thar she blows!

by Rod McQueen

Though I'm an old hand at whale-watching now — for two years in a row I have had the opportunity of spotting a few Megaptera novaeangliae, or humpback whales, off the NSW coast at Merimbula during their annual southward trek — I believe the thrill of watching these leviathans ply their cetacean trade could never wear off. (One species down, only about 35 more to go!)

In 2006, Martha and I did the tourist bit and booked a ticket on an expensive whale-watching safari. Since some friends who had gone fishing the day before had been treated to the magnificent spectacle of a number of whales leaping and frolicking, we set out with great expectations. Though we were disappointed at the meagre results — we saw only the backs and tails, from a considerable distance, of a mother and calf who were stubbornly disinclined to perform any balletic leaps — the disappointment was tempered by the zing that accompanies the first sighting of one's life. For about an hour we tracked the duo as they deliberately moved ever so slowly towards Antarctica and its tons of tucker. A few times we were treated to the sight of the calf lunging half-heartedly from the water before returning with a gracious splash.

Since the individuals we saw were hugging the coastline closely, probably no more than 100 metres from the shore, I decided that this year I would do my whale spotting from clifftops with a pair of binoculars. Well, I saw quite a few specimens this time, but all were stubbornly determined to stay hundreds of metres offshore. And once again, no sign of tail slapping or breaching (leaping). Foiled again. Oh well, better luck next time. And now that we have been bitten by the whale bug, numerous 'next times' there will be.

As I found from experience, the first visible evidence of a whaleberg passing by is usually the universally-recognized spout of tiny water droplets, the shape of which differs by species, followed shortly thereafter by a vignette view in slow motion of the tip of the back as it breaks the surface, glides along, then sinks back in a steep arch into the depths with an upward flick of the massive tail before disappearing from sight. Most of the time that's all you get to see. Very modest creatures, these acrobatic giants. Either that, or they love taunting hopeful observers. If you are truly lucky, as my fishing friends were, you may witness the spectacular behaviour known as breaching — a full-on leap from the water during which they roll in the air with their huge fins outstretched like wings, followed by a thunderous and dramatic return crash. Though experts differ as to the purpose of this phenomenon, they can tell you with assurance that such leaps constitute 'the most powerful single action performed by any animal' (Hal Whitehead, 'Why Whales Leap', Scientific American, March 1985), entailing the lifting of a biomass equivalent to about 485 people weighing 68 kgs each. These gentle giants are also known to lift their pectoral fins out of the water and wave them about as well as to roll over and smack the fin down on the surface.

One of about 76 species of whales and dolphins of the mammalian order Cetacea, the humpback whale belongs to the suborder Mysticeti, or baleen whales. This suborder includes the grey whale, right whales (three species) and the rorquals (six species, including the humpback). These beasts sieve out small organisms such as krill from the water using combs of baleen plates made up of thick bristles suspended from the upper jaw on both sides of the mouth. Wikkipedia informs us that the largest of these sets of plates can measure up to 3.5 metres long and weigh as much as 90 kgs. The other suborder of whales, the Odontoceti, includes toothed species such as dolphins, white whales, sperm whales, and beaked whales.

The humpback whale, noted for the huge pectoral fin which can attain lengths of up to one third of its 16 metre body length, is found in all the world's oceans. Females give birth in tropical waters where the warmth provides suitable conditions for the calves to feed and put on a layer of fat before heading towards the colder poles for their summer orgy of eating. Despite their enormous size, humpback calves are born without a protective blubber layer and would quickly freeze to death in frigid waters. Growth is rapid as calves drink 400 litres of mother's milk — which is about forty times fattier than human milk — every day. The conflicting needs of warm waters for the survival of the newborn and cold waters for the provision of enormous amounts of food explain their annual migration. Humpbacks hold the record for mammalian migration; one individual was found 8000 kilometres removed from a previous sighting five months earlier. Only in the Arabian Sea do you have a year-round population that defies this general pattern.

Eastern Australian humpbacks spend the winter off the Queensland coast and the summer in cold Antarctic waters where the direct rays of the sun maintain huge populations of photosynthesising diatoms and their predators, including the 4 to 8 cm shrimp-like krill that makes up the lion’s share of the humpback's diet. (Humpbacks also eat whatever else, including fish that their baleen plates sieve out.) They can best be seen during the southbound leg of their annual pilgrimage between late September and late November, the peak time for viewing along southern NSW's Sapphire Coast being late October. At this time mothers and new-born calves are often seen together, and individuals are more inclined to travel in groups than during their northward autumn migration.

Whaling was Australia's first primary industry; oil was used in lamps and candles and as a base for perfumes and soaps. Baleen was used in corsets, whips, and umbrellas. By 1845, twenty six thousand whales had been killed in eastern Australian waters, most of which were southern right whales. Few humpback whales were taken by comparison; hunting them in earnest began in eastern Australia around 1950. In typical who-cares-about-tomorrow style, they were pursued so relentlessly and efficiently that by 1962 over 12,500 had been killed and processed leaving only 200 to 500 survivors; the industry collapsed due to its own stupid success. Since 1965, when they became protected, numbers have been steadily increasing, so that now about 8000 are estimated to pass along the coast, with the number increasing by about 10% each year. Although that's still a long way short of the estimated 30,000 that once took part in the annual migration, it's enough to ensure any determined person with a pair of binoculars and an hour to spare at least a glimpse of this majestic creature.

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