Endangered Species Handbook

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Aquatic Ecosystems

Noise, Boat Collisions and Debris

     The once quiet oceans now rumble with huge cargo, cruise and naval ships whose noisy engines drown out the delicate rumblings, and songs whales make to establish territory and communicate, as well as the myriad sounds other creatures emit in the ocean depths vital to their survival.  The North Atlantic, Mediterranean and Baltic are especially busy shipping lanes.  Wildlife now has new and lethal noises to cope with.  The Navy has been testing anti-submarine sonar called Low Frequency Active.  Powerful sonar waves are broadcast underwater to test a means of detecting quiet enemy submarines (White 2000a).  These sonar waves can travel hundreds of miles and be extremely loud.  Humpback whale (Megaptera novaeangliae) males emitting their complex, haunting songs to establish territory have become silent or moved away when these waves were broadcast.  More ominously, testing in 1995 off the coast of Greece coincided with an unusual stranding of Cuvier's beaked whales (Ziphius cavirostris) resulting in the deaths of these seldom-seen whales.  In March 2000, Ken Balcomb, a biologist from the Center for Whale Research who is familiar with sonar, was present when a stranding occurred while Navy tests were taking place nearby.  Fifteen animals stranded, including dense beaked whales (Mesoplodon densirostris) and other species of beaked whales, a Minke whale (Balaenoptera acutorostrata) and a spotted dolphin (Stenella frontalis).  All washed up on the shores of a Bahamian island; when pushed back into deep water, they were unable to remain upright, clearly unbalanced and disoriented, and nine died (White 2000a).  Along with Harvard biologist Darlene Ketton, Ken Balcomb performed necropsies on several whales, finding their ears full of blood and, in one case, hemorrhages striped the lungs; further testing discovered that a whale had suffered a concussion, apparently the result of acute trauma from pressure (White 2000a).  A press conference organized by the Animal Welfare Institute following these findings featured Ken Balcomb and other whale experts, who attested to the fact that the sonar is reckless, unnecessary and lethal to whales.  Soon after, the Navy canceled testing of active sonar off New Jersey, as well as its scheduled tests on sperm whales in the Azores (White 2000).  This technology fills the ocean with penetrating sound waves that greatly disturb or kill marine mammals, interfering with their own sonar and natural behavior.
 
     A major cause of mortality for Florida manatees is collisions with boats. Manatees struck by motorboats or their propellers can be killed instantly, or may suffer slow, painful deaths from deep slashes and internal injuries.  In some cases, these strikes have been intentional.  CNN recently reported a case of a woman who witnessed a young man in a motorboat repeatedly driving over a mother manatee and her calf until both were dead.  She called the state law enforcement division, but by the time officers arrived, the perpetrator was gone.  Many calves are orphaned when their mothers are killed, and only if they are found within hours can they be rescued and cared for by Sea World or other aquariums in Florida.  In the first half of 2000, the state determined that 61 deaths were caused by watercraft, just short of the all-time high of 67 for the entire year of 1999.  These figures may be lower than the actual mortality, since some manatees may be struck and sink, while others, whose bodies are found, may show no outward sign of injury, having been struck by the bow or side of a boat.  These collisions occur with such frequency that virtually all adult Florida manatees have propeller scars on their backs.
 
     The present system of posting speed limits has not been effective in reducing collisions, since so many boaters refuse to obey them and enforcement is inadequate.  Manatees swim long distances to find warm water during the winter, passing through shipping lanes and most of southern Florida's navigable waters.  This creates a problem that the State of Florida and the Fish and Wildlife Service have not properly addressed, yet one that must be solved to preserve this species.  Apparently, manatees do not hear motorboats coming.  Research is taking place on the placement of some type of noisemaker attached to the underside of boats to warn them.  Even this would not result in a halt to all manatee-boat collisions, however, because these animals are too slow-moving to avoid high-speed boats.  Boat propeller guards would also reduce manatee deaths and injuries, as well as human injuries caused by accidents with these sharp blades, but they have not been required by law.  The number of pleasure craft in Florida has risen exponentially in recent years, with few laws and regulations governing those who propel them, such as strict regulations on sobriety and competence to handle the boats.  Heavy boat traffic has also resulted in human fatalities and injuries from collisions. 
 
