Life under the sea is full of simple pleasures, free from the hustle and bustle of human life. Amidst the stress of the COVID-19 pandemic, who would have thought that there would be any benefit to the lockdown for humpback whales?
A team from the University of Queensland, led by the inquisitive Dr. Jake Lynskey, stumbled upon an astonishing discovery: the calming effect on migrating humpback whales off the east coast of Australia.
Dr Lynskey, part of UQ’s School of Environment, studies the health of this species from Moreton Bay Research Station. When he’s not cooped up in a lab, he’s out taking drone photos and collecting blubber samples to assess the health of these free-ranging cetaceans.
“Checking” the whales
With their remarkable recovery from historic whaling, the health of these Australian humpback whales is a topic of great interest. The team strives to use cutting-edge tools to check their well-being.
“We used drone imagery and blubber samples to assess the health of East Australian humpback whales in the waters off Minjerribah – North Stradbroke Island – during their migration in 2020 and 2021,” Dr Linsky said.
“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 provide a check on their health.”
Decoding stress levels in humpback whales
“We also used small boats to get close to the whales and take small samples of skin and blubber from the whales’ flanks,” Dr Linsky added.
Once collected, these fat samples were examined for hormones and gene expression related to stress, energy reserves and immune health. A striking finding was significantly lower concentrations of the stress hormone cortisol in 2021 compared to 2020.
Reducing environmental stressors
This decrease in cortisol levels indicates a decrease in environmental stressors over the course of the year. How did this happen?
Dr Linsky attributes the change to several factors, including climate change and the drastic change in human activity during the pandemic.
“Several things happened during this period that likely contributed to our findings, including La Niña climate change and dramatic changes in human activity during the pandemic.”
“Our gene expression results also raise the additional hypothesis that the whales may have responded to a reduction in pollutants in their remote 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 conservation policies
The findings of Dr. Linsky’s research have critical implications for conservation policies aimed at protecting humpback whales and other marine species.
The observed decrease in cortisol levels during periods of reduced human activity supports the case for establishing marine protected areas and enforcing stricter regulations on marine traffic and pollution.
By minimizing human-induced stressors, we can create safer and more conducive environments for these majestic creatures.
The study also highlights the importance of international cooperation in marine conservation, as migratory species such as humpback whales travel vast ocean distances.
A concerted effort is essential to ensure that these animals find safe havens. This is crucial 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 migrating whales as indicators of the health of Antarctic marine ecosystems.
“Eastern Australian humpback whales have demonstrated a remarkable ability to adapt to environmental change, but our study highlights the importance of mitigating human impact so that they can continue to thrive in our rapidly changing oceans,” Dr Linsky said .
“By continuing to monitor and protect humpback whales off Australia’s east coast, we can ensure their health and stability, while offering valuable information on how other struggling whale populations can be conserved.”
The study was published in the journal Study of the marine environment.
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