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Its amazing and a must for marine mammal fanatics. Contains all you need to know, is written my many researchers and includes references for further reading. Shane rated it it was amazing Jul 13, Peter rated it really liked it Apr 25, Michelle rated it it was amazing Feb 04, Vivian rated it it was amazing Aug 21, Brian Beatty rated it it was amazing Oct 10, Erich rated it it was amazing Dec 08, Leon Maxwell rated it liked it Jan 11, Robert Hult rated it it was amazing Sep 08, Natalia Botero Acosta rated it it was amazing Mar 30, Danielle Brown rated it it was amazing Mar 10, Justin Gregg rated it it was amazing May 04, Vikie Pedneault rated it it was amazing Aug 07, Isma rated it really liked it Jan 15, Iranica added it Aug 13, Magic3 added it Apr 09, Elizabeth marked it as to-read Aug 02, Brecken marked it as to-read Apr 01, Stephanie Cook marked it as to-read Aug 25, Wikimedia Italia added it Dec 31, Lauren marked it as to-read Jan 19, Carmen Reyes marked it as to-read May 31, Minakhus Sania added it Sep 14, Julie added it Dec 30, Maria Jose marked it as to-read Aug 16, His work with the sense organs of modern whales explores the impact of global change on marine mammal populations.
A native of the Netherlands, he holds degrees in biology and geology from the University of Utrecht and the University of Michigan and teaches anatomy and embryology to medical students at Northeast Ohio Medical University. Encyclopedia of Marine Mammals W. Encyclopedia of Marine Mammals Bernd G.
Encyclopedia of Marine Mammals Gale virtual reference library. All of these whales are considered "great" whales.
All but the sperm whale have baleen plates. Surveys of all species are not conducted every year. Summing survey results from each report provides a rough estimate of the minimum population of each species:. The NMFS notes that sei whale populations are extremely difficult to estimate. The whales prefer the open sea and rarely enter U. Also, they tend to travel alone or in small groups, making them difficult to count.
Encyclopedia of Marine Mammals
The northern right whale is also known as the North Atlantic right whale because it is primarily found along the eastern coast of the United States. Although a few sightings have been confirmed in the North Pacific Ocean, there is no official estimate of that population. The National Marine Fisheries Service considers both populations to be of the same species. However, this opinion is disputed by some scientists.
The northern right whale is the most endangered of the great whales. It was once the "right" whale to hunt because it swims slowly, prefers shallow coastal waters, and floats upon death. The species was nearly driven to extinction by whaling, which was banned in when the population had been reduced to an estimated Despite decades of protection, the northern right whale population has not recovered, and as of the WWF estimated no population increase at all since the s. Some scientists believe the animal is in grave danger of becoming extinct within only a few decades. Whale populations are imperiled due to a long history of hunting by humans.
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As early as the eighth century, humans hunted whales for meat and whalebone baleen. Whales were relatively easy for fishermen to catch because the animals spend a great deal of time at the surface of the water and provide a large target for harpoons. Advances in shipbuilding and the invention of the steam engine allowed fishermen greater access to whale populations, even those in Arctic areas that had previously been out of reach.
By the nineteenth century, large numbers of whales were being killed for blubber and baleen. Blubber was rendered to extract whale oil, which was used to light lamps. Baleen was valued for making fans, corsets, and other consumer goods. The IWC was formed as a means to regulate the industry and limit the number and type of whales that could be killed. As of February there were sixty-six member nations in the IWC. Centuries of whaling severely depleted whale populations.
Low birth rates and high mortality rates due to a variety of factors have prevented many species from recovering. Like other marine animals, whales are endangered by water pollution and loss or degradation of habitat. However, the biggest threats to the northern right whale are believed to be entanglement in fishing gear and ship strikes.
The article describes recently published research related to whale entanglement. According to studies conducted in by the New England Aquarium, In researchers from Duke University investigated thirty-one cases of right whale entanglements and tried to identify the type of fishing gear involved in each case. They found that nearly a third of the whales had become entangled in lobster pot gear, mostly buoy lines. It was concluded that any type of fishing line that rises vertically in the water column poses a "significant entanglement risk" to northern right whales. As shown in Figure 5.
Encyclopedia of Marine Mammals | Journal of Mammalogy | Oxford Academic
East Coast between and Strikes on northern right whales are particularly troublesome because so few of the animals remain in existence. According to the NMFS fourteen northern right whales were confirmed killed by ship strikes between and Figure 5. Most strikes in U. These areas are near or within critical habitats designated by the National Marine Fisheries Service for the whales. The southern critical habitat is the only known calving area of the northern right whale and is used from mid-November to mid-April.
During calving season the NMFS performs aerial surveys and alerts ships about whales in their vicinity. In addition, federal law requires that ships remain yards from right whales. Any sightings of dead, injured, or entangled whales must be reported to authorities.
In January the NMFS announced that a dead right whale calf had been reported by a fishing crew near the Florida shore. The animal was towed to shore and found to have large propeller marks and other wounds on its body, indicating it had been struck by a ship.
Encyclopedia of Marine Mammals
The whale was male and only one month old. In the National Marine Fisheries Service announced plans to propose rules requiring routing changes and speed limits for large vessels traveling in U. The agency was still developing the rules in May when several environmental and animal groups petitioned the NMFS requesting that a temporary emergency regulation be imposed until the permanent rules could be issued. The petitioners asked for a speed limit of 12 knots Two months later, three of the petitioners—the Defenders of Wildlife, the Humane Society of the United States, and the Ocean Conservancy—filed a lawsuit against the NMFS accusing the agency of "failing to protect" northern right whales as required by law.
The lawsuit had not been resolved as of early , when the petitioners filed papers that added the U. Coast Guard as defendants in the suit for their failure to adequately protect the whales in U. As of February no recovery plans had been developed for bowhead or sperm whales. A draft recovery plan was published in for fin and sei whales and is undergoing revision.
A recovery plan for the Pacific population of the northern right whale is under development. Final plans have been published for the blue whale , humpback whale , and the Atlantic population of the northern right whale Priority numbers can range from a value of 1 highest priority to 12 lowest priority.
The northern right whale has a priority level of 1, indicating strong concern about its abundance and chances for survival as a species. The recovery plan for the North Atlantic right whale lists five goals for recovering the species. In order of importance, the goals are:.
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Dolphins and porpoises are toothed cetaceans. They are similar in shape; however, dolphins are generally larger than porpoises and prefer shallower, warmer waters. Dolphins tend to have long bottlenoses and cone-shaped teeth, as opposed to the flatter noses and teeth found in porpoises. Porpoises are members of the Phocoenidae family, which includes only six existing species. Dolphins are members of the Delphinidae family, a large family containing at least thirty known species.
Most dolphin and porpoise populations around the world are hardy and not in danger of extinction. However, there are several species that are in trouble due to limited geographical distribution.