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Threats
to Sea Otter Recovery
On the west coast of Vancouver Island, the largest threat
to sea otter recovery remains oil spills. As little as a teaspoon
of oil is enough to destroy the water repellent and insulating
properties of sea otter fur, thereby causing heat loss and
potentially death by hypothermia. In addition, sea otters
ingest oil through grooming themselves and eating contaminated
shellfish, which damages their internal organs. Sea otters
return to the same areas to forage, which means they would
return to oiled areas, particularly kelp beds which can collect
and retain oil for long periods of time. Because sea otters
group in rafts, a substantial portion of the breeding population
can be wiped out by a single small oil spill. Food limitation
is another major threat to sea otters. The maximum density
of sea otters in a particular environment depends on the varying
availability of food in that environment. Other potential
threats to sea otter populations include disease, contamination
by pollutants, illegal kills, human disturbance, and a lack
of genetic diversity.
Knowledge Gaps
There are huge gaps in our knowledge of sea otter biology
and ecology. The last complete survey of the BC sea otter
population was done in 1995. There are no agreed upon methods
(comparable from year to year) of counting and monitoring
numbers, thus, there are no accurate coast-wide current population
figures, and trends in population numbers cannot be viewed
accurately from year to year. More research and study is needed
on the potential threats to the sea otter population. Even
though lack of genetic diversity, for example, can have serious
implications for the long-term survival of a species, the
genetic diversity of the BC population is unknown. Sources
of natural predation on the BC sea otter population are not
well documented. While the sea otter recovery strategy recognizes
the objective of protecting critical habitat, there is a lack
of knowledge about the necessary size and distribution of
such habitat. There is not enough information, for example,
about winter habitat (sea otters move seasonally within and
beyond their range). Options for oil spill protection need
to be further developed; threats from disease, pollution,
and human disturbance need to be more thoroughly investigated.
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