Navy sonar and whale strandings – 04/14/2006

  • November 23, 2013 at 2:58 pm #1177

    from caraway

    Collateral Damage
    News: Navy sonar exercises could be to blame for whale strandings.
    By Dick Russell
    March 1, 2006

    The pilot whales began coming ashore last January, on North Carolina’s Cape Hatteras National Seashore, not far from Whalebone Junction, where fishermen make the turn toward the marina at Oregon Inlet. Short-finned with distinctly rounded heads and long, stocky dark bodies, some were almost 20 feet long, weighing up to three tons. By the time they were discovered in the surf near a lonely five-mile stretch of beach, 15 pilot whales—6 of them pregnant—were dead. Seven more had to be euthanized by veterinarians. During the next two days, a newborn minke whale and two dwarf sperm whales also died in one of the largest beaching events ever documented along this coastline.

    Scientists arrived to gather tissue; after the necropsies, the whales were buried on the beach. “It’s curious to have three different kinds of whales strand, and a number of possible causes are being examined. Sonar is certainly one of them,” said Connie Barclay, spokeswoman for the National Oceanic Atmospheric Administration.

    On the day the strandings began, several Navy ships conducted submarine-hunting exercises off North Carolina’s Outer Banks, using loudspeakers to send mid-frequency sonar sound waves across ten or even a hundred miles of ocean. Sonar devices can locate an enemy’s sophisticated, almost-silent diesel submarines by, ironically, making a deafening noise—sometimes above 230 decibels, as loud as a Saturn V rocket blasting off. (Underwater noise of only 120 decibels—a level billions of times less intense—has been known to disrupt whale behavior.)

    The Navy maintains that the sonar training had nothing to do with the whale strandings, but it has been forced to acknowledge such problems in the past. In 2000, 16 whales, of three species, beached themselves along a 150-mile stretch of the Bahamas; whales and porpoises have also come ashore and died on five different occasions on the Canary Islands, as well as along the coasts of Greece, Spain, and Alaska. Each time, sonar exercises were being conducted by the U.S. Navy or NATO forces nearby. In a 2004 report, the Scientific Committee of the International Whaling Commission found that the evidence linking Navy sonar and whale strandings “appears overwhelming.” In November, a U.N. report concurred that increased naval military maneuvers and sonar are harming the ability of 71 types of whales, dolphins, and porpoises to communicate, navigate, and hunt.

    Nor, as once thought, does the sonar simply misdirect the animals to beach by interfering with their echolocation. Scientists have detected severe lesions in organ tissue, bleeding in the brain and from the ears, and indications that the whales have been literally shaken apart by the intense sound. The journal Nature has reported that the victims of one mass stranding exhibited strange gas bubbles in certain organs. This has led researchers to conclude that the whales may have suffered a kind of decompression sickness similar to “the bends,” known to kill human divers who surface too quickly. Pilot whales and dwarf sperm whales dive more than 1,000 feet deep to feed off the slopes of the continental shelf such as those off of North Carolina. The whales at Cape Hatteras may have panicked and come up too fast.

    Yet now, roughly 60 miles farther down the Carolina coast, the Navy plans more than 160 sonar exercises annually across a 500-square-mile area at a new Undersea Warfare Training Range. The Navy has pledged to reduce sonar power should any marine mammals be spotted within 350 yards of its ships or 200 yards of helicopters towing sonar arrays—but that accounts only for animals on the surface, and some whales that died in the Bahamas are thought to have been tens of miles away from the sonar source.

    In 2003, the Natural Resources Defense Council (NRDC) got the courts to severely restrict the Navy’s plan to deploy a new low-frequency active (LFA) sonar system around the globe. The intensity level of LFA is basically the same as mid-frequency sonar, but because it operates in a lower frequency, it covers a lot more ocean. The Bush administration responded by pushing legislation through Congress that exempts the military from key provisions of the Marine Mammal Protection Act. In essence, the Navy can now choose whether or not to abide by the act. In October, the NRDC and several other conservation groups sued the Navy over mid-range frequency sonar, demanding that it “understand the environmental impacts of its actions, and to mitigate those impacts, before flooding vast areas of marine habitat with intense, harmful noise.”

    Whales’ ability to withstand this new variety of human onslaught remains very much an open question. Meanwhile, Japan, Norway, and Iceland continue to flout a 1986 inter- national moratorium on commercial whaling. In early November, a Japanese fleet left for Antarctica with plans to kill more than 900 minke whales and 10 endangered fin whales. Next year, Japan plans to kill 50 humpback whales. Whales are taken under the guise of “scientific research,” but the meat quickly reaches Japanese supermarkets and restaurants.

    And so, nearly 30 years after sending its little Zodiacs to confront Soviet whaling ships and sparking the environmental movement, Greenpeace is going back at it too, with plans to disrupt the Japanese whale hunt in the Southern Ocean.

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