After being hunted to near extinction in the last century, humpback whales are making a stunning comeback. Carla Hüsselmann explores how these marvelous giants are reclaiming their migration routes and how they counter climate change.
These usually gentle giants are renowned for their mysterious, complex songs of low-pitched chirps, groans and howls, which were used to spearhead the ‘Save the Whale’ campaign in the 1960s and heralded the dawn of the modern conservation movement. Famed for the improbable way in which they effortlessly breach the ocean’s surface, hoisting their 40-odd ton bulk high above the waves in aerial acrobatic feats, they were immortalised as “the most gamesome and lighthearted of all whales” in Herman Melville’s Moby Dick.
But there’s nothing playful about a combative pod of male humpback whales engaged in a mating ritual known as the most epic courtship battle in the animal kingdom. Just ask those handful of cinematographers who’ve filmed from the fringes of the most impressive display of power in the ocean, where enraged males race against each other and collide their 12m-long bodies into each other at top speed to earn the privilege of a female’s attention. While the female sets the pace, all explodes in mayhem around her, as the battle-scarred males boom their intent and blow furious bubbles under the water and bursts of their characteristic plumes from their blowholes, head-butting and ramming one another, while slashing with their massive flukes. Escalating their conflict, some appear to hover above the sea as they surge skywards, revealing their long, wing-like pectoral fins and slapping them against the water, crashing backwards into the waves and sometimes their rivals. This brutal rivalry can last for hours and stretch over 30km and longer.
As intriguing is how they battle their sworn enemies, killer whales – and even defend other species against the wolves of the sea. From grey whales to sea lions, seals, sunfish, porpoises and other marine creatures, whale researchers have recorded how humpback whales risk injury rescuing entirely different species from these efficient killers. Last year a leading marine biologist, Nan Hauser, even reported that a humpback whale saved her from the toothy clutches of a tiger shark off the Cook Islands in the South Pacific. Whether out of instinct, personal benefit, a troubled history with their arch-nemeses or some form of altruism, these intelligent whales show regard for other species – a regard our species didn’t bother reciprocating when these protectors faced a battle they couldn’t win.
The commercial whaling industry drove humpbacks – and other whales including the sperm, fin, sei and blue – to near extinction last century. Approximately 220,000 Southern Hemisphere humpback whales were slaughtered from the 1900s to the 1970s – and it’s estimated that only about 500 remained in southern African waters, says Chris Wilkinson, marine biologist and technical manager for the University of Pretoria’s Mammal Research Institute’s Whale Unit. This is an absolute tragedy, considering how integral they are to our oceans’ health. ‘Whales not only drive essential ecosystems and maintain the ecological balance of our oceans, but have an important influence on the climate because they’re crucial to ocean carbon absorption,’ Wilkinson explains.
For years, he’s been tirelessly tracking the health of southern right whales in Hermanus and started investigating how humpback whales were recovering from whaling, as part of his Masters degree in Conservation Science through the Cape Peninsula University of Technology (CPUT) under the supervision of leading marine biologist Professor Ken Findlay. Earlier this year one of his surveys garnered attention worldwide when he reported a remarkable rebound in the humpback whale population. He and his team estimated that more than 30,000 may be migrating across the Western Indian Ocean, based on extrapolations of previous years’ data.
For two months in 2018 and this year, they counted the giants from observation towers as they migrated past Cape Vidal in northern KwaZulua-Natal from summer feeding grounds in Antarctica to winter breeding grounds in Mozambique. ‘From the work done by the Whale Unit’s previous director Professor Ken Findlay, we knew that the humpback whales were recovering at about 9% per annum, so I knew there were going to be a lot of whales, but I wasn’t quite prepared to record the large number we spotted! I had to quickly get more data sheets printed to record them all, which wasn’t easy considering that the nearest A3 printer was in Richards Bay 150km away. This year we were far more prepared and broke last year’s record, with each tower tracking over 100 groups of whales in one day. That is tracking 10 groups an hour, taking four observations and angles with the theodolite per group! From 7am to 5pm, the guys in the towers were constantly shouting out angles and writing.”
It’s important to realise that the whales passing Cape Vidal are a fraction of the entire east coast population and that the projected estimate of 30,000 is taken from the Cape Vidal sightings and extrapolating it by the four migration paths this population takes, he explains. ‘Further analyses are currently happening on the raw data that will eventually provide final numbers,’ says Wilkinson.
Ocean optimism?
It’s a victory worth celebrating: the rebound of the humpback whale population is undoubtedly an ocean conservation success story. However, it’s only one species of whale, conservationists caution. The majestic creatures now face another battle for survival: six out of the 13 great whale species are classified as endangered, even after decades of protection, reports the WWF.
