IUCN/SCC Otter Specialist Group Bulletin
© IUCN/SCC Otter Specialist Group

Volume 2 Pages 1 - 58 (March 1987)

IUCN/SCC OSG Group
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Second Working Meeting of OSG (European Section)

The European Section of the Otter Specialist Group held a working meeting at Kaposvar, Hungary in May, 1986. Members from many western European countries attended but unfortunately, despite the location, eastern Europe was represented only by Hungary and Bulgaria.

From the discussions on research and conservation measures carried out so far, it was clear that much more precise information is needed on the habitat requirements of otters. We have little idea of their minimum requirements which makes it difficult to predict the impact of various forms of habitat destruction. Typically, in much of western Europe, otter numbers are low with animals often living in what appears to be sub-optimal habitat and yet we know almost nothing about their behaviour under such conditions. Radio-tracking data are few and such studies have largely been carried out in regions with "good" otter populations. We need information from radio-tracking in a wide variety of habitat types. The delegates in Hungary recognised that this type of study on a low population could pose several problems. It could, for example, prove difficult to catch the animals and there is always the possibility of detrimental disturbance to an already threatened local population. It may be that the number of animals that could be caught and tracked would be too low to provide definitive, useful information. However, since much general conservation effort is now being expended on fragmented populations, efforts should be made to overcome such difficulties.

More information is also required on pollutant levels in otters and delegates agreed that every effort should be made to arrange for analyses of tissues from all available dead otters. We need comparative data on levels of different pollutants, on veterinary post-mortem reports and on histological examinations of tissues. Material from "normal", healthy otters is also required for purposes of comparison.

Mats Olsson from Sweden presented data on the effects of organochlorine (especially PCB) contamination on seals from the Baltic, e.g. sores on the flippers, upturned and elongated nails, erosion of jaw tissues, tumours etc. He strongly implicates PCBs in the declines in otter populations. Significant levels of PCB have been recorded in tissues of some British otters and it was of interest that a few of these animals displayed symptoms apparently similar to those described in Baltic seals. As Olsson pointed out, PCBs are derived from industrial processes but even a small workshop can cause significant contamination of the local waterway.

It was agreed that all otter tissues should, as a matter of course, be analysed for organochlorines, viz. PCBs, dieldrin, lindane and DDTs and for metals. Delegates from Britain and Sweden offered to try to assist countries lacking the facilities for analyses.

International cooperation is essential in this matter. At present, as was pointed out, in some countries (e.g. Eire, Hungary) tissues are available but no analyses are carried out while in others (e.g. Britain) certain agencies perform analyses but choose not to make their results available. We now have some idea of the approximate status of otter populations in different countries and comparative data on pollutant levels are urgently required to further European conservation efforts.

During the meeting in Hungary, one day was spent in the field visiting fish ponds. In some parts of Hungary, judging by the abundance of otter signs, the animals are relatively numerous. It is unusual to-day to find thriving otter populations in lowlands subject to intensive agriculture. In Hungary there is a conflict between conservationists and fishfarmers who claim financial losses due to otter predation. The government agencies issue some licences to kill otters at fish ponds but many more animals are destroyed illegally. This problem is not confined only to Hungary (e.g. also Bulgaria) and it would be valuable to know more about the behaviour of otters at fish ponds. Nothing is known of range sizes of animals living in areas of ponds or of their use of the ponds as opposed to other available water bodies. The true level of predation at fish ponds is unknown. It seems that otters may be more numerous in some series of ponds than in others and while the habitat varies (e.g. some ponds were surrounded by marsh and wet woodland), it may be that illegal killing is, in places, depressing numbers. The Hungarian delegates were urged to initiate radio-tracking programmes which could help to clarify the situation.

Copies of the recommendations made at the meeting are available from either of the co-ordinators of the European Section.

Sheila Macdonald,
Department of Biology,
University of Essex,
Wivenhoe Park,
Colchester,
United Kingdom.

Postscript:
We have just heard from Geko Spiridonov that Lutra lutra has now been given full protection in Bulgaria - even at fish farms where animals were previously killed.

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