Whale watching has become a booming $1 billion-a-year industry, bringing a new, generally eco-friendly form of income to many cash-strapped areas around the world, according to a report released yesterday by the Massachusetts-based International Fund for Animal Welfare. By 1998, whale watching was going on in about 500 communities in at least 87 countries, up from just 31 communities in 1991. Countries that have only recently gotten into the game include Namibia, Oman, and Fiji, as well as Iceland and Japan, which have long histories of whale hunting. “Whales are worth a lot more live than they are dead,” says Karen Steuer of IFAW. Still, marine biologists warn that whale watching must be done the right way so as not to harass or injure marine animals.