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Marine Mammals - The Marine Mammal Protection Act, The Endangered Species Act, Whales, Dolphins And Porpoises, Seals And Sea Lions

Marine mammals live in and around the ocean. They are warm-blooded, breathe air, have hair at some point in their lives, give birth to live young (as opposed to laying eggs), and nourish their young by secreting milk. Dolphins, whales, seals, sea lions, walruses, polar bears, manatees, and dugongs (manatee relatives) fall into this category.

Historically marine mammals have garnered a high level of public support and legal protection. During the 1960s the television show Flipper entertained American audiences with stories about a highly intelligent and love-able dolphin that befriended and helped a family. Such tourist attractions as Marineland in Florida and SeaWorld in California began featuring acrobatic dolphins and whales in very popular shows. The growing environmental movement seized on the public interest in marine mammals and lobbied for measures to protect animals that many people believed to be extremely smart and sociable.

At the time purse-seine fishing was widely practiced by commercial tuna fishers in the eastern tropical Pacific Ocean. This fishing method involved the use of enormous nets, often hundreds of miles long that were circled around schools of tuna. Many dolphins were inadvertently captured because they tend to mingle with fleets of tuna in this part of the ocean. Nontargeted animals captured during commercial fishing activities are called "bycatch." Dolphin bycatch became a major public issue. Hauling in the enormous tuna-filled nets was a lengthy process. As a result, the air-breathing dolphins were trapped for long periods under water, and often drowned. It is estimated that more than 400,000 dolphins and porpoises died per year in this manner during the late 1960s. Public outcry over these killings and general concern for the welfare of marine mammals led the U.S. Congress to pass the Marine Mammal Protection Act of 1972.

Additional Topics

Marine Mammals - The Marine Mammal Protection Act

The Marine Mammal Protection Act (MMPA) was passed in 1972 and substantially amended in 1994. The original act noted that "certain species and population stocks of marine mammals are, or may be, in danger of extinction or depletion as a result of man's activities." However, it was acknowledged that "inadequate" information was available concerning the population …

Marine Mammals - The Endangered Species Act

As shown in Table 2.1 in Chapter 2, there were only three marine mammal species on the first list of native TABLE 5.1 Endangered and threatened aquatic mammals, February 2006 Adapted from "Listed U.S. Species by Taxonomic Group," in Threatened and Endangered Species System (TESS), U.S. Department of the Interior, U.S. Fish and Wildlife Service, February 10, 2006, http://ecos.fws.gov…

Marine Mammals - Whales

Whales are cetaceans, or marine mammals that live in the water all the time and have torpedo-shaped, nearly hairless bodies. (See Figure 5.1.) There are approximately seventy known whale species. The so-called "great" whales are the largest animals on Earth. In general, the great whale species range in size from thirty to 100 feet in length. There are thirteen whale species normally …

Marine Mammals - Dolphins And Porpoises

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 …

Marine Mammals - Seals And Sea Lions

Seals, sea lions, and walruses are considered pinnipeds. This designation comes from the Latin word pinnipedia, which means "feather or fin foot." Pinnipeds have fin-like flippers. Although they spend most of their time in the ocean, pinnipeds come on shore to rest, breed, give birth, and nurse their young. Areas preferred for breeding, birthing, and nursing are called rookeries. Pin…

Marine Mammals - Sea Otters

Sea otters are the smallest marine mammals in North America. They are furry creatures that grow to be about four feet in length and weigh up to sixty-five pounds. Otters are related to weasels and mink and are members of the Mustelidae family. Sea otters are almost entirely aquatic and inhabit relativly shallow waters along rocky coasts of the North Pacific Ocean. They eat a wide variety of marine…

Marine Mammals - Manatees And Dugongs

Manatees are large stout mammals that inhabit fresh waters and coastal waterways. They are from the Sirenian order, along with dugongs. There are only five Sirenian species, and all are endangered or extinct. Scientists believe that Steller's sea cow, the only species of cold-water manatee, was hunted to extinction during the 1700s. The West Indian manatee, also known as the Florida manatee…

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