Life under the sea is filled with simple pleasures, free from the hustle and bustle of human life. Who would have thought that, amid the stress of the COVID-19 pandemic, there would be an upside to lockdowns for humpback whales?
A team from the University of Queensland, led by the curious Dr Jake Linsky, has made a fascinating discovery: the calming effect it has on migrating humpback whales off the east coast of Australia.
Dr Linsky, from UQ’s School of Environment, studies the health of the species from Moreton Bay Research Station. When he’s not locked in a lab, he’s taking drone photos and collecting blubber samples to gauge the health of these free-ranging cetaceans.
“Control” of whales
With their remarkable recovery from historic whaling, the health of these Australian humpbacks is a topic of great interest, and the team is excited about using cutting-edge tools to monitor their welfare.
“We used drone photography and blubber samples to assess the health of eastern Australian humpback whales in the waters off Minjerribah – North Stradbroke Island – during their migration in 2020 and 2021,” Dr Linsky said.
“This population has had one of the most successful recoveries since historic whaling, so we wanted to use the latest tools to monitor their health.”
Deciphering the Stress Levels of Humpback Whales
“We also used small boats to approach the whales and collect small samples of the skin and blubber from the whales’ flanks,” Dr. Linsky added.
Once collected, these sludge samples were examined for hormones and gene expressions related to stress, energy reserves, and immune health. One striking revelation was the significantly lower concentrations of cortisol—a stress hormone—in 2021 compared to 2020.
Reduction of environmental stressors
This drop in cortisol levels indicates a reduction in environmental stressors throughout the year. How did this happen?
Dr. Linsky attributes the change to several factors, including climate change and the dramatic shift in human activities during the pandemic.
“Several things happened during this period that likely contributed to our findings, including a shift in the climate to La Niña and dramatic changes in human activity during the pandemic.”
“Our gene expression results also provide a further hypothesis, namely that the whales may have been responding to a decrease in pollutants in their remote feeding waters.”
“Previous studies have found 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.”
Implications for conservation policy
The findings of Dr. Linsky’s research have important implications for conservation policies aimed at protecting humpback whales and other marine animals.
The observed decline in cortisol levels during periods of reduced human activity supports the argument for establishing marine protected areas and imposing stricter regulations on maritime traffic and pollution.
By minimizing human-induced stressors, we can create safer and more favorable environments for these majestic creatures.
Furthermore, the study underscores the importance of international cooperation in conserving the marine environment, as migratory species such as humpback whales travel vast distances across the ocean.
Collaborative efforts are essential to ensure that these animals find safe havens, which is crucial to increasing their chances of survival in an ever-changing global environment.
The big picture
What does this mean for the future? These findings shed light on the role of migrating whales as health indicators of Antarctic marine ecosystems.
“Eastern Australian humpback whales have shown a remarkable ability to adapt to changes in their environment, but our study highlights the importance of mitigating human impacts so they can continue to thrive in our rapidly changing oceans,” said Dr Linsky.
“By continuing to monitor and protect humpback whales off the east coast of Australia, we can ensure their health and stability, while providing valuable insights into how other struggling whale populations can be protected.”
The research was published in the journal Research into the marine environment.
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