Environmental impact – South Georgia Museum

Science projects take many years to plan and fundraise for. Scientists work long hours in the field, sometimes in difficult conditions. Here the Hungry Humpbacks team watch on as they fly their drone. *© BAS Hungry Humpbacks, Amy Kennedy*

WHY SHOULD WE STUDY WHALES?

Scientists have discovered that whales are important in the fight against climate change. Their enormous bodies can store tonnes of carbon. When they die, carbon gets trapped on the bottom of the seafloor, as the carcass sinks to the depths. As it decomposes it provides nutrients for deep-sea creatures. Whale excrement is also vital for oceanic biodiversity. It fertilises the seas and encourages phytoplankton growth – the foundation of the marine food pyramid. The phytoplankton blooms from the iron rich faeces, in turn sequestering huge amounts of carbon.

Humpback whales migrate annually between breeding and feeding grounds. They feed around South Georgia and the South Sandwich Islands until autumn, when they return to coastal Brazil to breed in winter. © Bamford, C.C.G. et al. (2022) ‘Humpback whale (Megaptera novaeangliae) distribution and movements in the vicinity of South Georgia and the South Sandwich Islands Marine Protected Area’, Deep Sea Research Part II: Topical Studies in Oceanography, 198, p. 105074.

The remote and harsh nature of the Antarctic region has proved difficult in the monitoring and research of whales. Attempts were made to assess the post-whaling population of large cetaceans around South Georgia using observations between 1979 and 1998. Data were compiled from a single cruise in 1997, in addition to long-term records from both mariner sightings and observations from the science base on Bird Island. This research revealed that encounters of all species were still considered rare, an indicator that populations were still yet to recover.

Although opportunistic sighting data is still often used to study whale populations, research has progressed since, utilising a suite of modern technology to monitor health and habitat use.

The British Antarctic Survey (BAS) has spent decades studying our polar regions. Since 2001, BAS has operated the base at King Edward Point on behalf of the Government of South Georgia. Recently scientists have gathered acoustic data of whales from Cumberland Bay as well as drone surveys, skin samples and satellite tagging. Continued study allows us to see migration, reproduction and feeding patterns of whales. These projects are crucial to learn more about the lives of whales.

Humpback Whales can feed together using a technique called “bubble-net” feeding. Here whales use their blowholes to expel in spiral patterns under schools of fish and crustaceans. This stuns their prey, allowing them to be gulped by the whales.Image: © Christin Khan, NOAA / NEFSC

Studying whales also has practical applications. Data has a direct impact on the ecosystem around the island, informing krill fishery quotas. The Hungry Humpbacks project, run by BAS between 2023 –2025, measured the seasonal foraging of Humpback Whales in South Georgia’s waters. Using drones and by attempting to get skin samples, they analysed the body condition of the whales that were spotted.

The South Georgia marine ecosystem is globally recognised as a biodiversity hotspot. Containing a high biomass of Antarctic Krill (Euphausia superba), a key food source for seals, whales, seabirds and fish. There is evidence that krill distribution has shifted over the last 90 years, with densities declining around South Georgia. The shift in krill distribution could be particularly impactful for larger baleen whale species which consume large volumes of krill.

Humpbacks are one of the many species who consume krill. By tracking Humpback whale foraging patterns, we can ensure krill fishing is limited. We must learn from past failings, if we take from marine environments, we need to do it in a balanced way.

All the scientific data will help inform policy to better protect whales in the South Atlantic and the Southern Ocean, so that populations can recover as much as possible.

During fieldwork for the Hungry Humpback project in 2024, the team caught footage of a Blue Whale and her calf in South Georgia. Viewing them from above allows scientists to measure their body condition, this information is used to inform krill quotas. © BAS Hungry humpbacks, Fredrik Christiansen

Whale spotted as part of BAS research, with the glaciers of South Georgia in the distance. *Image: © British Antarctic Survey*

Are the whale populations recovering?

Whales are still in danger. Although whale populations are beginning to recover from the whaling industry, they still need protection. They are at risk from climate change, sound pollution, and vessel strikes.

During the 1970s many conservation organisations realised that unless action was taken many of the great whales would soon become extinct. In 1972, the United Nations General Assembly and the International Union for the Conservation of Nature (IUCN) proposed a ten-year moratorium on whaling but the International Whaling Commission (IWC) rejected it. Three years later the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITIES) gave full protection to several species including the Grey, Blue, Southern Right and Humpback Whales. But the hunting of other species continued until 1986 when the IWC finally responded to international pressure and instituted a limitation on commercial whaling.

Humpback whale spotted as part of BAS research, with South Georgia in the distance. *Image: © British Antarctic Survey*

Despite whales continuing to face many challenges in their changing environments, there are positive stories emerging about improving populations. Humpbacks are estimated to be close to pre-whaling levels and are no longer endangered, with the recent BAS fieldwork reporting 790 animals during a 21-day survey in January 2020. Others like Blue and Fin Whales are still very much recovering.

Following the cessation of industrial whaling, the Antarctic Blue Whale was classed on the IUCN Red List as Critically Endangered. They are estimated to be at only 2.5% of the pre-industrial exploitation 1926 level. Scientific estimates project that a plausible rate of natural increase for Antarctic Blue Whales is 4.2% pa. In 2020 a team of BAS scientists, undertaking surveys from South Georgia, reported an “unprecedented” 55 sightings of Antarctic Blue Whales. This is a positive sign, suggesting the endangered Blue Whale is making a return to its native feeding grounds.