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IUCN/SCC Otter Specialist Group Bulletin
© IUCN/SCC Otter Specialist Group
Volume 16 Issue 2 Pages 58 -
110 (October 1999)
Abstracts
Protecting Otters in a Non-Megadiverse
Third World Country
Pages 63 - 64 (Viewpoint)
Alvaro Soutullo
Abstract
The world-wide protection of areas of great conservation value
should be everybody's concern, as the loss of biological
diversity is everybody's problem. As most of these areas are
located in poor or developing countries with few opportunities
to invest in biodiversity conservation, the rest of the
countries, and especially those with better economic conditions,
should support the protection of those key areas. Although
people in third world countries are involved in the development
of these areas, the impetus and equipment for the change is
usually from elsewhere, and the products and profits usually
also go elsewhere. Why then should only the local people
be held responsible?
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Survey of Danish Free Living Otters Lutra
lutra - a Consecutive Collection and Necroscopy of Dead
Bodies.
Pages 65 - 76 (Article)
Aksel Bo Madsen, Hans Henrik Dietz, Per Henriksen and Bjarne
Clausen
Abstract
During 1979-1993 194 dead Danish otters Lutra lutra were
received. Of these, 145 were necropsied and the cause of death,
sex, age and body condition determined. Traffic mortality
(45.4%) and drowning (32.5%) constituted the major cause of
death. Shot-gun lead pellets were detected in 5% of the otters.
Inclusion bodies indicating distemper virus infection were found
for the first time in a free living otter population. Angistrongylus
vasorum larvae were found in the lungs of free living otters
for the first time. No ectoparasites were found. Infectious
agents were detected in 22.1 % of the otters although only few
otters appeared to have died from infections. The age
distribution was not significantly different between the two
sexes. Body condition for otters, which died violently in
Denmark was comparable to findings in Shetland, where thriving
populations exist. The results showed a considerable decrease in
number of otters found drowned in fish traps coinciding with the
introduction of stop grids in fish traps in 1986. The results
suggest that the existing otter population in Denmark is healthy
and in good condition but it cannot be excluded that the large
number of otters killed by traffic threatens the continued
expansion of the species.
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Comparative Analysis or the
Helminthocenoses of the Native Semiaquatic Mustelids (Lutra
lutra, Mustela lutreola) in Connection with the Width
of Food Spectra
Pages 76 - 78 (Report)
Vadim Sidorovich and Elena I. E. Anisimova
Abstract:
The helminth fauna of mink (Mustela lutreola) was
compared with that of otters (Lutra lutra) and found to
be more diverse. This probably reflects the fact that
otters are more specialist predators than mink, and therefore
exposed to fewer infesting sources of eggs and larvae.
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(38 K)
Results of the 1999 Survey of the
Reintroduced Sea Otter Population in Washington State
Pages 79 - 85 (Report)
Ronald J. Jameson and Steven Jeffries
Abstract:
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. Up to 1989, the
population has grown at near the maximum rate of increase (rmax)
for sea otter populations of 17-20% yr-1. Since 1989,
however, the rate of increase appears to have declined to about
11% yr-1. The results of the survey this year are
encouraging and indicate the population has been growing at a
finite rate of about 11% since 1989.
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K)
Report on the Rehabilitation and Release
of Two Giant River Otter (Pteronura brasiliensis) Pups in the
Bita River (Vichada, Colombia)
Pages 86 - 89 (Report)
Juan Ricardo Gómez, Jeffrey P. Jorgenson and Ricardo Valbuena
Abstract
Two Giant Otter (Pteronura brasiliensis) cubs were
rehabilitated and released successfully and adopted into wild
otter groups. The protocol used is presented. For a
successful rehabilitation and release program, it is necessary
to understand the basic ecology and behaviour of the species, as
well as to have the appropriate facilities, feeding protocols,
and adequate veterinary services available.
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An Overview of the Giant Otter-Fisherman
Problem in the Orinoco Basin of Colombia
Pages 90 - 96 (Report)
Juan Ricardo Gómez and Jeffrey P. Jorgenson
The giant otter faces a new threat in the Orinoco Basin because
fishermen in that area see it as a competitor. This study
examines the species of fish caught by commercial and sport
fishermen in the area and compares it to the species eaten by
the otters. Although overlap exists in some of the families of
fish that the otter consumes and those that the fishermen of the
area extract, the competition for fish is minimal. Although we
cannot ignore that a problem exists between otters and in
particular the commercial fishermen, this is not because of any
impact that the otter has on the populations of fish. Rather,
the problem can be attributed to the local inhabitants' lack of
information about the importance of the otter as a key species
of the ecosystem.
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K)
Contaminants in Otter, Mink and Marten
in British Colombia
Pages 97 - 101 (Article Summary)
Lee Harding
As a continuation of studies of mustelids on the Columbia and
Fraser River systems in north-western North America, chlorinated
hydrocarbon and trace metal contamination of mink, marten and
river otter were assessed in relation to physiological and
reproductive measures of condition. Mink, marten and river otter
were collected during the winters 1994/95 and 1995/96 from
commercial trappers. Necropsies included evaluation of the
following biological parameters: sex, body mass and length, age,
thymus, heart, liver, lung, spleen, pancreas, kidney, gonad,
omentum, adrenal gland and baculum (in males) masses, baculum
length, and stomach contents. Livers were analysed, individually
or in pools, for residues of organochlorine (OC) pesticides,
polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and
dibenzofurans (PCDFs). Contamination levels were relatively low
compared to those documented in other North American
populations, although they ranged higher than those detected
during an earlier survey (1990-92) of these regional
populations. Nutritional condition varied slightly amongst
collection regions, but showed no relationships with contaminant
burdens. Specifically, mink from the upper Fraser River appeared
to have less fat stores (evaluated by stomach contents and
omentum mass), but also showed some of the lowest OC
contamination levels observed. Similarly, a few individuals with
enlarged livers and kidneys had unremarkable contamination
profiles. Although a few individuals with gross abnormalities of
reproductive systems did not show high levels of contamination,
there was a significant negative correlation between Aroclor
1260 concentrations and baculum length in juvenile mink. The
influence of baculum length on reproductive success is unknown,
but given similar associations found in juvenile otter from
Oregon, the incidence of smaller baculum size and its influence
on reproduction needs to be further characterized in a larger
subset of these populations. Also, the bias against collection
of females introduced by using commercial traps may
underestimate the true contaminant burden in the subset most
likely to show detrimental reproductive effects. Other means of
collecting breeding-age females should be explored.
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