Humpback whales Megaptera novaeangliae
- How Thomas Edison saved the whales (and reduced the world’s ‘whale footprint’)
- A second chance and a change in awareness
- And now the whales are coming back
- How do you count whales?
- The mystery of whales
- Communication: the animal that sings
- A 500,000 kilometre journey
- How humpbacks eat
He is the most gamesome and light-hearted of all the whales, making more gay foam and white water generally than any other of them.
Herman Melville (1851) Moby Dick
As few as 500
It was only a few decades ago that the idea of seeing a humpback whale off the Queensland coast would have been met with the answer, ‘They’re gone. Dead. Hunted out’. By 1962 a population once estimated at being in the vicinity of 40,000 animals had been reduced to as few as 500.
Humpbacks had become ‘useless’ — ‘commercially extinct’: too few in numbers to make it worthwhile for the last local whaling station at Tangalooma on Moreton Island to pursue and kill them. The brief period of whaling along the east coast of Australia had proven far too efficient, killing too many whales too quickly, resulting in the inevitable population crash (it is believed that up to 95 percent of the east coast population was killed in the decade from 1952 to 1962). Similar exploitation of whales around the world had left many of the larger whale species verging on extinction.
The whale products we didn’t really need
Today, in a time when more people are aware of the products they buy and the impact these products have on the environment, it is hard to imagine buying something that was made from a whale.
And yet, humpback whales were rendered into a range of products. The following is how a humpback whale caught at the Tangalooma whaling station had been used:
- Meat: for pet food, stock feed and added to soups and gravies used for human consumption
- Oil: for glycerine, soaps, margarine
- Gelatine: for photographic films and jellies
- Tendons: for tennis racket strings and surgical stitches
- Glands: for medicines and pharmaceuticals
- Bone: ground up for fertiliser
Even then there were alternatives readily available for all these products. But with fast whaling ships, harpoons with explosive heads, and easy-to-catch whales, nobody questioned whether it was appropriate for whales to be killed for things like dog food and tennis racket strings. The exploitation only stopped when whales became too scarce to be worth hunting — not because the killing was seen as wrong.
How Thomas Edison saved the whales (and reduced the world’s ‘whale footprint’)
Today CFC light bulbs offer us a practical way to save energy and reduce our carbon footprint. When Thomas Edison’s invention, the incandescent light bulb, became the most common form of lighting it helped put an end to the use of oil lamps. In some countries whale oil was widely used in these lamps. The incandescent light bulb helped end the demand for whale oil — and helped save the whales!
A second chance and a change in awareness
Perhaps the only valuable by-product of whaling (but not enough to justify killing whales) was that it allowed scientists to study them closely. Much of our knowledge of whale anatomy and how their giant bodies work was gained by scientists examining dead whales at whaling stations.
From this knowledge grew the realisation that whales were much, much more than a conglomeration of pet food, tennis racket strings and lamp oil.
With a brain weighing more than 5 kilograms, humpback whales were recognised as intelligent animals with well developed sight, hearing and sense of touch. Research into their calls found that male humpback whales had a complex system of repeated patterns within longer calls that lasted for up to 30 minutes. In other words, they sing! (see Communication)
Observations also showed that they shared many traits with humans. They were inquisitive, they supported and protected their young and other whales when they were injured, they played. The more we found out about them, the more we realised they were like us — and the more we questioned the need for whaling.
Left alone, the remnants of the population staged a miraculous recovery, increasing in number by around 10 percent each year. Chance sightings of whales increased but this time it coincided with a change in the way we thought about whales. With whales no longer seen as a resource, people became curious about them and as whale numbers grew, these whales lured a new fleet of boats to sea — not to kill them but to simply watch them. A part of this curiosity comes from wondering what these intelligent animals think (and when we go to watch them, do they watch us?).
And now the whales are coming back
Before whaling an estimated population of around 40,000 humpback whales migrated along the east coast of Australia. By 1962 when whaling ended, there may have only been 500 whales left.
Since then a series of research and monitoring programs has allowed accurate estimates to be made of the growth rate and size of the humpback whale population that migrates along the east coast of Australia.
The whale population on the east coast is now estimated to be increasing by about 10 percent each year. In 2007 the total population estimate was between 9,500 and 12,500. Population estimates are made every three years.
How do you count whales?
By counting the total number of whales in a defined area from the air and then comparing this with the number seen from a land-based vantage point, researchers can determine what proportion of the total number of whales passing through the area can be seen from the land. This has allowed land-based sightings from prominent headlands (e.g. Cape Byron in northern New South Wales, Point Lookout on North Stradbroke Island) to be used as a reliable technique for obtaining good estimates of the number of whales moving along the coastline each year.
