OTTERS RETURN TO THE DON
IT IS a blink-and-you’ll-miss-it moment. However, while the first ever on-screen appearance of an otter in the Peak District might last just a few seconds, its environmental significance could be much more long lasting.
The footage, showing an otter marking its territory on the banks of a river, was filmed by Dr Douglas Ross, a volunteer on a project being led by the University of Sheffield, which is helping to chart the slow but steady resurgence of the creatures once on the verge of extinction in the UK.
“It’s amazing to watch,” says Dr Deborah Dawson, who is based at the university’s department of animal and plant sciences. “Otters are nocturnal creatures. Even in areas where we know they exist they are incredibly difficult to spot, so the fact that this is the first one caught on camera in the Peak District is something really special.”
Otter numbers crashed in the UK from the mid-1950s onwards, with the introduction of powerful agricultural pesticides partly blamed for their decimation. By the 1970s, as residues from these chemicals began to build up in waterways, otters had all but disappeared from large parts of the country. The North of England was particularly badly hit and many feared that the animals were gone forever.
“Fifty years ago, the River Don was one of the most polluted rivers in Europe and as a result it wiped out the population of otters which had been living in the region,” says Dr Dawson. “It wasn’t alone. Over a relatively short period, Britain’s’ waterways had really taken a hit and by the time people started to analyse what was going on much of the natural habit was already in critical condition.”
The first national otter survey, which was carried out between 1977 and 1979, confirmed the worst. Of the 2,940 sites looked at, just five per cent were still home to otters and the news sparked a major conservation effort.
“There isn’t one single reason why otter numbers have increased, rather it is a combination of circumstances,” says Dr Dawson. “Bans on various pesticides were introduced, there has been increased legal protection, more general improvements in water quality as well as targeted conservation efforts.
“Together these have all created an environment where otters can thrive. However, even with all those measures, recovery has still been slow in the North of England. We are not entirely sure why, but our aim now is to work out what we can do to encourage more of them to come back.”
Earlier this year, signs of otter life were detected in South Yorkshire when researchers conducted the first ever DNA survey of numbers in the North of England.
Working in collaboration with the University of Leeds and the Sheffield and Rotherham Wildlife Trusts, Dr Dawson and her team began analysing otter droppings, known as spraint, which revealed that a small population had returned to the Sheffield stretch of the river for the first time in almost half a century.
“We were able to detect seven otters, including at least two males,” she says. “Interestingly our research also showed that otters were popping up in urban, suburban and rural locations across the whole of the South Yorkshire region with one female detected in quite remote area north of the city.
“Females can travel up to six miles, males up to 24 miles and previous studies have suggested that otters can have very large territories that do not overlap. While it is therefore unlikely that more than one adult male or one mother with cubs is resident in Sheffield, if we are going to support the otter population to grow then we have to make sure the passage through the city and along the River Don remains as clear as possible.
“If that is to happen, we have to hope that many of the current and planned riverside developments can be done sympathetically to allow the current wildlife populations to thrive.”
The otter comeback is one of English nature’s real success stories. Between 2000 and 2002 when the fourth otter survey was carried out, more than 36 per cent of the original sites revealed traces of the animal. Six years ago when otters were found it Kent, the animal had a presence in all counties in England once again.
Much of the increase has been down to natural recovery, but in the early 1980s Natural England, working with the Otter Trust, also developed a reintroduction programme to repopulate parts of Eastern England with captive-bred otters.
Between 1983 to 1999, 117 captivebred otters were released mostly on East Anglian rivers and a separate programme saw 59 wild otters, which had been rehabilitated after being orphaned or injured, given a new home in Yorkshire.
By the early 1990s it was decided that reintroductions were no longer necessary. However, the various otter populations still need monitoring to ensure their long-term health and now Dr Dawson is looking to secure funding to continue the DNA project.
“We were fortunate that we had a visiting MSc student to help with the initial analysis and now we are looking for a further £2,500 so we can really make the most of this project,” she says. “To be able to use genetic analysis to investigate otters on the River Don and learn more about this very elusive mammal has been our amazing experience. Our results match well with previous records of otter presence which had been based on sightings around Sheffield, but we were able to take this further to produce the first DNA-based estimate of otter numbers in the regions.”
Once complete, it is hoped the project will help pinpoint likely barriers preventing the otters moving into different areas and provide conservation groups with a blueprint to map other populations in different parts of the country.
While the original threats of pollution may be no more, the future of the otter is not entirely assured with severe flooding, increased road traffic and habitat loss all having been identified as causing potential harm to existing populations.
“The fact they are in the River Don demonstrates that there must have been significant improvements to the water quality, but through the DNA analysis we can also identify what their diet consists of. Once we know what other species are present then that will give us an even more detailed picture of the health of the river.”
Dr Ross said: “Seeing this footage and knowing the otters are moving around the Peak District is really exciting and the potential to use spraint DNA to identity the specific individual and its diet makes it all the more personal.”
Dr Dawson is keen to find out more about Sheffield’s otter distribution in the Peak District. Anyone interested in the project, including potential sponsors, can email d.a.dawson@ sheffield.ac.uk
To watch the otter footage go to yorkshirepost.co.uk