Return of large fin whale feeding aggregations to historical whaling grounds in the Southern Ocean

Summary

Large-scale surveys in 2018-2019 documented the return of fin whales to historical feeding grounds around the Antarctic Peninsula after decades of absence following industrial whaling. The study estimated 7,909 fin whales in the survey area (density: 0.085 individuals/km²), with particularly high concentrations around Elephant Island (0.2123 individuals/km²). For the first time, researchers documented massive feeding aggregations of up to 150 whales - the largest ever filmed. This represents a promising sign of population recovery, with potential ecosystem benefits through the "whale pump" effect that could enhance carbon sequestration in the Southern Ocean.

Key Findings

First scientific documentation of large fin whale feeding aggregations (up to 150 individuals) at historical whaling grounds

Estimated 7,909 fin whales in Antarctic Peninsula region with average density of 0.085 individuals/km²

Highest densities found around Elephant Island hotspot (0.2123 individuals/km²)

Evidence of population recovery and return to ancestral feeding behaviors after near-extinction from whaling

Potential ecosystem restoration through whale nutrient recycling ("whale pump") enhancing carbon sequestration

Abstract

Fin whales (Balaenoptera physalus quoyi) of the Southern Hemisphere were brought to near extinction by twentieth century industrial whaling. For decades, they had all but disappeared from previously highly frequented feeding grounds in Antarctic waters. Our dedicated surveys now confirm their return to ancestral feeding grounds, gathering at the Antarctic Peninsula in large aggregations to feed. We report on the results of an abundance survey and present the first scientific documentation of large fin whale feeding aggregations at Elephant Island, Antarctica, including the first ever video documentation. We interpret high densities, re-establishment of historical behaviours and the return to ancestral feeding grounds as signs for a recovering population. Recovery of a large whale population has the potential to augment primary productivity at their feeding grounds through the effects of nutrient recycling, known as 'the whale pump'. The recovery of fin whales in that area could thus restore ecosystem functions crucial for atmospheric carbon regulation in the world's most important ocean region for the uptake of anthropogenic CO₂.

Published in

Scientific Reports

2022

Authors

Helena Herr, Sacha Viquerat, Fredi Devas, Abigail Lees, Lucy Wells, Bertie Gregory, Ted Giffords, Dan Beecham & Bettina Meyer

Institutions

Institute of Marine Ecosystem and Fishery Science, University of Hamburg Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research BBC Studios, Natural History Unit Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky University of Oldenburg Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg

Methods

AcousticBiological sampling DataField

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