Extreme mobility of fur seals equal less concentrated pressure on penguins during breeding season
There was a strong El Nino this year, a climactic event that can dramatically change the weather patterns in the areas which we work. Compared to my previous (non El-Nino) field season, the mortality rate in chicks was considerable due to strong cold winds and large amounts of snow and sub-zero temperatures, leading to many adult penguins simply abandoning their nests and heading to sea. Unfortunately, this also included a number of our instrumented birds, resulting in the loss of the devices and the data they contained. However, we managed to describe Chinstrap and Adelie penguin foraging behavior during the breeding season for a second season. These data are critical in seeing how unpredictable climactic events such as El Nino impact breeding penguin foraging ecology, and in turn how these events must be considered when managing the krill fishery.
We had expected that the fur seals would conduct at-sea feeding trips in the waters around the South Orkneys, and had hoped to be able to see the overlap between the seals and penguins, to determine whether the seasonal influx of male fur seals competed with and put stress on penguins already having to work hard to feed hungry chicks. Some seals did, however a large proportion of the instrumented seals moved further south and west, travelling over 1,000km down the west Antarctic Peninsula as far as Adelaide Island. This extreme mobility of fur seals means that the ecological pressure exerted on krill stocks is spread across the entire region, overlapping with commercial fishing areas and penguin breeding colonies throughout the peninsula. The seal transmitters will continue to provide data for many months, allowing us to look in-depth at how adult male fur seals spend their time between breeding seasons.