Case Study: gray whale an
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- Range and Status
- Natural History
- Causes of Endangerment Commercial Whaling
- Commercial Fishing
- Coastal Development
- Conservation Actions Whaling Moratorium
- Protected Areas
- Directing Vessel Traffic
- Endangered Species
- Analysis Questions
C ase Study: GRAY WHALE
AN ENDANGERED SPECIES http://www.bagheera.com/inthewild/van_anim_grywhale.htm The gray whale is known as both the friendly whale and the fighting whale. Yupik Eskimos who hunt the gray whale in Alaska, and 19th century commercial whalers who hunted the gray whale in Mexico have each called it “devil fish” because of its reputation for fighting back and overturning boats when attacked. Today, gray whales are protected by law, and tourists who view them at their breeding and calving grounds in Mexico, regard them as friendly. The whales seem to be curious about these tourists and frequently swim up to their boats and allow the visitors to touch their barnacle-covered backs. The experience is thrilling and many people believe the whales enjoy it, too. The gray whale has the reputation as another kind of fighter, a fighter against the forces that would bring about its extinction. The species has fought its way back from the brink of extinction on two occasions. Like other large whales, gray whales were commercially hunted and their numbers were reduced to just a few hundred at two different times. The eastern Pacific population of gray whales has made a remarkable recovery as a result of legal protection. In 1995, this population was removed from the endangered species list. Unfortunately, other species of whales have not been able to recover as quickly as the eastern gray and most remain highly endangered. Range and Status The gray whale’s range formerly included the coasts of both the Atlantic and Pacific Oceans. The Atlantic population had been hunted to extinction by the 1700s and in the early 1900s it seemed that the two Pacific populations (eastern and western) would follow. However, in the 1940s the species became protected by international agreement, and today the eastern Pacific population has recovered so much that it is no longer considered endangered (although it is still protected). Population estimates indicate that there are more than 20,000 gray whales in the eastern Pacific, approximately equal to estimates of the historic population. The eastern Pacific population of gray whales was removed from the endangered species list in 1995, but the western Pacific (Korean) population, which has not recovered at all, remains listed. The status of the western Pacific population is relatively unknown, but it is believed to be highly endangered and close to extinction. The gray whale is an interesting case study because one population is extinct, one is endangered, and one is recovered. Natural History All whales are mammals, and they are more closely related to cows than to fish. They are warm-blooded, breathe air and give birth to live young. Adult gray whale females mate every other year and are pregnant for more than a year. The calves are born in January or February, and they can be up to 12 feet (4m) long and weigh 2,000 pounds (900 kg). Gray whales are bottom feeders, dredging the sandy ocean floor for amphipods, isopods, tubeworms, and other bottom-dwelling organisms. They are in the class of whales that have no teeth, called baleen whales. They eat by using baleen, a fringed plate that lines the upper jaw and traps prey in the mouth while water is filtered out. Most feeding takes place in their summer grounds in Alaska between May and September, and some feeding occurs during migration. Adults rarely feed while in and around their breeding lagoons in Baja California. The only animal known to prey on gray whales, other than humans, is the killer whale (Orcinus orca). However, an analysis of tooth scars on stranded gray whale carcasses indicates that these attacks frequently are not fatal. The eastern Pacific population of gray whales has the longest migration of any mammal, traveling up to 10,000 miles (16,000 km) round trip from the summer feeding grounds in the Bering and Chuchki Seas in Alaska to the winter breeding and calving grounds in Baja California. The trip takes about four months and the whales swim day and night, even while sleeping. They stay close to the coastline, and swim alone or in small groups. The migration is staggered according to age and sex, with pregnant females leading the way, followed by other females, adult males, and then immature females and males. On the way back north the migration is similar, with the newly pregnant females leading the way. Females with new calves bring up the rear. Although gray whales are protected throughout their range, they receive special attention at the breeding and calving grounds in Baja. In the 1970s, Mexico designated refuges in three of the four major lagoons the whales use. To prevent disturbance of the whales, boats are allowed to enter the lagoons only with a governments permit. The fact that gray whales congregate together in the winter for mating and calving has been partially responsible for both their difficulty and