Humpback whales thrived during pandemic pause, study finds

A whale pod off Australia's east coast. Credit: Jake Linsky.

Researchers from the University of Queensland have discovered that migrating humpback whales off Australia’s east coast experienced less stress during the first year of the COVID-19 pandemic.

This study, published in Marine Environmental Research, was led by Dr. Jake Linsky from UQ’s School of the Environment.

The research, conducted at Moreton Bay Research Station, aimed to assess the health of humpback whales during a period of significant changes in human activity.

“We used drone photographs and blubber samples to evaluate the health of eastern Australian humpback whales in the waters off Minjerribah—North Stradbroke Island—during their migration in 2020 and 2021,” explained Dr. Linsky.

The team utilized drone images to measure the whales’ size and body condition, which are important indicators of the energy they store for their long annual migration and breeding period.

“We also used small boats to get close to the whales and collect tiny samples of skin and blubber,” said Dr. Linsky. “These samples were then analyzed for hormones and gene expressions related to stress, energy reserves, and immune health.”

The results showed that cortisol levels, a stress hormone, were significantly lower in 2021 compared to 2020. This suggests a decrease in environmental stressors during that time.

Dr. Linsky noted that several factors likely contributed to these findings, including a shift to La Niña climate conditions and significant reductions in human activity due to the pandemic. Additionally, the gene expression results hinted that whales might have been responding to a decrease in pollutants in their feeding waters.

“Previous studies have observed similar changes in stress hormones in whales on the other side of the Antarctic continent. Our findings support the idea that these changes occurred throughout the Southern Ocean,” said Dr. Linsky.

The study highlights the importance of migratory whales as indicators of the health of Antarctic marine ecosystems. Eastern Australian humpback whales have shown a remarkable ability to adapt to environmental changes, but the research emphasizes the need to mitigate human impacts to ensure their continued well-being.

“By monitoring and protecting humpback whales off Australia’s east coast, we can help maintain their health and stability,” Dr. Linsky stated. “This also offers valuable insights into how we might conserve other struggling whale populations.”

Overall, the study demonstrates the positive impact of reduced human activity on whale health and underscores the importance of ongoing conservation efforts to support these magnificent creatures in our rapidly changing oceans.