September 20, 2010

A whale of a time

Moreton Island lies about 40 kilometres from the port of Brisbane, in Moreton Bay. It is the third-largest sand island in the world (after Fraser and North Stradbroke islands, which are also off the Queensland coast): it's 38km from north to south and 8km across at its widest point. (I'm told the sand originated in the Blue Mountains west of Sydney.) In the northeast corner is the only rocky bit, on which perches Cape Moreton lighthouse, Queensland's oldest.
It was just off this point last week that I saw the first whales I've ever seen, apart from on a David Attenborough programme. They were Southern Ocean Humpbacks, the fifth-largest animals on earth. Humpbacks measure between 14 and 18 metres in length and weigh up to 50 tonnes: a newborn can be 4 or 5 metres long and weigh 2 tonnes. They migrate at least 6,000km during the southern hemisphere winter.

In the summer Humpbacks gorge themselves silly on krill and small fish in the cool antarctic waters, building up fat stores that they live off while they migrate and breed. An average-sized Humpback will eat between 2,000 and 2,500kg of food a day. They are baleen whales, which means that instead of teeth they have a comb-like structure that enables them to sieve out large amounts of small fish from huge mouthfuls of seawater. From June onwards, Humpbacks travel to warmer semi-tropical waters off northern Queensland where they mate and where pregnant females give birth. They rarely feed while they're up north.

In August they start heading south again, mother and calf pods often sheltering in bays such as Hervey Bay and near the Moreton Bay islands. The calves grow rapidly: they drink at least 250 litres of milk a day, and it's very fatty milk so they gain 45kg a day during their first weeks of life. They are weened at about 11 months, by which time they measure up to 9 metres in length.

Humpbacks are thought to use landmarks to help them navigate, which is why they travel relatively close to the coast. They are inquisitive creatures, often coming to within a few metres of a boat to investigate. Both these facts are great from the point of view of whale-watchers... and whale-hunters. As you sit comfortably on a whale-watching cruise boat, it's easy to forget how recently Tangalooma on Moreton Island was Queensland's only whaling station, for 10 years from 1952. (There was another one at Byron Bay in northern New South Wales.)
During those 10 years Humpback numbers off eastern Australia were decimated - from at least 30,000, possibly more, to a few hundred. People have hunted whales for hundreds of years but the invention of the explosive harpoon in the mid-1800s turned it into a much bigger business. In the 20th century, the global Humpback population was reduced by 90 per cent before the International Whaling Commission stepped in and banned the commercial whaling of Humpbacks in 1966. All whaling is forbidden within 320km (200 miles) of the coast of Australia and its citizens are prohibited from taking part in whaling anywhere in the world. Today Tangalooma is a resort with beautiful, unbloodied beaches.
Moreton Island is 98 per cent National Park. From my trusty Gregory's guidebook to Brisbane, I gather there are many beautiful natural wonders such as freshwater lakes and lagoons; sandhills and a sandblow (a sandy area denuded of vegetation by the wind) with shifting dunes; woodland and heath; multicoloured sand cliffs and strange sand formations; vast stretches of beautiful beach; wildflowers and a variety of birds.

There are no sealed roads on Moreton so I fear I will miss out on most of these delights. I am not one for organised tours from resorts; and neither am I likely to own a 4WD. Although I acknowledge the need for the latter in this part of the world, where I come from in the crowded southeast of England, where almost all places are accessible by paved road, those using large gas-guzzlers on the school run are the subject of derision, if not loathing. And I find it a tad irritating having to watch out for what we know as 'Chelsea tractors' on a beautiful, otherwise deserted beach. North Stradbroke Island next time, on my bike maybe.

Meanwhile, back on Moreton, as I watched the Humpbacks, I found myself wanting to know as much as possible about their behaviour. They get their name from the way they arch their back as they dive beneath the surface, having come up to breathe. An adult can empty and refill its lungs very rapidly. As it surfaces from a dive, it exhales from two blowholes on top of its head. The air cools rapidly, forming a cloud up to 4 metres high, known as a 'blow'. If you're close enough, you can hear a very distinctive snorting sound: when this is very loud it's called a trumpet. Adults need to take a breath roughly every 10-15 minutes, although they can stay down for up to 45 minutes; calves need to come up for air every 3-5 minutes. When you're looking out for Humpbacks, the blow is very often the first evidence you see. Another clue are 'footprints' left behind when whales dive. These are circular areas of smooth water formed when a vortex is created by a whale's tail as it moves just below the surface of the water.

We saw other wildlife on Moreton. Upon arrival at Tangalooma there was a seabird reception committee on the beach, the cormorants busy drying their wings.
As we walked towards the resort to get breakfast we came across some birds we hadn't seen before – Bush Stone-curlews. They had an implacable air about them. They stood impassive in the gardens even when people passed quite close by, and yet seemed nervous when in a group on the beach, away from the safety of ground cover I suppose. Their legs are long and spindly although their knees are thickened, and they exhibit a bizarre sitting position, with their knees folded the wrong way.
In a funny kind of way they reminded me of meerkats, and I love the way they stand with one leg bent as if they're gossiping over the fence. These ground-feeding and ground-nesting, normally woodland birds are unfortunately endangered in many parts of mainland Australia. But I believe it may have been their blood-curdling night-time cries that kept us awake in Port Douglas.
And we saw an old friend...
And then some more.


But the Humpbacks stole the show. They are the only whales with long pectoral fins, or flippers: sometimes they use them to slap the water. We didn't see this but we did spot tail slapping, which may be part of a courting ritual, or a warning, or related to feeding. The underside of the tail, or fluke, is white with black markings, the pattern of which is unique to each whale and is thus used to identify individuals. Other distinguishing features of the Humpback's body are throat grooves, nobbly bits on their heads and flippers, and a very small dorsal fin, which you see as they arch.
Their only predators are Killer Whales, which in fact belong to the oceanic dolphin family and prey on whale calves in particular... and, of course, the Japanese, who claim to kill Humpbacks for 'scientific' purposes and are unabashed by global condemnation of their actions.

I wasn't prepared to lose a second of any Humpback action while fiddling with a camera, so I don't have any pictorial evidence. My friend, however, armed with a better zoom and keener eyesight, did catch these wonderful creatures on camera.

Humped back + footprints
A hump and a fluke



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