bouncing back from the brink of
extinction is good news but the fur
seals on South Georgia are now facing
danger as a result of overcrowding which
could threaten the future of the species
once again Antarctica a bleak beautiful
landscape for over 60 years fur seals
have been studied here by the British
Antarctic Survey and the seals
remarkable story reflects our changing
environment on bird Island station in
South Georgia scientists are surrounded
by seals they are everywhere but let’s
go back a bit how did we get here to
this enormous colony if we could see
this beach in the 1800s
we’d be lucky to see one seal 1.2
million were killed for their pelts in
South Georgia alone seal hunting was the
first industry in the Antarctic and from
the late 1700s and throughout the 1800s
fur seals on the island of South Georgia
were hunted intensively after 30 years
fur seals were hard to find the
population plummeted from 1 million to
fewer than 400 individuals by the 1900’s
fur seals were on the verge of
extinction remarkably they bounced back
How did we get here
a small breeding colony was discovered
on nearby Bird Island in the 1930s
in the 1950s and 60s up to 10,000 seal
pups were being born a year and by 1976
numbers were thought to have reached a
hundred thousand
in the 90s more and more seals were
being fined further away from South
Georgia and its surrounding islands in
2015 the population was estimated at
between five and seven and a half
million 95 percent of the world’s
population of Antarctic fur seals now
inhabit South Georgia three times the
pre hunting number an animal the size of
a fur seal recovering its population
numbers that quickly is unprecedented
and shows what a remarkable animal these
days so what happened seal hunting
largely stopped and an increase in whale
hunting meant less competition for krill
the seals main food source seals are
very efficient predators they produce an
offspring a year and living in an area
abundant with food meant their numbers
rocketed the researchers have discovered
that female fur seals are being born
with a lower birth weight only the
larger female fur seals are surviving
and returning to breed they’re also
having their first pups
later in life all this indicates that
the females are dealing with food stress
there’s just too much competition these
successful females are more likely to
have high levels of genetic variation
which makes them more resilient
the female will seek out a genetically
different male to produce stronger
offspring when the sales were close to
extinction
they faced a genetic bottleneck but this
act of choice of a genetically different
partner may have helped the fur seal
population to explode with such vigor
however the fact that currently it’s
only these super females that are
managing to breed demonstrates the
stress the population is under
overcrowding has led to intense
competition and stress amongst the seals
Overcrowding and stress
bull seals that way on average 126
kilograms and are around 2 meters in
length are territorial and aggressive
fighting males can often trample fragile
pups and severely injure them such
aggressive behavior from breeding males
can disrupt mother pup bonding and lead
to pup abandonment hungry pups are known
to try and feed from any female and
risky mood as females have been seen to
attack pups that aren’t their own
starvation and skull injury are more
likely to kill seal pups than anything
else pups are getting smaller as food
competition means mothers have less milk
we all know stress isn’t good but how is
this affecting these young pups stress
can lead to the production of
corticosteroids increased heart rate and
the production of adrenaline in animals
stress can deplete the energy of a young
pup who needs all its reserves to grow
and develop lack of rest in a calm
environment damages their ability to
regulate their body temperature and
build up the strength they’ll need to
survive stress can even reduce the
periods of feeding and damage the mother
pup bond
their time on land is when they build up
reserves so overcrowding and a stressful
environment could lead to malnutrition
starvation or death overcrowding is not
the only challenge facing South
Georgia’s fur seals climate change is
also having an impact krill forms the
majority of Antarctic fur seal diets the
availability of krill is vital in
determining the survival of the fur seal
population the Antarctic circumpolar
current for ACC channel’s nutrient-rich
waters towards South Georgia how much
krill reaches the island depends on the
ACC krill numbers could be reduced by
ocean acidification and scientists are
already noticing changes in weather that
mean fewer krill in the ACC being swept
up to South Georgia the peninsula region
is one of the most rapidly warming areas
of the planet and less sea ice will have
an effect on krill the fur seals in
South Georgia are acting as a warning
for global challenges large animals that
feed in a marine environment give us a
very clear picture of what is happening
to our sea life after surviving near
extinction due to hunting only time will
tell if the fur seals of South Georgia
can survive another man-made threat
[Music]
