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

Volume 5 Pages 1 - 83 (March 1990)

Abstracts

The oil spill in Prince William Sound, Alaska 2
Pages 2 - 7 (Report)
Anthony R. DeGrange
Abstract
Following the Exxon Valdez oil spill in Prince William Sound Alaska, on March 24, 1989, treatment centres for sea otters were set up at Valdez, Seward and Homer. Otter survival rates were lower at Valdez than at Seward, probably because the animals collected were closer to the spill in time and space, and oil toxicity was at a maximum. Otters collected in Prince William Sound were predominantly female and pregnant or lactating. Weathered oil persists in otter habitats throughout the spill zone - long term studies are underway to assess the effects of this.
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Distribution of Lutra maculicollis in Rwanda : ecological constraints
Pages 8 - 16 (Report)
A. Lejeune and V. Frank
Abstract
The study of 10 rwandese lakes, where there are still quite important populations of Lutra maculicollis, has pointed out a few characteristics of the habitat favorable to the survival of these populations. The ecological constraints for the survival of these populations are: the abundance of small fishes, the continuity of the lake side vegetation, the absence of crocodiles and pollution by pesticides, and the low level of predation by man.
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Otter distribution and protection in South Africa
Pages 17- 23 (Report)
David T. Rowe-Rowe
Abstract:
This paper draws together current knowledge on the distribution of otters in South Africa.  Aonyx capensis is more widespread than Lutra maculicollis, which is adapted to feed on fish, and hence is limited to areas which can support them, whereas clawless otters are adapted to eat the more widespread crabs and frogs.  Otters are protected in reserves and national parks. Hunting outside of these areas is not a serious threat, but habitat degradation and loss due to rapid expansion of the human population.
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Recent Information on the Congo clawless otter
Pages 24 - 27 (Report)
David T. Rowe-Rowe
Abstract:
Distribution data for Aonyx congica is reviewed.  Little is known about the ecology of this species.  Over much of its range there is little human population, but elsewhere habitat degradation has occured.  There is a particular need for a detailed study of A. congica.
Contents | Full Text + Links | PDF (91 K)

Fish farming and otters in Finland
Pages 28 - 34 (Report)
Uolevi Skáren
Abstract:
The results of a questionnaire sent to all fishfarmers in Finland are presented; 45% replied. There appear to be good otter populations in Finland. Frequency and amount of damage to stocks is discussed. An electric fence system that has been found useful in excluding otters from fish farms is described. Only a few farmers consider otters a grave pest. The major threat to otters in Finland seems to be traffic accidents as car numbers increase. Further information is needed to confirm the findings, and to ensure confusion with mink does not occur.
Contents | Full Text + Links | PDF (152 K)

European otters and preventive measures in fish-fykes
Pages 35 - 40 (Report)
G.C.M. van Moll
Abstract:
Drowning in fish-fykes causes proportionally high mortality in a vulnerable otter population. Stop-grid mesh sizes recommended in Denmark and Great Britain assume that juveniles do not enter the nets unless following adults - this is not the case in the Netherlands. A smaller grid size is recommended, which may also improve the quality of eel catch.
Contents | Full Text + Links | PDF (101 K)

Restoration plan for the otter habitat in the Netherlands
Pages 41 - 44 (Report)
Just Walter
Abstract:
This paper reviews the provisions of the new otter recovery plan for the Netherlands, launched in July 1989.  Threats to otters are reviewed, and mitigation measures specified, along with maximum levels of pollutants.  Improvement in water quality is the first aim of the scheme.  A principal role is given the the Stichting Otterstation Nederland.
Contents | Full Text + Links | PDF (98 K)

The End of the Otter and of Otter Reintroduction Plans in Switzerland
Pages 45 - 50 (Report)
Darius Weber
Abstract:
Otters are now extinct in Switzerland. Switzerland has to be considered as a country where viable otter populations cannot exist now and in the foreseeable future, because PCB levels in fish are much too high and not decreasing. Reintroduction programs cannot be justified. The message to the public is that sometimes nature cannot be repaired, pollution is out of control and we must learn from the lesson of PCB-caused otter extinction.
Contents | Full Text + Links | PDF (118 K)

Otters and bio-accumulating pollutants: first data for western France
Pages 51 - 60 (Report)
Lionel Lafontaine, Guy Joncour and Patrick Menanteau
Abstract:
Otters are still common in eastern France but extinct in the west. Following the deaths of three otters in Brittany, the authors analysed the specimens for pollutants, and compared the results to those found in Mink in the same area. This is the first such assay done on aquatic mammals in France. This preliminary study has allowed the authors to demonstrate contamination of wetlands by several pollutants: the presence of PCBs, mercury and in a tiniest measure Dieldrin and lead, is worrying, or at least preoccupying, for two water basins in western France. It confirms also that investigations must not be limited to insignificant measures as concerns water, sediments, moss or cyprinids, but must focus equally and especially on aquatic predators: salmonids, pike and carnivorous mammals. Also the particular importance of these basins for human populations and economic activities dependent on water quality (oyster faming, for example) would merit an alertness on the part of local authorities.
Contents | Full Text + Links | PDF (270 K)

Some observations on the otter population in the Homen catchment (N.W. Portugal)
Pages 61 - 68 (Report)
Anabela Trindade
Abstract:
It has always been assumed that the otter population was good in Peneda-Geres National Park in northern Portugal. This study examined the River Homem catchment in detail, and found that the population was less good than expected, and isolated from other otters by the reservoir of the Vilarinho das Furnas dam. The authors consider that the current dam-building policy is not conducive to the conservation of otters.
Contents | Full Text + Links | PDF (103 K)

Otter survey of the Isle of Skye, Scotland (Lutra lutra)
Pages 70 - 75 (Report)
Grace and Paul Yoxon
Abstract:
A survey of otters on Skye is being undertaken in order to develop a method of systematic recording of otter sightings, and to increase public awareness and interest in otters.  Skye has a good population of mainly coastal otters.  The results to date are presented and discussed. There appears to be little correlation of sightings to tidal state, and the animals seem to be mainly diurnal; there is evidence of a breeding season which may correlate with food supplies.
Contents | Full Text + Links | PDF (212 K)

Fluctuations in the otter population of parts of south-west England
Pages 76 - 78 (Report)
James Williams
Abstract:
The author has kept detailed records of otter sightings in a 4100 sq km area of south-west England since 1969.  Otter numbers declined dramatically until 1984, with many rivers showing no otters whatsoever for long periods, and recolonisation attempts by transient animals failing to establish.  Since 1988, otter numbers have started to recover, but surveys must continue to discover whether this is a true recovery or if otter numbers will once again decline.
Contents | Full Text + Links | PDF (92 K)

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