National Geographic : 2008 Oct
success. Fertile adult females are the most valu able segment of the population. They number fewer than a hundred. Calvin seemed on the verge of adding one more to their ranks. For three years running, the researchers gauged the young female's blubber thickness with ultrasound. It's a tricky operation. "One whale's reaction jolted the skiff hard enough to send me flying overboard," Amy Knowlton of the research team recalled. Nevertheless, the researchers found Calvin growing pleasingly plump, a prime measure of health. On New Year's Eve of 1999, she was recorded for the first time in the Georgia Bight, an expanse of shallow coastal waters off Georgia and Florida, where right whales give birth. In summer of 2000 Calvin was once again in the Bay of Fundy, but this time she was snarled in fishing gear. Unbreakable polyblend ropes wrapped round her body, cut into the skin, and trailed in her wake, slowing her down. Then researchers lost sight of the young female. Two to six right whales are found dead in a typical year, at least half of them killed by ship strikes or entanglement. Additional ani mals simply disappear. Since more than three quarters of North Atlantic right whales bear scars from encounters with fishing gear, sci entists wonder: How many of those missing are weighed down by ropes, nets, or crab and lobster pots for months or even years, the fat reserves that help keep them buoyant dwindling as they starve, fighting harder to reach the sur face for each breath, until they finally give in to pain and exhaustion and sink? Months dragged by. Someone finally spotted Calvin in Cape Cod Bay during her hobbled journey back south. A disentanglement team from nearby Provincetown, Massachusetts, raced for the site and made two attempts to slice away her bindings. They couldn't get them all, but when Calvin was seen during 2001, she had worked free of the remnants. Three years passed, and Calvin showed up MAKING AHOME INDANGEROUS WATERS North Atlantic right whales run a gantlet of ships, nets, and lines as they swim through a bustling mari time corridor, feeding, giving birth, and raising young. Conservationists say limiting vessel speeds to ten knots in key areas when whales are present would cut ship-strike mortality dramatically. Researchers are also working to develop fishing lines that would break rather than entangle and kill whales. Prevent ing all human-caused deaths could swell the population an estimated 25 percent within 15 years.