‘Many of SA’s whale populations are showing signs of recovery from severe whaling pressure over the last 250 years, mainly due to the removal of the impact of whaling,’ says Professor Ken Findlay, CPUT’s Research Chair in Oceans Economy. ‘If the animal’s environment isn’t degraded, then the removal of the impact should result in a recovery. That said, there are recent changes in some whale population growth rates, which suggest environmental changes, so that changes in recovering whale population growth rates may be a valuable indicator of ocean change.’
Humans have created more gargantuan modern threats to whales, including pollution, climate change, poor ocean governance, increased shipping activity and ship collisions, fishing gear entanglement, and oil and gas development that disrupt whales’ feeding and breeding grounds, migratory patterns and even damage their hearing.
Overfishing has also lead to a decline in the fish stocks they need to survive and climate change’s warming water temperatures and acidification of the sea will have a direct impact on their habitats and abundance of food sources. As the polar ice increasingly melts, ship traffic may increase too as more routes are opened up, leading to more pollution, garbage and noise. ‘The shift in food availability due to climate fluctuations has already hurt the reproductive rates of the endangered North Atlantic right whale,’ reports the WWF on their site. In fact, as few as 300 North Atlantic right whales remain.
‘South Africa has two populations of humpbacks, the C (east coast) and B (west coast) populations, so these are proudly southern African whales, and every effort must be made to protect them on their migration past south Africa,’ says Wilkinson. ‘More marine protected areas (MPA’s) need to be proclaimed, shipping lanes and ships’ speeds need to be monitored while whales migrate, and there should be no seismic surveys during whale migration season. For us to do anything to disrupt or threaten this amazing recovery would be absolutely catastrophic and undo all the good work we’ve done as a global population.’
Don’t allow history to repeat itself.
*Get involved in conserving our whales at http://adoptawhale.co.za/
The gruesome history of commercial whaling
Between 1900 and 1999, 2.9 million whales were killed by the whaling industry: 276,442 in the North Atlantic, 563,696 in the North Pacific and 2,053,956 in the Southern Hemisphere, according to a 2015 study published in the Marine Fisheries Review journal.
From the 18th century the world was powered by whale oil for use in streetlights, heating and cooking stoves. It was used in household products like soap, margarine and cooking oil and sperm whale oil was used as a lubricant for delicate machinery, its wax for candles and in cosmetics and pharmaceuticals. In both world wars, whale oil was extremely important in the manufacture of nitroglycerin for explosives.
Modern whaling in South African began in Durban in 1908 after reports of the abundance of whales in southern African waters were received in Norway. Norwegian entrepreneurs descended on our shores and by 1909, floating factories were operating off the west coast at Saldanha Bay. ‘The success of the entrepreneurial whaling companies in South Africa in 1909 and 1910 resulted in a whaling boom in the region and large whaling stations were established on the west coast at Donkergat near Langebaan and on the Bluff in Durban,’ relates Wilkinson.
Elderly Durban residents can still recall the suffocating stench of decaying whale carcasses that wafted across the Bluff. By 1912, the burgeoning city had six whale processing plants.
Thousands of whales were slaughtered every year in the most grotesque manner. The whaling ships would sail up close to whales and shoot them with heavy metal harpoons loaded with explosive charges, which would explode inside them. The whalers would then pump the dead whale full of compressed air so it would float and then the ship would tow the whales back to shore. From 1954 whales were spotted by plane and whalers would descend on the unsuspecting creatures.
During the 1960s Durban was home to the largest whaling station in the world, the Union Whaling Company. Thankfully the whale conservation movement started gaining momentum all around the world and there was growing pressure to abandon whaling. By the mid 1970s, the Union Whaling Company was shut down, primarily because it was becoming harder and harder to find whales to slaughter. South African whaling was finally terminated in 1975.
Why whale poo matters
Whales are crucial to ocean carbon absorption and if whale numbers dwindle, it could lead to increased greenhouse gases in the atmosphere, scientists say. Believe it or not, they facilitate carbon absorption through their faecal plumes, aka their poo!
‘Whales generally don’t poo deep down in the ocean but perform that function at the surface, which triggers an astounding trophic cascade (ecological processes that tumble from the top of an ecosystem to the bottom),’ explains Wilkinson. ‘Their faecal matter is rich in nutrients, which fertilise the plant plankton on which animal plankton feed. In turn, those tiny creatures are food to whales and other sea animals, like the fish you might be having for dinner tonight. But the benefits don’t end on your dinner plate. Plant plankton absorbs significant amounts of carbon from the atmosphere. When the plant dies, it takes that carbon dioxide down to the ocean floor. Basically, the more whales, the more poo, the more plant plankton, the more krill, fish and other sea creatures, the more food security for both people and animals, the less carbon in the atmosphere, and the healthier the climate!’
With climate change, warming waters will harm whales, in turn reducing the ocean’s ability to suck in carbon and leading to even more temperature increases. It’s worth remembering that nothing in the natural world – or what we as humans do – occurs in isolation.
View article published in October 2019 @ Khulumaonline.co.za
Photo credit: Berno Phillipson of Valhalla Photography
Carla Hüsselmann 