put in place in the 1970s and legal protection given to otters, making it an offence to intentionally kill or harm the animal. Otters have also been helped by a significant improvement in water quality over the past 20 years, bringing fish back to rivers that were once polluted. The otter is at the top of the food chain, and as such is an important indicator of the health of English rivers. Improvements to water quality and habitat also mean salmon and other wildlife are returning.

A consequence of the recovery of otter populations has been an increase in reported otter road deaths, and the number of accidental deaths of otters remains a cause for concern. Dead otters reported to the Environment Agency form the basis a programme of otter post mortem and tissue analysis undertaken with Cardiff University. This work has shown that the current suite of chemicals monitored in otter tissue has declined to levels where they should not cause significant pathology.

If a dead otter is found please contact 08708 506506 (EA) and ask for the nearest biodiversity officer, who will collect basic details and information on location.

Tracking the otter’s recovery has demonstrated the benefits of long-term monitoring and the use of this iconic species to raise awareness of pollution problems and the benefits of action to improve the environment.