King penguin with chick.
Three squawks for conservation! After New Zealand businessman Joseph Hatch boiled down 3 million Macquarie Island king penguins for their blubber, public outrage helped make the island a wildlife sanctuary in 1933. The king penguins then flourished undisturbed, growing from the decimated population of 3,400 to half a million today. Those raw numbers look good, but to gauge the population’s viability, scientists needed to find out a little more. A new study has found that the population has also recovered to pre-slaughter levels of genetic diversity, just 80 years after their near-extinction.
Population bottlenecks like the one caused by Hatch’s steam digester mean not only fewer individuals but also less diversity in the gene pool. This makes it difficult for the population to adapt to any stresses—a disease, for example, that can wipe out the remaining population if everyone has the same immune system.
To compare pre- and post-bottleneck genetic diversity, the researchers sequenced DNA from 1,000-year-old penguin bones on the island. The ancient DNA samples had similar levels of diversity as modern samples from the foot of living penguins. The researchers were surprised by how the population had recovered and saw this as a testament to conservation efforts.