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

Volume 19 Issue 2 Pages 62 - 110 (October 2002)

Abstracts

Influence of Selection of Bank Side on the Standard Method for Otter Surveys
Pages  (Article)
Morten Elmeros and Neel Bussenius
Abstract
The effectiveness of the standard method used to survey otters can be affected by the choice of which stretch of bank is examined. The sensitivity of the standard method was evaluated in two regions with differing otter (Lutra lutra) population densities by surveying 300m stretches of bank from bridges on both upstream and downstream banks, in a region with a high population density, 64% of the 'positive' sites would be recorded as positive, regardless of which stretch of bank the surveyor chose. When using the standard survey method in a sparsely populated region, as few as 9% of 'positive' sites would be recorded if the choice of riverbank were not optimal. Examination of 100m of all four banks improved the success rate of the survey substantially in the sparsely populated region. The study suggests that the standard method is very sensitive to the selection of the stretch of bank in sparsely populated areas. The accuracy of the standard method can be increased with little extra effort, if survey guidelines are changed from "an optional search" of both banks under bridges to "an obligatory search".
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The River Otter (Lontra canadensis) in Clarcke County (Georgia, USA) - Survey, Food Habits and Environmental Factors
Pages 75 - 86 (Report)
Rienk Noordhuis
Abstract
The status of the river otter (Lontra canadensis}. was surveyed in and around Clarcke County (Georgia, USA). Although nearly extinct in the nineteen fifties, the otter population appears to be well developed today. Food habits were analyzed through spraint analysis using spraints collected in winter and summer. Sunfish and crayfish were found to be the most important food items. An attempt was made to find out if otters in the study area are affected by environmental pollution. Literature data and heavy metal analysis showed that the exposure to chemical pollution has been relatively low. The siltation of the rivers and creeks does not appear to harm the river otter or change it's food habits.
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Distribution and Population Status of the Giant Otter Pteronura brasiliensis in Bolivia
Pages 87 - 96 (Report)
Paul van Damme, Rob Wallace, Karen Swaenepoel, Lillian Painter, Silvia Ten, Andrew Taber, Rocio Gonzalez Jimenes, Isabel Saravia, Anna Fraser and Julieta Vargas
Abstract:
The giant otter (Pteronura brasiliensis) is one of the most endangered mammal species in the Neotropical region. In Bolivia, it has been reduced to very low population numbers as a result of poaching in the 40s and 70s. Recently, 14 researchers on the giant otter, who together estimated that around 350 individuals exist in Bolivia, published a preliminary distribution map. In this report, we briefly present the most recent information on the distribution and population status of this species in the Bolivian Del Plata and Amazon river basins. Moreover, we comment on the superposition of giant otter family groups, hydro-ecoregions, and National Parks. Finally, we present a short discussion on the possibilities of interchange between Bolivian giant otter subpopulations..
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Historical and Actual Presence of the Giant Otter (Pteronura brasiliensis) on the Lower Meta River, Department of Casanare - Colombia Orinoquia
Pages 97 - 102 (Report)
Hernán Javier Díaz and Iván M. Sánchez
Abstract:
There has been little information published about the distribution of giant otters (Pteronura brasiliensis) in Colombia, and recent distribution maps have failed to include the Department of Casanare as having giant otters present. Some ancient chronicles, however, record giant otter occurrence in the Colombian Orinoquia, as well as the value of its skin. It is believed that since 1974, when the commerce of skins ceased in Colombia, populations of this species have recuperated in this area. In this paper we confirm the presence of giant otters in this part of the country, and provide identification of individuals sighted through neck patterns.
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New Information on the Predation of Fish Eating Birds by the Eurasian Otter (Lutra lutra)
Pages 103 - 106 (Report)
Jordi Ruiz-Olmo and Rosa Marsol
Abstract:
The Eurasian Otter (Lutra lutra) mainly eats aquatic and semiaquatic prey (such as fish, crabs, amphibians and snakes), although in some plaxeces, and at some times, mammals, birds and insects can represent a significant part of the diet. A meticolous review of the literature shows a few cases of otters preying on large birds. Three cases are examined: a heron killed and eaten by a wild otter in the Pyrenees, gulls killed and eaten by an escaped otter near Barcelona, and a red kite caught by a captive otter, but rescued by staff, at the Pont de Suert otter centre in the Pyrenees. Further research is needed to establish whether otters are superpredators of birds and play a role in population control.
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