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Climate Change Could Be Killing Humpback Whales

In 1972, off the coast of Alaska, a humpback whale was spotted and named Festus. Festus, weighing up to 40 tonnes and spanning 17 meters in length, became a beloved fixture for whale watchers, locals, and scientists for 44 consecutive summers. His annual migration from the cold, nutrient-rich waters of the North Pacific to Hawaii for winter breeding was well-tracked and observed.

However, in June 2016, Festus was tragically discovered lifeless, floating in Glacier Bay National Park. His demise, attributed primarily to starvation, served as a reminder of the perilous impact of climate change on marine ecosystems. Scientists linked Festus’ fate to the most severe marine heatwave on record, which ravaged the North Pacific from 2014 to 2016.

A recent study published by the Royal Society of Open Science sheds light on the catastrophic consequences of this unprecedented event. Led by Ted Cheeseman, a biologist at Southern Cross University, the research revealed a staggering 20% decline in the humpback whale population of the North Pacific between 2013 and 2021. The marine heatwave significantly diminished ocean productivity, disrupting the delicate balance of the ecosystem and depriving humpbacks of vital sustenance.

Humpback whales, once on the brink of extinction due to centuries of relentless hunting, experienced a remarkable resurgence following the 1982 ban on commercial whaling by the International Whaling Commission. By 2012, their population in the North Pacific peaked at nearly 33,500 individuals, marking a monumental triumph in Conservation efforts. The subsequent removal of humpbacks from the US Endangered Species Act in 2016 was a testament to this remarkable recovery.

However, this resurgence proved fleeting in the face of escalating climate pressures. The marine heatwave of 2014-2016, characterized by sea temperatures soaring 3-6°C above average, triggered a cascade of ecological disruptions. Declining phytoplankton levels led to a scarcity of food throughout the marine food web, leaving humpbacks and other marine species vulnerable to starvation and reproductive failure.

Festus’s demise epitomized the dire consequences of prolonged heatwaves on marine life. The phenomenon not only starved whales but also led to the emergence of “skinny whales,” rendering them susceptible to diseases and reproductive challenges. Ari Friedlaender, an ecologist at the University of California Santa Cruz, said that the heatwave likely “impacted the pregnancy rates in the population” and “led to the demise of a certain number of animals.”

The plight of humpbacks extended beyond Festus’s tragic end, as evidenced by alarming trends in the Au’au channel between Maui and Lanai. Mother-calf encounter rates plummeted by nearly 77% between 2013 and 2018, signaling a rapid decline in reproductive success.

In the face of adversity, collaborative efforts spearheaded by scientists like Ted Cheeseman and initiatives like Happywhale have emerged as beacons of hope. Happywhale, dubbed the “Facebook for whales,” harnesses citizen science to compile a vast database of humpback tail fluke images, facilitating crucial research on population dynamics and ecological health. Additionally, Martin van Aswegen, a PhD candidate at the University of Hawaii, has leveraged drones to monitor humpback whales, providing invaluable insights into their behavior and physiology. Long-term monitoring efforts, coupled with international collaboration, offer a glimmer of optimism amidst the ecological turmoil.

As we confront the sobering reality of Climate change, Festus’s legacy is a reminder of the urgent need for concerted action. The fate of humpback whales serves as a barometer of the ocean’s health. The alarming rate at which these amazing animals are dying is a signal for change.