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A population of humpback whales in the south Atlantic Ocean has been saved from the brink of extinction after decades of whaling.
While there has been little to celebrate ecologically in a world undergoing a climate emergency, there is at least some good news when it comes to the humpback whale. Researchers from the University of Washington have found that the creature’s population in the south Atlantic Ocean is increasing.
It is estimated that intense whaling in that part of the world in the early 1900s saw as many as 25,000 humpback whales caught and slaughtered, bringing their numbers to as low as 450. However, protections put in place in the 1960s and the introduction of a moratorium on commercial whaling in the 1980s by the International Whaling Commission has made a significant difference.
In a study published to Royal Society Open Science, the researchers showed that the western south Atlantic humpback (Megaptera novaeangliae) population has grown to 25,000, bringing it close to pre-whaling numbers.
They said this population growth is much quicker than previous studies had predicted. One of these studies charting populations between 2006 and 2015 suggested the population had only recovered to about 30pc of pre-exploitation numbers.
More productive than once thought
However, since that study, new data has come to light, providing more accurate information on catches – including struck-and-lost rates – and genetics and life-history.
One of the study’s co-authors, Grant Adams, said: “Accounting for pre-modern whaling and struck-and-lost rates where whales were shot or harpooned but escaped and later died, made us realise the population was more productive than we previously believed.”
The model developed by the researchers incorporates records from the whaling industry dating back to the early 20th century, which are then combined with air- and ship-based surveys, along with advanced modelling techniques.
The authors anticipate it can be used to determine population recovery in other species in more detail as well. Furthermore, the study analysed the impact of what a population growth of this scale would have on the wider ecosystem as the whales would compete with other predators, such as penguins and seals, for krill.
Lead author of the study, Alex Zerbini, said: “Long-term monitoring of populations is needed to understand how environmental changes affect animal populations.”
