Compared with the more intractable problem of overfishing, technological solutions to bycatch abound.Bycatch ensnares coral, sponges, starfish, sharks, whales, turtles and even birds. It is "one of the more immediate threats that marine diversity faces," Werner says. It has led to the assumed extinction of the Yangtze River dolphin, has nearly wiped out the Gulf of California's vaquita porpoise (fewer than 200 remain), and threatens the survival of the North American right whale (400 remain) and the short-tailed albatross. A United Nations report estimates bycatch at 7.5 million tons a year, or 5 percent of the total commercial-fishing haul. Because most available data is self-reported, Werner says that the U.N.'s numbers "woefully underestimate" the problem. A more representative statistic, he says, comes from Gulf of Mexico shrimp fisheries, some of which dredge up to five pounds of bycatch for every pound of shrimp.