A commitment to the future

MEET THE WHALES OF SOUTH GEORGIA

Whales don’t recognise national boundaries, but they do have core geographies and habitats where they feed, rest, mate and bring up their young. The Southern Ocean, surrounding the Antarctic continent, is the world’s largest marine mammal feeding ground. South Georgia is a hot spot for whales due to the large numbers of krill. As a result, it is home to a varied assemblage of whales, with certain species found in the cold waters all year round.

Illustrations: Kim Robertson, 1998. South Georgia Museum.

Whales belong to a diverse group of specialised aquatic mammals called cetaceans. They can be divided into two broad groups: toothed whales and baleen whales. Toothed whales possess teeth and use echolocation to find their prey, feeding on the likes of fish, squid and other large animals. Porpoises, dolphins and the Sperm Whale all belong to this group and rely on the Antarctic region throughout the year. Instead of teeth, baleen whales have specialised baleen plates formed of keratin, the same substance found in our hair and fingernails. These plates act as a sieve, filtering small prey from the water. Examples of baleen whales include the Humpback Whale, Blue Whale and Southern Right Whale.

Baleen whales are highly migratory, with most species needing to travel vast distances seasonally to feed and breed. The majority of these whales eat krill, a plankton found in very cold waters. In the Austral summer, many baleen whales migrate to the Southern Ocean to feed on the abundant Antarctic Krill source. However, these cold conditions are not suitable for whales to give birth. Calves have much less insulation, born without the protective blubber layer under their skin. So, whales will travel long distances north, to the coasts of South America, in pursuit of warmer, shallower waters for calving and mating.

Cetaceans have a wide range of sizes, from porpoises, at little over a metre in length, to the largest animal to ever live – the Blue Whale. Processed at Grytviken whaling station in 1912, the longest Blue Whale recorded was a 34.1m female. South Georgia again holds the record for the heaviest Blue Whale, with a 173 tonne female taken in 1947. However, the accuracy of both measurements is disputed, with the longest scientifically measured Blue Whale placed at 29.9m and the generally accepted range of body weights between 73-136 tonnes.

Humpback whale in South Georgia's waters in 2024. © British Antarctic Survey – Wild Water Whales / Hungry Humpbacks project.

Listening to the whales

Sound waves travel faster and further through water than they do through air. The whale sounds are recorded on hydrophones – devices that detect sound under-water. These devices can be moored on fixed spots or detectors can be used during fieldwork.

Eavesdropping on whales in South Georgia’s waters can tell us what they are doing, for example, feeding or socialising. We can also learn a little about where they are, by using acoustic detectors that can take a bearing of where the calls are coming from. We must remember that not all whales are noisy, so the absence of sounds doesn’t always mean an absence of whales.

The British Antarctic Survey have been listening for whales in South Georgia’s waters since 2006. Working with the Scottish Association for Marine Science they have discovered that some species like Humpback and Southern Right Whales are here both in summer and winter. Antarctic Blue and Fin Whales are only calling from further offshore in winter. Cetacean calls vary greatly in their pitch – some too high for humans to hear, and some too low. Some of these sounds have been sped up by up to 10 times to make them detectable to the human ear.

Listen below to hear some examples of whales that visit South Georgia’s waters.

Antarctic Blue Whale D-Calls – Brian Miller, Australian Antarctic Division

Antarctic blue whale D-calls recorded on using DIFAR sonobuoys during the 2013 Antarctic Blue Whale Voyage (from FV Amaltel Explorer). Starting dates and time of recordings 2013-03-07 22:56 & 2013-03-08 01:00. These recordings have been low-pass filtered at 250 Hz to emphasize the D-calls and attenuate other sounds. NB: The harmonics in these calls make them more audible than most d-calls, but are likely due to distortion from exceeding the maximum levels of the recording chain. Recorded and curated by Brian Miller, Australian Antarctic Division. Credit: Brian Miller, Australian Antarctic Division.

Antarctic Blue Whale Z-Call – Brian Miller, Australian Antarctic Division

Antarctic blue whale song (z-calls) recorded on AAD moored acoustic recorder along the resupply route to Casey Station in 2014. This file has been sped up by a factor of 8 to make it audible (playback will be 8 times faster than the original recording). Dataset: Casey2014. Starting date and time of recording 2014-04-20 18:07:28. Recorded and curated by Brian Miller, Australian Antarctic Division.

Humpback Whale – Brian Miller, Australian Antarctic Division

Humpback whale song recorded on AAD moored acoustic recorder along the resupply route to Mawson Station in 2015. Dataset: Kerguelen2015. Starting date and time of recording 2015-05-09 16:23:56. Recorded and curated by Brian Miller, Australian Antarctic Division.

What you can do to help

The marine story is complex. Biodiversity is essential for all who co-habit the Antarctic environment. It is key for balancing the climate and every species has its role to play. When one is removed, this can have knock-on effects to other species, and eventually to the ocean itself as a climate regulator.

The waters around South Georgia and the South Sandwich Islands are protected by a 1.24 million km2 Marine Protected Area. Regulated fisheries are balanced with breeding and foraging wildlife seasons. Trawl fishing is prohibited and krill fishing limited to certain areas in winter months. When organisations and people work together, we can continue to protect whales, and ensure we safeguard biodiversity in our oceans. We must maintain science and conservation efforts to ensure we continue our co-existence with these colossal creatures.

The Happywhale project uses ‘citizen science’ to help track whales globally and inform policy making. In 2019, based on information from the project, IAATO implemented operating procedures for boats near whales to lower the risk of ship strikes in Antarctica. *Image: © Lewnwdc77*

Your visit to this online exhibition gives you the opportunity to be an ambassador for whales and for South Georgia. Happywhale has been using photo-identification to track the movement of whales, since 2015. This project provides a digital platform where people can submit photos and details of marine mammal encounters. By recording all sightings of whales, you can make a difference and provide crucial information about whale populations.

You can help whale science around South Georgia and beyond by submitting any whale sighting data and photographs to happywhale.com. The team at Happywhale use the photographs to identify individual whales from their unique markings, and can then track the whales as they travel around the globe. You can choose to be notified on any future sightings, so you can follow your whale’s journey.

Visit the Happywhale Project

Photograph of whales and birds captured during science projects funded by South Georgia Heritage Trust. *Image: © Phil Tempest*

Join us in making a difference

If you would like to support conservation efforts which impact whales here are some suggestions. If we all act it can make a difference.

Support whale safe fishing
Report marine mammal harassment
Donate to charities who support marine mammals, such as South Georgia Heritage Trust
Bring awareness to the issues that whales face
Support climate change groups
Strive for more ethical consumption

Today, the legacy of industrial whaling informs our approach to marine conservation. We are dedicated to promoting awareness, fostering sustainable practices, and advocating for policies that protect marine ecosystems. By understanding the past, we can make informed decisions that support the recovery of whale populations and the future health of our oceans.

Pharos SG, the South Georgia Government’s Fishery Patrol Vessel plays a key role in conservation around the island. It does so by carrying out surveys with scientists on board and bringing supplies and personnel to South Georgia. © South Georgia Museum, Jayne Pierce