their recovery. In the 1800s, when commercial whalers discovered the calving lagoons, the concentration of whales in the shallow waters made their wholesale slaughter very easy. By the 1890s, the gray whale was almost extinct and most hunting stopped. In the 1920s, they were again commercially targeted, and once again, brought to the verge of extinction. There probably were only a few hundred individuals left when they were finally protected by international agreement in the 1940s. Since the 1940s, other protected whale species have languished near the verge of extinction, but the eastern gray whales’ population has increased steadily. Some scientists believe gray whales have fared so much better than other species because, despite their low population numbers, they have no trouble finding mates because they gather in the small lagoons, the same factor that once made their slaughter so easy. Causes of Endangerment Commercial Whaling Commercial whaling has been the main threat to all large whales. In the past, whale products included margarine, gelatin, shoe polish, cosmetics, paint, soap, glue, corset frames, lubricant, candle wax, lighting oil, and of course, whale meat. Many whale oil products were gradually replaced with cheaper petroleum-based substitutes as they became available. Commercial whaling is regulated by the International Whaling Commission (IWC), which voted to phase out all commercial whaling in 1982. Not all whaling nations agree with the ban, however, and the IWC’s ability to enforce prohibitions is limited. Norway withdrew from the IWC and resumed commercial exploitation of minke whales (Baleanoptera acutorostrata) in 1994. Both Norway and Japan kill whales for scientific purposes, although many observers believe that the true purpose of this continued whaling is commercial use. Whale meat now sells for about $300 per pound ($136 per kg) in Japan, and a recent DNA survey of whale meat for sale in Japan showed that 9 out of 16 samples, more than 50 percent, came from endangered whale species that are internationally protected. Certain native groups have engaged in subsistence hunting of whales for thousands of years. Subsistence hunting differs from commercial hunting in that the whales are consumed in the locale where they are caught, rather than sold. Many Eskimo, or Inuit, communities in the United States depend on whaling for economic, social, and cultural survival. The IWC allows some exceptions to the whaling ban for subsistence purposes. While it has been controversial at times, Inuit subsistence whaling is not considered to be a major threat to whale populations. After the eastern Pacific gray whale was removed from the endangered species list in 1995, the Makah tribe of Washington State began preparations to resume subsistence hunting of this species which formerly was one of their most important resources. The five or six whales the Makah propose to take each year are not likely to threaten the continued recovery of gray whales. Pollution Pollution poses a threat to whales around the world. Chemical contaminants in the water and in whales’ food sources may accumulate in their systems, and because they are long-lived, may reduce longevity and reproduction. Beluga whales are a kind of toothed whale, whales with teeth rather than baleen that may be endangered in part because of chemical pollution. Although they are protected from hunting, toxins such as DDT and PCBs contaminate the food they eat accumulate in their fatty tissues and cause a high rate of cancer in adult belugas.
Oil is another kind of chemical pollution that can harm whales. Twenty-nine gray whales were reported stranded in Alaska near the area of the Exxon-Valdez oil spill in 1989. Whales may ingest contaminated prey and sediments, or contact with oil may impair the filtering efficiency of their baleen. Another important concern is that air pollution has depleted the ozone layer above the Antarctic. Reduced ozone levels allow more harmful ultraviolet radiation (UVR) to reach the southern seas, and increased UVR may harm the phytoplankton and krill (tiny crustaceans) that the whales depend on for food. Exposure to UVR also may be responsible for skin lesions observed on whales in the area. Shipping Shipping poses a threat to some whale species. The North Atlantic right whale is highly endangered, and collisions with ships in the southeastern United States are killing one or two whales per year. Although this loss may not seem like much, it is having an effect because the species has only about 300 individuals left and produces only 10 calves each year, several of which die of other causes. Fortunately, the National Marine Fisheries Service (NMFS), the United States government agency responsible for helping whales recover from endangerment, may have found a way to help prevent these deaths. Spotter planes are flown over key areas where the whales gather, and the pilots radio ships to warn captains to steer clear of the whales. Boat traffic from well-meaning whale-watchers also may pose a threat to some species. Regulation of whale-watching boats to keep them a safe distance from whales is necessary to ensure that these vessels do not disturb the animals