Further information supporting the estimated rates of annual increase in the whale population has been gained from counting individual whales at certain locations (e.g. Hervey Bay near Maryborough and Cape Byron) each year. Individual whales can be identified from the unique markings on their flukes.
Acoustic surveys are also being used as a way of estimating the number of males in an area. This information is being used as a tool to verify and refine population estimates.
By combining all these techniques there is now an accurate estimate of just how many whales there are and the rate at which the population is increasing.
The mystery of whales
Worldwide, whale watching as a tourist industry may generate more than $1 billion a year.
There will always be an element of mystery about whales. Spending more than 70 percent of their lives under the water—sometimes at depths of up to 100 metres—it’s only natural that they inspire enormous curiosity and awe when they do appear at the surface for a few seconds.
Knowing the basic statistics about a humpback whale does little to prepare you for the surprise and awe of seeing a 16 metre, 40 tonne mammal all but completely lift itself out of the water then crash back into the sea sending spray 10 metres into the air.
When a whale surfaces, the simple act of exhaling results in a ‘blow’ of spray and air that shoots up to four metres in the air as it empties 90 percent of the contents of its lungs in less than a second. The whale’s lung capacity is about the same volume as a small car.
Then, when it breathes in and dives, it can stay submerged for up to 30 minutes.
|Size||usually up to 16 metres females slightly bigger)|
|Fluke width||Up to 4m|
|Pectoral fin length||Up to 5m (about a third of the total body length)|
|5kg (60cm circumference x 22cm long)|
|Blood volume||10–15% of body weight (up to 6.5 tonnes of blood)|
|Skull||2–5m long x up to 2m wide|
|Food consumption||Up to 2000kg/day when feeding|
|Life expectancy||Up to 50 years|
|Gestation period||11–12 months (whales can breed every year but usually give birth every 2–3 years)|
|Size of calf (at birth)||4–6 metres|
|Breeding age||5–7 years old|
|Migration||9000km (round trip)|
|Speed||normally 3.5 knots (6.5km/hr) – 5 knots (9.2km/hr) (fastest speed 9-10 knots (18.5km/hr)|
|Population size (Area V population)||Approx. 12 000 in 2008 (increasing by around 10% each year)|
When Herman Melville created the fictional white sperm whale ‘Moby Dick’ he drew on our strong fascination for the large and unusual. Ever since people have been intrigued by rumours of giant white whales. When a white whale appeared in the waters off Byron Bay in 1991 it attracted enormous public interest. Since then everyone has been watching for the white whale with a zeal that would do Captain Ahab proud.
Three white whales have been seen in Queensland waters, Migaloo, Bahloo and a white calf sighted in the Whitsundays in 2011. A white calf was also briefly seen off Sydney in 2008.
In Queensland, whales that are totally white or predominantly white are declared ‘special management marine mammals’. This gives these whales extra protection from disturbance by increasing the distance that boats and other watercraft must keep from them.
Migaloo is a white humpback whale that was first seen in 1991 off Byron Bay. At the time it was believed to be 3-5 years old. It has been seen migrating along the east coast in most years since then in locations ranging from Tasmania, Victoria and New South Wales, and as far north as Cape Tribulation in north Queensland (2007).
In 1998 and 2003 it was recorded singing, indicating that Migaloo is a male. This was confirmed in 2004 when tissue samples from Migaloo were analysed.
In August 2003 when he was 15-17 years of age, he was hit by a sail-boat off Townsville and now bears a scar arcing diagonally across the left side of his back halfway between his blowhole and dorsal fin.
In July 2008 another white whale was seen in Queensland waters. This one, named Bahloo after an Aboriginal moon spirit, was first seen swimming off the Gold Coast. Little is known about Bahloo other than that it has a few black spots on its head and tail.
Communication: the animal that sings
We are aware of no other animal besides man in which this strange and complicated behaviour occurs, and we have no idea of the reason behind it. (Roger Payne  whale researcher who discovered that the calls of humpback whales were structured into songs)
Humpback whales make a range of sounds including wheezes, groans and whistles, but they are best known for the long and elaborate songs that the males sing every year on their northerly migration to Queensland’s coastal waters.
These songs can last for up to 30 minutes and follow a set pattern. An analysis of humpback songs in the waters off Hawaii and Bermuda showed that each song was composed of six passages that contained several phrases. These phrases were made up of two to five sounds and either remained identical throughout the song or slowly changed from beginning to end. These longer passages always occurred in the same order (even if one or two passages were left out the others remained in the same sequence).
Humpback whales either learn these rules of song composition or they are an instinctive behaviour.
