17 Aug 2020
AUSTRALIAN HUMPBACK HIGHWAYS
By Chris Johnson, Global Lead, WWF Protecting Whales & Dolphins.
Australia's nature laws are currently undergoing a once-in-10 year review. Help us advocate for stronger nature laws to protect our precious wildlife and the places they call home - before it's too late.
Humpback whales are one of the oceans’ most inspiring species. Their scientific name, Megaptera novaeangliae, means ‘big-winged New Englander’ and this truly captures their spirit. Their curious nature is a reflection of the awesome nature of the sea. I’ve been lucky to study them first-hand in the Antarctic, floating on a tiny zodiac (an inflatable rubber boat) surrounded by icebergs on a frozen sea. The size of a bus, these huge marine mammals are inspirational when they roll over, staring eye-to-eye looking back at you. As they swim effortlessly through the water, they are expressive, dynamic and epic navigators of our seas.
A conservation success story
More than ever, there are important reasons to step back and celebrate how far humpback whales have made their way from the brink of extinction to become a global conservation success story. In conservation, it’s important to reflect on the challenges we overcome and celebrate the victories we achieve. But, it’s key to keep our eyes on emerging threats that may undo that collective effort, so we protect them for years to come.
During the 20th century, unchecked commercial whaling dramatically reduced whale populations throughout the Southern Ocean, driving many species to the brink of extinction. More than 725,000 fin, 400,000 sperm, 360,000 blue, 200,000 sei and 200,000 humpback whales were killed during this time. It’s estimated that when the Australian east coast whaling industry ended in 1963 (with whaling officially ceasing in Australia in 1978), the east coast population of humpbacks had been reduced to a little over 100 individuals. Through national and global conservation efforts their population is bouncing back, growing at a rate of about 10% a year. A big contributor is the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) which protects all cetaceans (whales, dolphins and porpoises) in Australian waters.
But while the EPBC Act played an integral part in the protection of the majestic whale species, our current nature laws aren’t doing enough to protect our native species on land.
Important for the health of our oceans and to help combat climate change
People often ask me, why we should care about whales such as humpbacks, southern rights and blues, among others. There’s increasing evidence that protecting our iconic whales is critical in maintaining ocean health. They contribute to regulating global climate and capturing carbon from the atmosphere during their lifetime, which has tremendous benefits for our health.
Let me explain. Over a lifespan of around 60 to 80 years, whales – especially great whales – accumulate an average of 33 tonnes of CO2. By comparison, a tree absorbs up to 48 pounds of CO2 a year. When they die, whales sink to the bottom of the ocean, locking that carbon away for hundreds of years. Part of the carbon capture potential for whales is due to their role in increasing phytoplankton productivity, a phenomenon called “the whale pump”. As they rise up through the ocean to breathe and migrate across the globe, whales leave a trail of iron- and nitrogen-rich waste behind them, providing ideal growing conditions for these microscopic creatures. And while they may be small, phytoplankton play an enormous role in regulating our atmospheric conditions, contributing at least 50% of all oxygen and capturing an estimated 37 billion metric tonnes (40%) of all CO2 produced.
The International Monetary Fund calls whales “nature’s solution to climate change”. Bringing back populations of great whales is an important strategy with many benefits. In economic terms, whales contribute to maintaining the food web of the commercial fishing industry, which is valued at over US$150 billion. Globally, whale and dolphin watching is valued at over US$2 billion annually for the global tourism industry.
Epic yearly migrations
Right now, our humpback whales are finishing their migration north, travelling along humpback highways from their Southern Ocean feeding grounds along the icy edges of Antarctica. Over the next few months, they’ll spend time in their winter grounds in northeast and northwest Australia to mate and give birth. From September-November, they turn around and head back down south to the Antarctic to feed on krill in the summer months, stocking up on energy for the year.
In fact, there are multiple humpback highways, or migration corridors, around the world where they make epic round trip journeys, thousands of kilometres a year! One population that we study breeds along the coast of the eastern tropical Pacific and migrates to the Antarctic Peninsula over 8,500 kilometres one way!
Imagine swimming in the ocean without a GPS (or Google Maps) to rely on for navigation. How these ocean giants navigate the seas each year from the Antarctic and back is one of nature’s true wonders. It’s something that is easy to take for granted. And it is incredibly fragile with growing risks ahead.
Risks ahead to navigate
Each year, along the Australian coastal humpback highways, unlucky individuals become entangled in nets or fishing gear, their accidental capture is termed ‘bycatch’ or unintended catch. Globally, an estimated 300,000 whales and dolphins are killed each year as a result of fisheries bycatch.
There is increasing ship and boat traffic that overlaps important areas for whales. Growing ocean noise which can obscure the ability of whales to hear natural sounds in the ocean and limit their ability to communicate across distances. As curious humpback calves stay with their mothers for 11–12 months before becoming independent, these journeys are becoming trickier to navigate. Add to this climate change, which is impacting important ocean habitats where whales breed in Australia and feed in the Southern Ocean.
To address the growing threats to whales, WWF has launched a new global conservation programme to Protect Whales and Dolphins that will be coordinated from WWF-Australia. Over the next few years, we will ramp up efforts to reduce threats and protect these important highways for migratory whales such as humpbacks so they can continue to make safe passage on their yearly journey back home to Australia.
Australia's nature laws are undergoing a once-in-10-year review. Will you ask your local politician to protect our wildlife and their remaining homes?