The recovery of humpback whale populations: A cause for hope in conservation

Saving our seas: the recovery of critically endangered whales

Amy Wallis 
Artist & Editor: Ben Freeman 

With a climate emergency declared in the UK and talks of us entering a sixth global mass extinction, it often feels that any action now is too little, too late. Most media coverage of conservation focusses on the decline of biodiversity and the failures of conservation efforts, so far. But there are real cases of conservation efforts and species management leading to the recovery of species on the brink. A striking example of this can be seen in many baleen whale species. The practice of whaling grew massively from the 17th to 20th centuries, as demand for whale oil and baleen skyrocketed. Almost three million were killed in the 20th century alone. As a result, whale populations crashed. While some, like the North Pacific right whale, Eubalaena japonica, remain in the low hundreds, many species have shown remarkable recoveries. 

One recent success story is the recovery of the humpback whale, Megaptera novaeangliae. The humpback whale is, arguably, the best studied baleen whale, and studies indicate a significant global population recovery. A 2019 study estimated the western South Atlantic population to have rebounded, from only 450 individuals, to 93% of its pre-exploitation size. According to the IUCN red list, all breeding populations have recovered to pre-1942 levels, and the species is now listed as ‘Least Concern’. The fact that a population can recover from such low levels shows us that, it is not too late to address the current biodiversity crisis. 

The recovery of humpback whales is due to a managed reduction in exploitation and conservation management. A major driver of whale recoveries was the banning of commercial whaling by the International Whaling Commission in 1986. While commercial whaling has continued since the IWC ban, notably by Iceland, Norway and Japan, it is on a far smaller scale and generally targets less endangered species. Careful management and monitoring have also facilitated the recovery of the humpback whale. The habitats and breeding sites of the species have been well studied, and protected in many national and international agreements. For example, the US government set a comprehensive recovery plan for the species in their waters, in as early as 1991. This management shows the effectiveness of international agreements and governmental legislation designed to protect species. We should push for further international meetings to bring about environmental protection and conservation, even when they seem to foster little action. 

The resurgence of the humpback whale is not all good news; it has the potential to harm already struggling ecosystems. As large predators, a healthy humpback whale population consumes lot of food – in this case, krill. This may have knock-on impacts on other krill-dependant organisms. Furthermore, there is evidence that the distribution of krill is shrinking with increasing ocean temperatures, which may further increase the impact of humpback whales on the community. While this needs to be monitored, there is no reason to believe the return of the humpback will have serious negative effects. It is important that both researchers, policy makers and the public take note of the successful return of humpback whales and other whale species. Research has shown that a message of hope is needed for conservation to be successful; we need to hear success stories to balance the bad news and empower people to help enact change.  

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