Bubble net feeding is being brought to groups of humpback whales in Canadian waters by ‘immigrant whales’, which scientists think is crucial to the success of their recovering population.

The study published today in Proceedings of the Royal Society B shows that the recovery of humpback whales in the northeastern Pacific depends not only on population size, but on the spread of the culturally learned feeding behaviour across the whales’ social networks.  

Bubble-net feeding is when a group of whales work together to blow clouds of bubbles that gather their small fish prey schools into higher densities that they can then engulf together. It is a cooperative and highly social behaviour that requires whales to learn how to work in a group.

The feeding tactic has been seen for decades in the waters of Alaska. However, whales in Canadian waters either didn’t know or had lost the knowledge of the technique.  

The research was conducted in Gitga’at First Nation territory, within the Kitimat Fjord System of northern British Columbia, Canada – an area that has been stewarded by the Gitga’at First Nation for millennia and is known for its ecological and cultural importance. 

As the Canadian Pacific population of humpbacks has begun to recover from whaling, bubble netting has begun to spread and be adopted by those groups of whales too.

By analysing long-term social network data, the study shows that the spread of bubble netting behaviour is tightly linked to whale social structure, with knowledge passing through key individuals and groups

Researchers believe this bubble net feeding behaviour might have been introduced by immigrant whales from other areas, like humpbacks from Alaska.

Lead author from the University of St Andrews Dr Éadin O’Mahony, said: “Bubble-net feeding isn’t just a foraging trick, it’s a form of shared knowledge that strengthens the resilience of the entire population,”  

She added: “Species recovery isn’t just a numbers game, as the number of whales fluctuates, the distribution of cultural knowledge within the population may determine how well they adapt to change.

While the evolutionary importance of importing of new ideas is well known in human societies, this new study shows that it can also be important for whales.  The findings therefore emphasise the significance of integrating animal culture into marine management, particularly as human impacts on the ecosystem intensify.

Co Author Dr Luke Rendell, Reader in the School of Biology from the University of St Andrews, said: “This study reinforces our growing understanding that the flow and spread of information in animal societies is a vital part of their ability to thrive”

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