Southern right whales, once pushed to the brink of extinction, now face new challenges. After decades of recovery from commercial whaling, these magnificent creatures are struggling with declining breeding rates, mainly due to climate change.
Dr. Claire Charlton, a marine biologist, notes that instead of having a calf every three years, these whales are now giving birth every four to five years. This change has been observed since 2017, raising alarms about their future and the health of the Southern Ocean.
For over 30 years, researchers have used unique markings on southern right whales, called callosities, to track their movements and breeding patterns. These studies take place primarily in the Great Australian Bight, where the whales come each winter to mate and socialize. Dr. Charlton describes them as “magnificent animals,” capable of living up to 150 years.
According to a recent study published in Scientific Reports, the shift in breeding frequency relates to warming ocean temperatures and melting sea ice. The study found a direct connection between the number of calves born and environmental factors like sea ice extent and marine heatwaves. This correlation is concerning for the survival of not just southern right whales but other marine animals that depend on similar ecosystems.
Globally, similar trends among southern right whales have been reported, suggesting that regional problems mirror broader climate issues. Vanessa Pirotta, a whale scientist, emphasizes the importance of long-term data to understand these animals’ adaptations to changing conditions.
Dr. Peter Corkeron, a marine ecologist, shared that as conditions worsen, female whales tend to have fewer calves. He explains that balancing the demands of motherhood with the need to survive is crucial for these mammals.
Since commercial whaling ended in Australia in 1979, the population rebounded to an estimated 2,346 to 3,940 individuals. This is still only 16% to 26% of their numbers before whaling. These whales play a critical role in their ecosystem, foraging on zooplankton and maintaining ocean health.
In light of these findings, it’s clear that climate change represents a significant threat to southern right whales and many other marine species. Awareness and action are urgently needed to protect these whales as part of broader conservation efforts.
