The humpback whale

Twice a year the best conservation news on this coast swims past in plain sight. Each winter the humpback whales of eastern Australia run north to breed and calve in the warm tropics; each spring they stream south again, often with a calf at the flank — a procession of great animals so close, and so reliable, that it has become one of the region’s finest spectacles. They pass near the shore for a reason of geography: the land does not stop at the beach. Its slope carries on down a narrow continental shelf, and the coast’s headlands crowd the migratory lane so close that you can read the whole highway from the rock.

But the spectacle is the easy part. The harder question is what a humpback actually depends on — and the answer is nothing you can circle on a map. It is a journey, one of the longest and most reliable any animal makes. The whale fattens through the southern summer in cold, krill-thick water near Antarctica, breeds and calves in the tropics thousands of kilometres north, and needs the long road between the two kept open and unharried. That is the reverse of how the coast’s great specialists live. Where the koala is staked on one leaf and the dugong on one meadow, each undone by the loss of a single narrow thing in a single place, the migrant is staked on a corridor, and so lies exposed along its entire route: to the net, the hull, the underwater roar of engines and a warming ocean, anywhere between the ice and the reef. The corridor is a piece of moving water animals merely pass through, and it respects no line on any chart. That is what makes minding a whale so much harder than fencing a paddock.

And within living memory the humpback was undone by the crudest pressure of all. It was simply killed. The whaling station at Tangalooma, on nearby Moreton Island, took 6,277 humpbacks between 1952 and 1962, before the whales ran out and the station closed. By then the entire eastern-Australian population had been driven down to a few hundred animals hanging on. That is how close it came: an animal that moves in tens of thousands reduced to a remnant you could almost have counted by hand.

Then it turned around. Protected from whaling in 1963, the population climbed, decade on decade, back into the tens of thousands. Recent assessments put it at something like forty thousand, at or above where it stood before the killing began, and the humpback highway off this coast once again ranks among the densest gatherings of great whales anywhere on Earth. A few hundred animals to forty thousand: you cannot argue with a graph like that.

Read as a dependence, the lesson is unusually clean. This animal did not need a vaccine, or a fragile habitat mended thread by thread, or a captive-breeding programme, or any of the delicate, uncertain repairs the rest of this coast’s conservation runs on. It needed one thing to stop happening to it. Lift the single fatal pressure, and a great animal that was all but gone will, given only a few decades and the run of the sea, fill the water again. On a coast where most of the news runs the other way, the whales are the exception, and twice a year you can stand on a headland and watch them go by.