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

Volume 8 Pages 1 - 47 (February 1993)

Abstracts

Survey of a Translocated Sea Otter Population
Pages 2 - 4 (Report)
Ronald J. Jameson
Abstract
The Washington sea otter population is important because it is the only one having the dual distinction of becoming successfully established and being intensively monitored. Fifty-nine sea otters were released off the west coast of the Olympic Peninsula of Washington State during the summers of 1969 and 1970; all had been translocated from Amchitka Island, Alaska. In 1970, 30 otters were released. Surveys to assess the results of this translocation began in 1977. Since we began our current survey method in 1989, the population has grown, despite the oil spills of 1988 and 1991, at an average rate of about 16 % a year. In 1991 a large group broke away from the main population and established itself in Makah Bay about 15 km north of where they were the previous year. Females with pups now occur from Duk Pt to Destruction island.
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Otters and Gillnet Fishing in Lake Malawi National Park
Pages 4 - 6 (Report)
Lance Smith
Abstract
At the south end of Lake Malawi, the small national park is home to spotted-necked and Cape clawless otters. The park contains five enclaved villages that depend on gillnet and longline fishing for their livelihood. The author surveyed the fishermen of Chembe village for fishing methods, gear and problems with animals. Theft of fish from nets by otters was complained of, but there were no reports of otters drowning in gillnets. The author intends to extend his survey to the other four villages in Lake Malawi National Park.
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Resource Use within the Crab-Eating Guild in Upper Kairezi River, Zimbabwe: Proposed Project
Pages 6 - 9 (Report)
James Butler
Abstract:
The management problem that this study will address is the apparent decline in the biological productivity of the Upper Kairezi River for rainbow trout. Fishery managers believe that the cause could be predation on trout by resident Cape Clawless Otters and the African mottled eel. The area is part of a CAMPFIRE (Communal Areas Management Programme For Indigenous Resource) programme and agriculture is excluded from the environs. However, owing to the falls in catches, fishermen have been discouraged, generating insignificant revenue from the KRPA and undermining local commitment to the conservation of the resource and its flora and fauna. This study aims to investigate competition between the otters, eels and trout for the river crab food resource, the form and extent of resource partitioning occurring among the predators and the predator-prey relationships between the otters and eels (predators), on trout (prey). Without this evidence, the danger is that the Cape clawless otters of the Upper Kairezi will be relegated to vermin status and controlled as such before scientific evidence has been produced to prove their innocence.
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Ťreboň Biosphere Reserve Otter Project
Pages 10 - 12 (Report)
Robert Dulfer
Abstract:
A project on the ecology of otters in the Ťreboň Biosphere Reserve is proposed. Until recently, this network of man-made wetlands has been excellent otter habitat, with sustainable exploitation by both man and nature. In recent years, economic factors have led to this balance being distorted in man's favour, with habitat destruction, pollution and calls for compensation for otter damage to fish farms, and even the right to kill otters. Little is known of the current status of the otter population in the reserve, and this project aims to address this and to form a Ťreboň Otter Protection Plan.
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The Eurasian Otter on the Thainguen Plateau (Vietnam)
Pages 12 - 13 (Report)
German Kuznetzov, Kazimieras Baranouskas and Pham Trong Anh
Spraint surveys were carried out in two locations on the Thainguen Plateau, in northern Zilai province, Thailand in 1989-90, for Lutra lutra barang. Fish, amphibians and crabs form most of the diet. Spraints in wooded areas were mostly on logs and stones in rivers, but in open areas, they are found on the river banks. Where otter spraint is found, no other droppings of carnivores that mark territory thus were found. The otters moved about 3 km per day. In places of plenty of food and holts they can stay for some days. After 15-20 or more days otters again cover the same route within their home range.
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The Neotropical River Otter Lutra longicaudis in Iberá Lagoon, Argentina
Page 13 - 16 (Report)
Anibal Parera
The neotropical river otter has suffered intense hunting pressure in Argentina.  Over the last two decades, hunting has decreased.  A survey was carried out in an area where otters appear to be abundant, the Iberá Swamps and Lagoons Reserve, where the government has concentrated conservation efforts.  A good population was found here and in several other lagoons in the reserve, but not in the total area because hunting is not controlled in most of the large extension of the reserve.
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Total Mercury and Methylmercury Levels in Fish from the Department Madre de Díos, Peru
Page 16 - 18 (Report)
Arno C Gutleb, Christof Schenck and Elka Staib
Very little is known about environmental contamination in most otter species.  In the range of the Giant Otter, Pteronura brasiliensis, gold miners discharge a great deal of methylmercury into the environment, and this is known to biomagnify in the food chain.  Assays for methylmercury were carried out on fish collected in the Madre de Dios department of Peru, from near gold mining areas, and also from more than 100km away; additional fish were obtained from fish markets.  Results show that significant contamination occurs in fish bigger than the normal prey size of the otters, but at present, there are low levels in prey species - this should be monitored closely in future.
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Organochlorine Contaminants in Spraints from Captive Otters
