The humpback whale is a species of baleen whale. It is one of the larger rorqual (*) species, with adults ranging in length from 12 to 16 m and weighing around 25 to 30 metric tons. The humpback has a distinctive body shape, with long pectoral fins and a knobbly head. It is known for breaching and other distinctive surface behaviors making it popular with whale watchers. Males produce a complex song lasting 10 to 20 minutes, which they repeat for hours at a time. All the males in a group will produce the same song, which is different each season. Its purpose is not clear, though it may help induce ‘heat’ in females. Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 km (16,000 miles) each year. They feed in polar waters, and migrate to tropical or subtropical waters to breed and give birth, fasting and living off their fat reserves. Their diet consists mostly of krill and small fish. Humpbacks have a diverse repertoire of feeding methods, including the bubble net technique. (see video at the end of the blog)
Like other large whales, the humpback has long been a target for the whaling industry. The species was once hunted to the brink of extinction; its population fell by an estimated 90% before a 1966 moratorium. While stocks have partially recovered to some 80,000 animals worldwide, entanglement in fishing gear, collisions with ships and noise pollution continue to affect the species. Credit: https://en.wikipedia.org/wiki/Humpback_whale
(*) Rorqual whales (Family Balaenopteridae) are baleen whales that have 25-100 parallel, pleated throat grooves (ventral grooves) that extend from the throat to the flippers.
Humpback Whales have a worldwide distribution involving two broad population groups that do not appear to mix - one in the Northern Hemisphere and one in the Southern Hemisphere.
Humpback whales were decimated by commercial whaling in the 19th and early 20th century. They were one of the first species protected under the Endangered Species Conservation Act, the predecessor to the Endangered Species Act (ESA) in 1970. When the ESA was passed in 1973, the humpback whale was listed as endangered wherever found. Humpback whales are also protected under the Marine Mammal Protection Act.
Thanks to global conservation efforts including the Endangered Species Act, the current population has rebounded to nearly 80,000 Humpback whales up from a low-point of 10,000 to 15,000 worldwide.
Fortunately, once hunted almost to extinction, the population of humpback whales that swims the seas between South America and Antarctica has bounced back. Humpback Whales are also found in the waters off coastal Australia and have recovered from near extinction.
As for Australia, the Australian Humpback Whale population were hunted and killed for commercial gain until the early 60’s. This saw their decline in population to just 300 whales. They were in serious danger of extinction. A ban on whaling was issued by 1965 and since then the population has seen a remarkable comeback with last official counts in 2016 identifying a population of around 20,000 humpback whales.
As humpback whale populations have rebounded to up to 90% of pre-whaling numbers in Australian waters, they should no longer be officially considered a threatened species, new research has found. The review of scientific research (https://www.sciencedirect.com/science/article/) found humpback numbers off the west coast of Australia had increased at a rate of about 9% a year since 2012, and by about 10% a year on the east coast. The increase is among the highest documented in the world, the paper said, and shows no indication of diminishing.
“Continued monitoring is needed to understand how these whales will respond to modern threats and to climate-driven changes to their habitats,” researchers wrote in a paper published in the Royal Society Open Science Publishing “The population status is much more optimistic than previously thought and abundance should reach its pre-exploitation level within the next 10 years or so, assuming mortality from anthropogenic threats remains low.”
Commercial whaling of humpback whales is prohibited by the International Whaling Commission (https://iwc.int/home). It is illegal to approach a humpback whale within 100 metres by sea, or 300 metres by plane. Nevertheless and sadly, some humpbacks are still hunted, for livelihood purposes, in Greenland. Native people are allowed to kill a limited number of whales because whaling is a major part of their culture, according to Whale Facts. Norway, Iceland and Russia kill large numbers of whales each year. Japan also continues to hunt humpbacks for scientific reasons.
But at least - for once - it’s mostly good environmental news, that the humpback whale population has come back from the brink of extinction worldwide! Enjoy the following “Whale Song”...♪♪♪
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🎥 (2:57) Whale Song - Oceania Project
🎥 (1:44) Whales Team Up in Amazing Bubble-Net Hunt - National Geographic
In the summer, southeastern Alaska's waters teem with humpback whales that have migrated north to feed on herring and other fish. One of their most fascinating behaviors is bubble-net feeding, a complex and coordinated tactic for capturing many fish at once. Andy Szabo, director of the Alaska Whale Foundation, and naturalist Steve Maclean explain the phenomenon while aboard the National Geographic fleet on a recent voyage to Alaska's Inside Passage.
REFERENCES
ABC Radio Brisbane, 2015 (viewed 10.06.2020)
Independent, Oct 2019 (viewed 11.06.2020)
Our World - United Nations University, 2015 (viewed 11.06.2020)
Science News, Nov 2019 (viewed 11.06.2020)