Life under the sea is full of simple joys, free from the hustle and bustle of human life. Amidst the stress of the COVID-19 pandemic, who would have thought that locking up humpback whales would have a positive impact?
A team from the University of Queensland, led by the inquisitive Dr. Jake Linsky, made a fascinating discovery: a calming effect on migrating humpback whales off the east coast of Australia.
Dr. Linsky, part of UQ’s School of Environment, studied the health of the species from Moreton Bay Research Station. When he’s not cooped up in the lab, he takes drone photos and collects blubber samples to assess the health of these free-roaming cetaceans.
“Control” in whales
With their remarkable recovery from historic whaling, the health of these Australian humpback whales is a topic of great concern. The team was excited to use state-of-the-art tools to monitor their well-being.
“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,” said Dr. Linsky.
“This population has made one of the most successful recoveries from historic whaling, so we wanted to use the latest tools at our disposal to ensure their health is in check.”
Decoding the stress level of humpback whales
“We also used small boats to get close to the whales and collect small samples of skin and blubber from the whales’ flanks,” added Dr. Linsky.
Once these samples were collected, they were examined for hormones and gene expression related to stress, energy reserves and immune health. A notable finding was significantly lower concentrations of cortisol – the stress hormone – in 2021 compared to 2020.
Reducing environmental stressors
This decrease in cortisol levels indicates a reduction in environmental stressors over the course of the year. How did it happen?
Dr. Linsky attributes the change to several factors, including climate change and a drastic change in human activity during the pandemic.
“Several things happened during this period that likely contributed to our findings, including a shift in climate to La Niña and dramatic changes in human activity during the pandemic.”
“Our gene expression results also raise the additional hypothesis that whales may have responded to a decrease in pollutants in their distant feeding waters.”
“Previous studies have found similar changes in stress hormones in whales on the opposite side of the Antarctic continent – our findings support the idea that these changes have occurred throughout the Southern Ocean.”
Implications for nature conservation policy
Conclusions of the study Dr. Linský have major implications for conservation policies aimed at protecting humpback whales and other marine species.
The observed decline in cortisol levels during periods of reduced human activity supports the argument for establishing marine protected areas and enforcing stricter regulations on marine traffic and pollution.
By minimizing human-induced stressors, we can create a safer and more conducive environment for these majestic creatures.
Additionally, the study highlights the importance of international cooperation in marine conservation as migratory species such as humpback whales cross vast oceanic distances.
A concerted effort is necessary to ensure that these animals meet safe havens. This is essential to increase 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 migratory 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 Australia’s east coast, we can ensure their health and stability while offering valuable insights into how other populations of struggling whales might be conserved.”
The study is published in a journal Marine environment research.
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