Page 18 - 19 (Report)
Chris Mason
Assays for DDE, Dieldrin and PCBs were carried out on captive otters to provide a baseline of presumed uncontaminated animals for comparison with results from surveys in the wild.  Results for captive animals were much lower than those from upland Wales, which has a thriving population of wild otters.
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Relationships between PCBs in Otter Livers and Spraints from Gut and Environment
Page 20 - 21 (Report)
Chris Mason and Liam O'Sullivan
Spraints from 29 otters found dead in south west Ireland during 1984 - 90 were analysed for PCBs, and the levels compared with those in the livers of the same animals.   A strong correlation was found, indicating that spraints can be used to estimate PCB pollution burden in live otters.
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Aktion Fischotterschutz e. V. (German Campaign for Otter Protection): Activities 1992
Pages 21 - 22 (Report)
Claus Reuther
This report covers captive animal studies during period, studies in the wild including one on avoidance of otter road traffic casualties commisioned by the Ministry of Traffic, which will be used to inform new highway building, two surveys and a pollution assay in 6 states showing poor otter numbers correlate with higher PCB levels. A habitat management programme, Otter 2000, establishing migration corridors for otters was initiated. There has been good progress with the revitalisation of the River Ise. The Otter-Zentrum itself has had a very good year, with high visitor numbers and many new births.
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Behaviour of Otters in a Coastal Marine Habitat: Abstract of Work in Progress
Page 23 - 27 (Report)
J. Scott Shannon
After reviewing the history of the study, the sudden and catastrophic loss of all three breeding females is described.
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The Otterpark Aqualutra
Page 28 - 29 (Report)
Addy de Jongh and Karin Bavinck
The activities of the Dutch Otterstation Foundation (SON) are described, notably the foundation of Otterpark AQUALUTRA,which consists of a breeding centre, a research centre and a visitor centre. Each of these is described in turn. The Otterpark is situated in the "Groene Ster" nature reserve near Leeuwarden, Friesland, Netherlands.
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The Otter in Lithuania
Page 29 - 31 (Report)
Eduardas Mickevičlus
Official otter counts in Lithuania are not well-done, and underestimate the otter population.  In fact, otters live in all 44 regions of Lithuania.  Otter hunting is illegal in Lithuania.  Conservation efforts concentrate the otters' habitat, establishing a network of reserves protecting the small rivers of the country.
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Food of Lutra lutra in Central Finland
Page 31 - 34 (Report)
Uolevi Skarén
In the years 1988-1992 3095 faeces of otters were analysed in YIä-Savo, Central Finland. Because the report (Skarén 1992) was written in Finnish, I present the main results here.  Fish are the preferred prey, some carrying significant pollutant burdens, but in winter, frogs are significant.  Muskrats are also frequently eaten in winter.  Crayfish are rare in the area due to disease, but where present are eaten, and presence in spraint could be used to track the recovery of crayfish populations. 
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Artificial Food Support for Lutra lutra in a River in Spain
Pages 34 - 36 (Report)
Jordi Ruiz-Olmo
In the Spanish Pyrenees, otters are only present in six rivers, and populations are fragmented by hydrological schemes, and high, dry mountains. Because of the great water level fluctuations caused by hydroelectricity generation, fish levels often drop very low, endangering the otters. It was decided to restock one of the rivers, the Noguera Ribagorçana, with two species found below the dams and thus native to the river, which are better able to cope with high fluctuations in water level. An ongoing monitoring program shows otters are using this new resource.
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Otter Distribution and Conservation in the Czech Republic
Page 36 - 37 (Report)
Václav Hlaváč and Ales Toman
The otter has been protected in the Czech Republic since 1949. A survey of otters was made during the last four years. A large population exists in the south, a smaller one in the east and a much smaller one in the north. Conservation activities concentrate on pollution levels, which are giving cause for concern, breeding and reintroduction, in collaboration with the Dutch Otterstation, to bridge between the isolated populations, and habitat restoration.
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Distribution of Lutra lutra in Brittany and First Preventative Measures against Road Traffic
Pages 37 - 39 (Report)
Lionel Lafontaine
Otters are relatively common in Brittany unlike the rest of France. A survey was carried out from 1986 to 1990, which showed good otter numbers in the inland third of the country, correlating strongly with areas of good water quality. There is some evidence of otters spreading out to adjacent areas. A large consultation exercise aimed at preventing otter deaths on roads has led to enforcement of the 1976 Nature Conservation Act to protect otters. As a result of this, many otter underpasses have been built under roads, and a survey has been commissioned to assess their efficiency.
Contents | Full Text + Links | PDF (60 K)

Field Survey of Lutra lutra on Corfu Island (Greece)
Pages 39 - 42 (Report)
Xavier Grémillet
A study on Corfu Island in 1986 describes an otter population strongly threatened by building activities and pollution from olive pressing factories. This present report shows the accurate situation in 1992. Otters no longer breed on the west coast, where two major populations have been extirpated. Pressure from tourist development, fishfarming and uncontrolled poaching, even in reserves, threatens remaining otter populations. Conservation and restoration of the remaining wetlands is urgently needed.
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