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07-06-2024

Humpback whales felt less stressed during the pandemic

Life under the sea is filled with simple pleasures, free from the hustle and bustle of human life. Amidst the stress of the COVID-19 pandemic, who would’ve thought that there would be an upside to the lockdowns for humpback whales?

A team from the University of Queensland, led by the inquisitive Dr. Jake Linsky, stumbled upon a fascinating discovery: the calming effect on migrating humpback whales off Australia’s east coast.

Dr. Linsky, part of UQ’s School of Environment, has been studying the health of this species out of Moreton Bay Research Station. When not cooped up in a lab, he’s out taking drone photographs and collecting blubber samples to gauge the health of these freewheeling cetaceans.

“Checking up” on whales

With their remarkable recovery from historical whaling, the health of these Australian humpback whales has been a topic of great interest. The team has been keen on using cutting-edge tools to check on their well-being.

“We used drone photographs 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 made one of the most successful recoveries from historical whaling, so we wanted to use the latest tools at our disposal to provide a check-up on their health.”

Decoding humpback whales stress levels

“We also used small boats to approach whales and collect small samples of skin and blubber from the whales’ flanks,” Dr. Linsky added.

Once collected, these blubber samples were examined for hormones and gene expressions related to stress, energy reserves, and immune health. A striking revelation was the significantly lower cortisol concentrations- a stress hormone – in 2021 when compared to 2020.

Reduction in environmental stressors

This decrease in cortisol levels indicates a reduction in environmental stressors over the year. How did this happen?

Dr. Linsky attributes the change to several factors, including a shift in climate and the drastic alteration of human activity during the pandemic.

“Several things happened during this period that likely contributed to our findings, including a shift in climate into La Niña and dramatic changes to human activity during the pandemic.”

“Our gene expression results also raise a further hypothesis that the whales may have been responding to a decline in pollutants in their remote feeding waters.”

“Previous studies have found similar changes to stress hormones in whales on the opposite side of the Antarctic continent – our findings support the idea that these changes occurred throughout the Southern Ocean.”

Implications for conservation policies

The findings from Dr. Linsky’s study 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 argument for establishing marine protected areas and enforcing stricter regulations on maritime traffic and pollution.

By minimizing human-induced stressors, we can create safer and more conducive environments for these majestic creatures.

Additionally, the study underscores the importance of international collaboration in marine conservation, as migratory species like humpback whales traverse vast oceanic distances.

Joint efforts are essential to ensure these animals encounter safe havens. This is crucial to enhance 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 demonstrated a remarkable ability to adapt to changes in their environment, but our study emphasizes 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 also offering valuable insights into how other struggling whale populations might be conserved.”

The study is published in the journal Marine Environmental Research.

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