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The weekend of 21-25 September saw scientists from the Netherlands, Spain, France, Denmark, Switzerland, Norway, Belarus, Poland, Slovakia, Hungary, Czech Republic, as well as from all over the UK, converge on the Isle of Skye. And why? For the first ever international conference on the effects of pollutants on otters and the increased risk of disease.
The event, organised by the International Otter Survival
Fund, brought together these experts to look at the present status of the otter
in Europe and the long-term effects of pollutants and also to develop protocols
for future work.
The whole meeting was a positive and enthusiastic exchange
of information and experience. Some
people came from countries like Switzerland and the Netherlands where otters are
now extinct and they hope to be able to bring them back;
those from Eastern Europe, and of course we on Skye, have healthy
populations, but all appreciated the vulnerability of these animals with the
threats of pollution. By combining
our knowledge we can develop work which will encourage otters back in some areas
and safeguard them in others.
The venue of Sabhal Mor on the Isle of Skye provided a wonderful setting and the focus point of the conference was endorsed by great views of otters in the wild – for some their first ever truly wild otter.
Otter watching on Skye
Here below is a report from the conference.
The conference opened with Dr Jim Conroy from the Centre
for Hydrology and Ecology in Scotland describing the small increase in the otter
population throughout Europe but there are dangers from a whole variety of
pollutants so that we should not be too complacent.
Dr Don Jefferies of the Vincent Wildlife Trust , described
some of his pioneering work on the effects of organochlorines on birds and
mammals over the past 40 years . He
was one of the first to demonstrate the decline of the otter in the 1950’s as
a result of these organochlorine chemicals. This decline started suddenly in
1957 and occurred all over the country and by 1977 when proper surveys were
undertaken the population was severely reduced.
Today the situation is a lot more healthy as we recognise
this particular problem but other chemicals are becoming an increasing worry.
Dr Arno Gutleb from the Toxicology Group at Wageningen
University in the Netherlands talked about the dangers of Polychlorinated
Biphenyls (PCB’s) and the strong correlation between PCB levels in otter
tissue and the status of otter populations:
in areas with average PCB levels above 50 mg/kg otter populations
decreased or became extinct. Dr
Gutleb went on to explain that PCB levels bring down vitamin A levels in the
otter’s body and all animals need vitamin A in order to fight off disease.
Dr Gutleb also pointed out the problems of mercury in the
environment and the high levels of naturally occurring mercury.
Because of this high natural background level it is very easy to push
levels above dangerous limits. Mercury
is released into the air naturally, but also from the burning of household and
industrial waste, and especially from burning coal and other fossil fuels.
Mercury in the air condenses on to particles and returns to the earth in rain or
snow. Once in the water system it is converted to methylmercury by
bacteria and chemical reactions. The
fish that live in these environments absorb this through their gills and from
the prey they eat, so as the otters eat the fish they accumulate high
concentrations of methylmercury in their bodies. At high levels the nervous system is damaged, the
foetus is damaged and the life expectancy of the animal is halved.
In adult otters the first symptoms are inco-ordination and the inability
to walk normally.
In some parts of Europe the otter does not live long in the
wild and this is causing increasing worries about the long-term future of the
population. As the otter does
not reproduce until about 2 years old there may be little opportunity for the
animal to replace itself within the population.
Other talks included:
*Disease in British otters by Dr Vic Simpson of the Veterinary Investigation Centre in Cornwall
*The pollution effects on otter populations in SW Europe by Dr Jordi Ruiz-Olmo (Spain)
*The pollution effects on the aquatic ecosystems in Belarus by Dr Vadim Sidorovich
*The importance of pollutant data and re-introductions by Dr Addy de Jongh (the Netherlands)
*Disease in Danish otters by Dr Aksel Madsen
*The pollution effects on otters in Eastern Europe
The overall aim of the conference was to have an integrated
approach in Europe for pollutant analysis and to ensure that quality control
measures in all European labs are the same.
Dr Richard Shore of the Centre for Ecology and Hydrology in England
emphasised that we must have this uniformity between European labs so that
levels of pollutants can be compared between countries and dangerous levels
detected.
Dr Vic Simpson presented protocols on post mortem analysis
and the final session, chaired by Lyn Jenkins of the Environment Agency, brought
together all this research under an Integrated European Research programme,
Dr Paul Yoxon of the International Otter Survival Fund stated that this conference had been a great step forward in future pollutant analysis and the effects on otters; if we want to have healthy otter populations in the future we must this base line data now. In the 1960’s the otter nearly disappeared from the UK because of the continual use of organochlorines. We now know of the dangers of PCB’s and mercury but we have a number of chemicals now in use and we know little or nothing about their effects on the otter. The otter, after all, is a great bio-indicator and if this animal at the top of the food chain is being affected and declining then the chemicals can ultimately effect our human population.
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