Even though male humpback whales have been shown to remember their songs from the previous breeding season, they change them each year. A new song is based on the previous song with some new phrases (these are generally sung faster than old phrases) or modified ones that are made up of the beginning and end of two consecutive phrases from the previous year’s song.
All males from the same area learn the same song and will sing it as they swim to their breeding grounds each year. While they may all sing the same song, they each sing it independently so that the water can be filled with ‘rounds’ of whale song announcing the onset of the breeding season. To hear some recordings of whale song got to http://www.oceanmammalinst.org/songs.html
A 500,000 kilometre journey
Sometime between July and August and somewhere in the protected waters of the Great Barrier Reef a baby humpback whale is born (it’s a boy!). It has been carried by its mother for the last 11 or 12 months. After a one hour labour the young whale emerges tail first with its long pectoral fins folded forward — Five metres long and weighing between one and two tonnes. The mother supports the new calf and lifts it to the surface for its first breath. At birth, the young whale consumes 40 kilograms of milk a day and gains up to one kilogram in weight every hour. In the first week, it starts to develop the pattern of markings that will allow it to be distinguished from other whales.
By the end of August, mother and calf turn south and begin the 4500 kilometre migration to the Antarctic. Along the way the calf will stay close to its mother, suckling up to 40 times a day. The calf also receives its first lessons in navigating the route that it will retrace the following March.
On the way south the mother and her calf are likely to enter Hervey Bay for a few days. The sheltered waters of the Bay are visited by many of the whales on their southern migration between August and October. Here they remain for anything up to a week before continuing south. The adults arrive here first in August, with some still actively courting and mating. They are followed by the juveniles, and then the mothers and calves arrive between mid-September and October, sometimes escorted by another whale. By this time the calf is between four and six weeks old and taking around 500 litres of milk a day. When not feeding he is learning: copying his mother’s behaviour, breaching, and fin and tail slapping.
By November, the humpback whales have reached the Southern Ocean. First to arrive are the pregnant females, followed by the immature whales, and the mature males and ‘resting females’ (i.e. mature females that aren’t pregnant or suckling). The final group to return are the mothers and calves.
Here the whales spend the spring and summer feeding on the immense populations of krill that build up in response to blooms of phytoplankton. An adult whale can eat an estimated 2000 kilograms of krill a day (there may be up to 35 kilograms of krill in a cubic metre of water).
The calf is now five to six months old and is starting to socialise with other whales and feed on krill. It will still stay near its mother and will continue to suckle from her for a few more months.
How humpbacks eat
Whales are divided into two categories based on how they eat (i.e. the toothed whales and the baleen whales). The humpback whale is a baleen whale.
Instead of teeth, a baleen whale has two ‘combs’ made up of about 330 long, stiff bristle-edged strands of keratin (keratin is the fibrous protein that horn, fingernails and hair are made from) hanging from each upper side of its mouth. A single strand of baleen is triangular in cross-section and can be up to 63cm long and 4cm wide. Combined, these baleen strands mesh together to form a sieve.
When feeding, the whale swims into a dense patch of krill or a school of small fish with its mouth wide open and then closes it, pushing the water out through the baleen with its tongue and trapping the food, which is then swallowed. A baleen whale has a number of folds of skin beneath its mouth known as throat pleats (humpback whales have 24). These folds expand to greatly enlarge the area of the whale’s mouth when it is catching prey, allowing it to take in huge amounts of food at a time.
By the end of February the whales have laid down the blubber they will live off for the next nine months—if they take part in the northerly migration (some whales don’t migrate each year). Of the whales that do migrate, all of the mothers and their six to seven metre long calves leave first. A couple of weeks later the juveniles leave with the mature males. Resting females and males follow them after another two or three weeks. The pregnant females stay and feed for another two weeks before leaving in April.
The whales move north in loose groups, covering about 850 nautical miles a month. The mature males start singing to attract a mate. The immature whales along with last year’s mothers and calves reach the tropical waters first around June or July. By now the calf is 8 metres long and has completed its first round trip to where it was born the previous year. At almost a year old, he is fully weaned. He will soon leave his mother, spending more time with other immature young until he becomes a mature adult. Whales become mature at between four and six years of age.
The mature males and females without young then arrive and courting and mating takes place between July and September.
The pregnant females are the last to arrive and give birth sometime between July and August. Occasionally humpback whales give birth anywhere along their migratory route, with an orphaned calf being found near Sydney in August 2008. As the whale population increases, so will the number of orphaned calves that are found.
The calf born the year before may now live for 50 years—that means it would swim up to 500,000 kilometres during its lifetime.
If you see a stranded whale, alive or dead, please call the RSPCA Qld on 1300 ANIMAL at any time.