Emily Wardrop

For hundreds of years, all different species of whales have been hunted for their dense blubber, oil and meat. During industrialisation, the numbers of whales killed increased rapidly and populations fell dramatically to match - so much so that blue whales haven’t been seen in the Antarctic waters for 50 years. That is, until February 2020...

Large-scale industrial whaling of the early 20th century decimated whale populations across the world. South Georgia Island, situated North of the Antarctic, was once a region densely populated with large whales. Knowledge of the productivity catapulted blue whales into the firing line of a fury of whaling expeditions from 1904. This caused the slaughter of more than 40,000 whales by 1970. As a result, resident blue whale populations were significantly reduced and became absent from all surveys hereafter. 

Ambitions in Antarctica

Blue whales follow migratory routes that facilitate their reproductive cycle. In the winter, whales generally occupy warmer, equatorial waters to give birth. In the summer they migrate to the cooler and more productive polar regions to feed on krill. In Antarctic waters around South Georgia krill abundance is particularly dense during the summer as a result of seasonal upwelling, which stimulates nutrient enrichment. Due to the nutrient-rich environment, large abundances of blue whales were reported around South Georgia at the start of the 20th century. Knowledge of this whale hotspot encouraged the congregation of whaling fleets to the island and led to the establishment of seven whaling stations by 1912.

Decimation of South Georgia

By the 1920’s, easily accessible whales that inhabited coastal waters around South Georgia, including humpbacks and southern rights had declined significantly. The scarcity of whales by the shore triggered the rapid expansion of hunting to pelagic whaling, and out on the open ocean - it was a whaling free-for-all. Further development increased the speed of vessels and efficiency of weapons, which led to a shift in focus to larger, faster species like blue whales. 

Intense whaling rapidly decimated blue whale populations. Between 1904 and 1971, a total of 42,698 blue whales were killed. However signs of stock collapse became evident in the early 1930’s and blue whales were soon reduced to secondary target species. In fact, only 1,800 (4%) whales were killed after 1936 because there were so few individuals, that fishers only hunted them upon random encounters.

A ban on whaling around South Georgia was implemented in 1965 in an attempt to save the whales from total collapse. However, for the past five decades an unfortunately low number of blue whales have been sighted in these waters, with many researchers believing that the population would never recover.

Bringing Blue back

During a polar expedition in February 2020, researchers from the British Antarctic Survey (BAS) made an incredible sighting: they recorded 58 blue whales off the coast of South Georgia Island. As of yet, little is known about the reason for their return, or what this could mean for conservation efforts around the island. Currently South Georgia waters are a designated Marine Protected Area (MPA). However, recent advances in shipping and tourism mean that there is more traffic present in these waters. There are several studies addressing the impacts of noise pollution on marine mammal health and ship strikes cause a large number of whale mortalities a year. 

A significant amount of research is still needed into these new populations to determine the dynamics and make adjustments to the protection efforts already in place. However, it is very exciting to see large numbers of individuals inhabiting these Antarctic waters after 50 years of absence. There may be hope for big Blue yet. 

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