they wish to observe. Responsible whale-watching can help educate people about these wonderful animals and should be encouraged. Commercial Fishing Commercial fishing can have a negative impact on whales in two ways. Overfishing has heavily depleted many fish stocks around the world and removing food sources can harm the whales that depend on those fish. Whales also can become entangled in fishing nets, and because they are air-breathing mammals, entanglement frequently leads to drowning. Coastal Development Coastal development can pose a threat to whales that depend on near-shore habitat. Offshore drilling for oil and gas can cause increased noise disturbance, pollution, and threats from shipping. Dredging and vessel traffic associated with a salt extraction plant in one of the Mexican lagoons used by gray whales for breeding caused the whales to abandon that area in the 1960s. When the plant was closed the whales returned. Another salt operation in a different lagoon appears to have been tolerated by the whales, perhaps due to the dynamics of shipping in that lagoon. The Mexican government is considering proposals for more salt development in the area. Conservationists and the National Marine Fisheries Service (NMFS) disagree on the effects of the proposed developments. Conservation groups believe that the new salt operations may be a threat to gray whales, while the NMFS does not think the impact will be significant. Conservation Actions Whaling Moratorium The moratorium on commercial whaling approved by the IWC in 1982 went into full effect in 1986, and is just beginning to have an effect on whales, most of which reproduce very slowly. International protection has not helped most whales as much as it has helped the gray whale. The blue whale, largest of the whales at an average of 89 feet (27 m) long, was protected by the IWC in the mid 1960’s. Since then the population has continued to decline, however, and there are only about 1,000 blues whales left. Protected right whales also have declined from 300,000 to 3,000, while humpback whale populations have fallen from 120,000 to 10,000. Illegal hunting is a major problem. Protected Areas A recent development and cause for hope is the newly created whale sanctuary in the Antarctic. In 1994, the IWC created an 11-million square mile protected area in prime feeding habitat of the Antarctic that is used by many baleen whales. Enforcement of the whaling ban in this area remains a problem, and continued efforts are necessary to make the sanctuary effective. Directing Vessel Traffic Programs to help minimize conflicts and collisions between whales and ships, such as the spotter planes described earlier, are helping to protect whales. Another project is attempting to plot whale migration routes, so ships can be directed to avoid areas where whales frequently travel. Tourism Responsible tourism is helping to create a constituency of whale lovers who are helping to fund whale conservation efforts. Adopt-a-whale programs, where people donate money and receive reports on the well-being of a selected individual whale that is tracked in the wild, year after year, are helping to fund scientific research that increases our understanding of whales. Whale-watching trips are becoming increasingly popular and as the industry grows, the power and incentive to preserve whale’s increases. It is important that the whale-watching boats do not disturb the whales. In Mexico only a limited number of boats are permitted in the gray whales’ breeding and calving lagoons. To obtain a permit, boat captains must agree to follow rules that protect the whales. In the United States laws like the Marine Mammal Protection Act and the Endangered Species Act prohibit harassment of or harm to whales. Regulation helps protect coastal whales such as the gray, but most whales live in the open ocean and are outside the jurisdiction of any one country. These whales can recover only if many nations cooperate to help protect them. Analysis Questions: Answer the following questions on your own paper. Although gray whales are a coastal species, most other whales are primarily open-ocean dwellers. What is the best way to protect species, such as the blue whale, that roam the seas in waters outside the jurisdiction of any one country? Indigenous people who have traditionally hunted whales for thousands of years had little or no part in the massive commercial slaughter that has brought so many whale species to the brink of extinction. They received no benefits from the slaughter that now threatens the whales they depend on for subsistence. Whaling can be critical to the economic and cultural survival of some native groups. What is the best way to approach the inequity of this situation when regulating whaling? Small coastal villages in some countries such as Norway have participated in commercial whaling for several generations and may be dependent on revenue from whaling for survival. Should the international community try to persuade these villages to participate in the ban on commercial whaling? Or should they be treated the same way as native peoples who whale for subsistence purposes? 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