Now some happy news from the ocean: blue whales have been spotted in migratory routes and feeding grounds in the Pacific that has been void of blue-whales for over half a century. Sightings are also increasing in the Atlantic, and recent research suggests that the Antarctic blue whale population is growing at a heartening 6% a year. About 440 blue whales have been spotted in the western Atlantic and about 200 in the eastern, including large numbers off Iceland. These are likely to be just a fraction of the total amount of blue whales present in these waters.

Bluewhale Blue whales are reclaiming their old feeding grounds

The overall numbers are still tiny compared with the original populations before whaling started, but the trend is at last in the right direction,” said John Calambokidis, a marine scientist whose research on whale movements and populations has just been published in the journal Marine Mammal Science. “This may represent a return to a migration pattern that existed in earlier periods for the eastern north Pacific blue whale population,” he said.

Richard Sears, founder of the Mingan Island Cetacean Study in Canada, has noticed a similar trend with blue whale sightings increasing in the north Atlantic during the past few years. Sears is cautiously optimistic, but warns that the increase in sightings may be partly due to more people looking for whales. “There is still no room for complacency,” he said.

Until the 20th century, blue whales were normally avoided by whalers since these oceanic giants were too large and too fast for traditional ships to handle. With a maximal reported length of over 30 meters and the capacity of exceeding 170 metric tons in weight, the blue whale is the largest animal even known to have existed on our planet and capturing it using an old fashioned sailing vessel is certainly no picnic.

Before the invention of the steam-powered whaling ship and the exploding harpoon, the estimated global population of the blue whale was somewhere between 350,000 and 400,000. By the 1960s, no more than 5,000 blue whales were left.

Unlike whales such as the humpback which has undergone a remarkable recovery since the international ban on whaling was imposed, the blue whale populations have not shown any clear signs of recovery during the last few decades and scientists have worried about them being too shattered and fragmented to be viable populations in the long run. Illicit harvesting has also been a problem – files handed to the International Whaling Commission by Alexey Yablokov, environmental adviser to Boris Yeltsin, showed that the Soviet Union killed over 9,000 blue whales from the time of the ban until 1972.

These revelations go some way towards explaining why blue whale populations stayed low for so long,” says Dan Bortolotti, author of the book Wild Blue. “It also suggests that they may now have a chance to recover — but only if the ban on hunting all large whales stays in place.”