Genetic analysis of Antarctic fur seals, alongside decades of in-depth monitoring, has provided unique insights into the effect of climate change on a population of top-predators. Published in Nature this week, the findings show that the seals have significantly altered in accordance with changes in food availability that are associated with climate conditions. Despite a shift in the population towards 'fitter' individuals, this fitness is not passing down through generations, leaving the population in decline.
Environmental change is expected to affect many species and biological systems throughout the world. To understand these changes long-term monitoring is required. The British Antarctic Survey's unique Long Term Monitoring and Survey programme has given researchers a rare opportunity to explore how fur seal life histories have changed over time in relation to the climate and food availability.
Researchers from the British Antarctic Survey and Bielefeld University in Germany analysed data gathered from as far back as 1981 to assess changes over generations of female fur seals on South Georgia, in the South Atlantic Ocean.
Lead author, Dr Jaume Forcada from the British Antarctic Survey explains:
"Compared with 20 years ago, we can see that female fur seals are now born with a lower weight, those that survive and return to breed tend to be the bigger ones and they have their first pup later in life than they used to. Such changes are typically associated with food stress.
"An important food source for the seals is Antarctic krill. Decades of data collected at South Georgia show how changes in the seal population have occurred over time with changes in krill availability. Even if krill is very abundant, environmental variation determines its availability in the seals' feeding grounds. This environmental variation is driven by the climate which impacts local atmospheric, sea ice and oceanographic conditions.
|Contact: Paul Seagrove|
British Antarctic Survey