IN THE SEASON of 1937 and 1938, the world whaling industry killed almost 55,000 whales. Most of their oil went into margarine, their meat into pet food. It was an orgy of killing that far surpassed any previous record, and it followed a decade of negotiations on how to limit the hunt. But these were token and cynical efforts: negotiators set minimum lengths large enough so that immature whales could still be taken, and banned whaling except in the places where most of it took place. It took a world war`s appetite for ships to slow the hunt, and then it resumed when the war ended. A History of World Whaling (Viking, 288 pages, $29.95 cloth) is readable, well researched and, of course, depressing. The author, Daniel Francis, concludes by insisting that it is no longer enough to stop killing whales. The numbers of many species are so reduced that they are even more vulnerable to the pollution we inflict upon them. The same romantics who bled for the plight of three grey whales recently trapped in the Beaufort Sea`s ice -- a natural hazard and one the species can well survive -- go on letting their cities and industries continue polluting, the St. Lawrence. Meanwhile, the river`s everdwindling population of beluga whales continues to die of things like perforated ulcers, cancers, blood poisoning, and abscesses of the lung. A History of World Whaling shows that we have to change our ways.