Insights into the subantarctic
SEA lion mortality has improved slightly on the Auckland Islands but it remains high on Campbell Island, research has found.
The largest and most ambitious marine fieldwork season ever undertaken in the New Zealand subantarctic is providing valuable insights on the vulnerable native species living there.
The Department of Conservation (Doc) has wrapped up a bumper summer field season where for the first time rangers, scientists, independent researchers and other staff were stationed on all five of the remote subantarctic island groups — Bounty Island, Antipodes Island, Snares Island, Auckland Islands and Campbell Island.
Doc marine bycatch and threats manager Kris Ramm said much of the work focused on filling knowledge gaps for species, as well as maintaining and fixing important field infrastructure.
“The subantarctic islands are remote and hard to reach; undertaking work down there requires a lot of careful coordination. Things such as the Covid19 pandemic, Cyclone Gabrielle and other external factors have all impacted our work programme on the islands in recent years, so we’re thrilled to have been able to complete successful trips to each of these islands this year,” he said.
New Zealand’s subantarctic islands represent one of the last great wildernesses anywhere in the world and are located hundreds of kilometres to the south and southeast of the South Island.
They are home to a range of rare species, such as Antipodean and Gibson’s albatross, which breed nowhere else on Earth. The islands are managed by Doc as national nature reserves, the highest possible conservation status.
They have also been honoured with World Heritage status, meaning they represent the best of the world’s natural heritage and rate alongside the Grand Canyon and Mount Everest.
The research and monitoring programme will help us to understand the health of vulnerable native species such as yelloweyed penguin, New Zealand sea lion, Gibson’s and Antipodean albatross, and other seabirds.
“For many of these species, the subantarctic region represents their last stronghold. It’s important we understand the threats and challenges they face so we can better focus our efforts.
“Some of the research programmes, such as the Antipodean albatross work, have been going on for decades.’’ While it will take some time for the full suite of monitoring data to be analysed from the season, so far there are some trends emerging, he said.
“The number of sea lion pups born on the Auckland Islands had a slight increase from the extraordinarily low year last year, but not to the extent we would have expected. On Campbell Island, pup mortality continues to be high, with up to 89% of sea lions dying in their first few weeks of life. While the precise reasons for this remain unclear, many pups on Campbell Island appear to die of a combination of exposure and starvation.”
New Zealand sea lion pup production at the Auckland Islands in 2022/23 had dropped by 24% from the year before and research was being done to find out why.
The number of southern royal albatross also appeared to have declined. Teams were still working through exact population estimates.
Teams were getting samples of wildlife health, which the University of Otago was testing for pathogens, including avian influenza viruses.