     Two lawsuits were filed in January 2000 on behalf of the Florida manatee.  A coalition of 18 environmental and animal welfare groups, led by the Save the Manatee Club, sued the State of Florida, the US Army Corps of Engineers and the US Fish and Wildlife Service.  The Animal Welfare Institute's companion organization, the Society for Animal Protective Legislation, has worked with the coalition's legislative team to obtain $500,000 from the Congress for manatee protection.  The corps was sued for its repeated issuance of permits for development in manatee habitat without analyzing the cumulative effects of the permits on the species or its habitat.  The suit charges the Fish and Wildlife Service with failure to properly enforce the Marine Mammal Protection Act of 1972 and the Endangered Species Act to prevent mortality and to conserve the species.  The US Fish and Wildlife Service failed to designate adequate sanctuaries for manatees where boat traffic would be restricted, reducing its proposed list of sites from 150 in Florida to 10 to 15 (Daley 2001).
 
      The second suit was filed against the Florida Fish and Wildlife Conservation Commission, which has not complied with the Florida Manatee Sanctuary Act of 1978, enforced speed limits, or taken other measures designed to protect these vulnerable animals.  The mortality rate from all causes is far greater than the number born, pushing manatees toward extinction.  Florida Governor Jeb Bush angered conservationists in late 2000 by allowing the licensing of more boat slips in Sarasota, although the county had not completed a required plan to protect manatees (Daley 2001). 
 
      The future is bleak for the approximately 3,000 surviving Florida manatees unless dramatic action is taken (Daley 2001).  Their survival has become critical.  Other causes of mortality, such as death from red tide, pollution or cold weather, add to the toll.  In 2000, for example, 273 manatees died from all causes, close to 10 percent of the entire population (Daley 2001). Since manatees have a single young only every 5 to 7 years, they cannot sustain such losses.  These gentle and affectionate animals have been on Earth for 45 million years, yet a lack of concern and willingness to alter our recreational boating habits may eliminate them in Florida.  Elsewhere in the range of these manatees, far stricter regulations have been imposed on boat traffic.  In Belize, for example, very few manatees have boat propeller scars because many areas are off-limits to all motorized boats, and tours are conducted in boats propelled by poles.
 
     There are two major threats to whales and marine mammals causing their elimination in many areas.  Fishing vessels throw out ropes, nets and other debris that entangle marine mammals, often lethally, and vessels of all types present the danger of mortality through collisions.  One or more highly endangered North Atlantic right whales (Eubalaena glacialis die each year from rope and net entanglements or collisions with ships; their population is only at about 300.  In 1995, a whale of this endangered species became wrapped in lobster line and died off the Rhode Island coast.  In September 1997, another whale became hamstrung with nylon netting around his head, towing a 9-foot sea anchor near Nova Scotia; it took 8 1/2 hours to free him, after a 25-kilometer chase by a rescue team.  A young blue whale (Balaenoptera musculus) was killed when a ship collided with it; the ship entered a Massachusetts port with the whale impaled on its bow.  In early 2001, three dead fin whales (Balaenoptera physalus) washed ashore along the Atlantic coasts of the United States, killed by ship collisions.  For North Atlantic right whales, such collisions may end in their extinction, unless means are found to prevent them.  These whales have a single calf only once every five years and are dying at such a rate that scientists expect their extinction within less than a century.  
 
       Plastic bags and fishing gear have been found to strangle and suffocate endangered sea turtles, marine mammals and sea birds.  Endangered albatross on Laysan Island are among the many species to have died after ingesting plastic materials.  They also feed their chicks plastic items they mistake for food, unintentionally killing them.  Sea turtles, dolphins, whales and sea lions around the world are drowning and strangling in fishing lines and nets.  One endangered fin whale that washed ashore dead in Biscayne Bay, northern Spain, in 1997 was found to have ingested huge amounts of plastic sheeting and bags that clogged its digestive system.   Each year millions of balloons are released to the winds, and untold numbers end up floating in the oceans, a peril to wildlife.  One young sperm whale (Physeter catodon) starved to death after swallowing a single balloon that blocked its intestine.  Endangered sea turtles die after consuming plastic bags and balloons, mistaking them for jellyfish.  Non-biodegradable plastics and nylon nets and ropes in the ocean will present lethal threats to wildlife for the indefinite future.  Although international treaties have been signed that regulate such dumping, to date no national or international program has attempted to remove debris, such as plastic items, nets and fishing lines, from the oceans.


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    ©1983 Animal Welfare Institute