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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