By Dave Armstrong
22 Feb 2012
These Macquarie Island modern King Penguins (Aptenodytes patagonicus) amazing genetic diversity mirrors their ancestors, who were wiped out in many places; Credit: © John van den Hoff
Halfway house, between Australia and Antarctica, Macquarie Island was
used as a seal and penguin exploitation site for their "blubber."
Fortunately the two huge original colonies of King Penguins ended up as a
single tiny surviving colony due to the efforts of conservationists.
The King Penguin (
Aptenodytes patagonicus) is a great survivor,
unlike some species on Macquarie that become extinct quickly after
sealers took over the island in the 19th century.
After at least three spp. of fur seal, elephant seals were taken and
then an industry using the King Penguins in a "steam digester." Some
remnants of this industry can still be seen in parts of the island.
Fortunately, there was too much blood in the mix for fermenting to be
successful in this industry, so Royal Penguins were attacked instead.
This penguin oil industry confuses the modern ideas we have of "blubber"
but although less profitable than seals, penguin oil produced half a
litre per penguin. After 1919, petroleum oil became commercially
successful and the island reverted to a wild environment after 109 years
of total exploitation.
Cousin of the huge Emperor, the King Penguin is a magnificent diver
and has impressed us for much more than its oil. Even distant Edinburgh
Zoo has them as their mascot. The dive record is 343 metres, which for a
90cm bird at 16kg maximum, is remarkable. They were actually
exterminated on the Falklands and Heard Island, being circumpolar, but
with a 9.7 % growth in worldwide population, they have even managed to
re-colonise there. On Macquarie, the 1930 population of 3,400 animals
has recovered now to 70,000, with new colonies now dotted around the
east coast.( One colony is growing at a rate of 66% pa.)
Digesters used to harvest penguin oil on Macquarie Island; Credit: Shutterstock
Tim Heupink, John van den Hoff, and David Lambert present the penguins in the Royal Society Journal,
Biology Letters.
They work from Griffiths University, in Nathan, Australia and the
Australian Antarctic Division, The paper explains how ancient DNA from
sub-fossil sites, including the west coast, can be used to assess how
the modern recovery compares with pre-human populations and the drastic
anthropogenic pressure of the 19th century. Samples from 17 natural
carcasses' feet and 300mg of sub-fossil bone shavings were extracted and
purified before expert mitochondrial genome investigation produced the
data.
Radiocarbon-dating showed up the >1000 BP date of the
sub-fossils taken.
Credit: © Tim H. Heupink. This is Tim showing the semi-fossils from Mcquarie Island
Both ancient and modern populations show great genetic diversity. No
single ancestral type exists. Instead, the great population bottleneck
(presumably around1930) has left no trace of shared haplotypes
(genotypes) between the old and the new.
The King Penguin bottleneck diagram; Credit: © Tim H. Heupink
The ancient population of the Isthmus was the group that were made
extinct, leaving only the severely depleted Lusitania Bay colony with
little genetic diversity. The northern population probably came from the
remnants of the Lusitania Bay group. The ancient population from this
area is quite closely related to the present population and it shows a
similar genetic diversity. This study shows that the King Penguins in
this area have recovered their original genetic diversity in only 80
years since their mass exploitation for blubber oil. Comparing ancient
and modern DNA makes it possible to investigate the success of
conservation measures. In this case, putting an end to exploiting King
Penguins and controlling fishing and pests have clearly helped them to
recover so quickly."
And the final news on Macquarie - the endemic Royal Penguins show every sign of a similar recovery to that of the Kings.
source
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