Ecosystems In Recovery – Whales
(Media release 1st September 2021)
Today the Government of South Georgia & the South Sandwich Islands are delighted to announce the release of a new stamp set to celebrate the recovering ecosystem of the Territory and in particular whales.
The waters around South Georgia & the South Sandwich Islands are safeguarded through a 1.24 million square kilometre Marine Protected Area (MPA). Biodiversity great and small is celebrated and conserved. However, this has not always been the case. During the 20th century over 170,000 whales were killed in South Georgia waters having an untold impact on the ecosystem as a whole. Whaling ended in South Georgia in the 1960s, but whales were rarely seen on this important feeding ground for the next 40 years.
More recently, anecdotal accounts indicated that whale populations were increasing and the ecosystem was recovering. Running from 2017-2021, a project to estimate the recovery status, abundance, diversity, health and habitat use of whales on their South Georgia feeding grounds was established. The South Georgia Wild Water Whales project was led by the British Antarctic Survey in collaboration with research experts around the world.
The project used a range of scientific approaches, including conducting visual and acoustic surveys of whales, collecting photo-identifications and skin samples for genetic identification, deploying transmitters on whales to track their movements, collecting samples of whale breath by drone, and measuring whale body condition using overhead images. The project also benefitted from the many citizen scientists who took photo-identifications of whales at South Georgia and submitted them to www.happywhale.com, a global repository of whale photographs which are regularly matched with researcher catalogues.
This series of stamps celebrates the recovery of whale populations around South Georgia and showcases some of the fantastic scientific research which is helping us to better understand, and further protect them.
55p – Southern right whale
South Georgia is thought to be a key summer feeding ground for the southern right whale. To examine how they use this feeding habitat, two southern right whales were tagged with transmitters in austral summer 2020, and their movements tracked by satellite for the following months. While one whale (a female, blue track) travelled to the ice edge during summer and autumn, the second animal (a male, green track) remained in South Georgia coastal waters for six months, mostly at the western edge of the island, migrating north from South Georgia towards warm waters in winter (July). These patterns help to highlight which areas are particularly important for feeding right whales and show individual contrasts between whales and their use of high latitude habitat over summer and autumn.
70p – Humpback whale
Over six hundred humpback whales were seen during a whale survey around South Georgia in 2020. These sightings are shown as red dots on the map, with the size of the dot indicating the size of the group. This information was used to predict areas of high humpback whale density around the island. High intensity purple shading indicates high densities of whales. Understanding the density and distribution of whales is important to enable us to manage human activities such as shipping that may pose a risk to whales.
80p – Antarctic blue whale
The underwater vocalisations of blue whales were recorded using sonobuoys: acoustic devices which enable whale calls to be detected and the direction they come from to be measured. These data were collected during expeditions to South Georgia in 2017, 2018 and 2020. The calls and their bearings were analysed to determine the likely locations of the whales, and these were plotted on a map. In 2017, vocalising blue whales were all detected in deep water, both to the southwest of the island and to the north of the island (shown in yellow). In 2018, blue whales were detected on the continental shelf off the northern coast (shown in green). In 2020, sonobuoys were deployed around the entire island of South Georgia. In this year, blue whales were detected to the west of South Georgia, near to Shag Rocks (shown in red), along the northern shelf, and to the southeast of the island. These acoustic data show blue whale detections around the island are increasing, this pattern is also reflected in the number of visual sightings of blue whales, which have been rising in recent years as populations recover from industrial whaling.
First Day Cover – Humpback whale key feeding habitats
Satellite-based tracking of humpback whales feeding in South Georgia and South Sandwich Islands waters was used to model their likely distribution within the MPA. By examining whale distribution between October and July over a 17-year period, these models show that humpback whales have particular hotspots over the South Sandwich Trench, to the west of the South Sandwich Islands, and immediately over the shelf of mainland South Georgia (yellow areas of high habitat use probability). Encouragingly, this shows that the current footprint of the MPA and its management measures afford a significant degree of protection of the feeding grounds of migratory humpback whales.
The Wild Water Whales project was funded by EU BEST, Darwin PLUS, South Georgia Heritage Trust, the Friends of South Georgia Island and the World Wildlife Fund, with logistical support from the Government of South Georgia & the South Sandwich Islands. More project information can be found here: https://www.bas.ac.uk/project/south-georgia-right-whale-project/