Biodiversity and
Conservation: A Hypertext Book by Peter J. Bryant
Chapter 5:
EXTINCTION AND DEPLETION FROM OVER-EXPLOITATION
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HISTORICAL
EXTINCTION EVENTS THE FUR TRADE |
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Registered UCI students: view the slide show for this chapter or download it: http://darwin.bio.uci.edu:80/~sustain/protected/chap5slides.ppt |
HISTORICAL EXTINCTION EVENTS
Some survivors from the Pleistocene have been driven to extinction during historical times by over-exploitation:
Aurochs
A European member of the cattle family, the Aurochs, was a
long-horned, forest-dwelling ancestor of modern domestic cattle. It was hunted
for sport and food, and suffered from habitat loss. Its last holdout was
in a private game reserve in
Sea Cow
This was a heavy, slow-swimming marine mammal related to the
manatee and dugong (Sirenians),
but much larger (25-30 feet long). It was discovered in 1741 in the ocean
around the Pribilof Islands in
Surviving relatives
The closest surviving relative of the sea cow, the much smaller
dugong, is in serious trouble. Dugongs are
found in a huge area from the
Another small relative of the sea cow that is endangered by
human activities is the Manatee (West Indian or Florida
Manatee), a slow-swimming, friendly marine mammal that feeds on sea grass and
lives in the coastal waterways of Florida and in other coastal areas around the
Caribbean. There are about
2,000 animals in the population, but at least 200 die each year, mainly
from collisions with speedboats.
Manatee deaths in Florida |
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Year |
Manatee deaths |
From boat injuries |
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1996 |
415
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60 |
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1997 |
242 |
54 |
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1998 |
231 |
66 |
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1999 |
268 |
81 |
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2000 |
272 |
78 |
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2001 |
325 |
81 |
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2002 |
305 |
95 |
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2003 |
380 |
73 |
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2004 |
264 |
69 |
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2005 |
396 |
80 |
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2006 |
416 |
86 |
Despite the manatee's precarious situation, a consortium of
Great Auk
The Great Auk was a 3-foot tall penguin-like flightless seabird. It was a very fast underwater swimmer, but clumsy on land. Hundreds of thousands of these birds lived in the North Atlantic. They were hunted between 1785 and 1844, mainly for their feathers which were used for mattress and pillow stuffing. The last breeding pair was killed by two fishermen, who also smashed the last egg.
Carolina Parakeet
The Carolina Parakeet was the only endemic parrot of North America. Unfortunately, these birds fed in large flocks on fruit and other crops, and were shot in huge numbers by farmers. They were also collected for their feathers and for sale to zoos. The last pair survived in the Cincinnati zoo until 1917-18.
Passenger Pigeon
The passenger pigeon was an attractive bird with a blue back and a pink breast that existed in huge populations. In fact, it may have been the most abundant bird ever to have lived. John James Audubon observed a flock of pigeons passing over a period of three days at a rate he estimated at over 300 million birds an hour. The passage of large flocks created a roar of wings that could be heard 6 miles away. The pigeons nested in long narrow colonies that could be 40 miles long and several miles across. They occurred throughout Eastern North America where they fed on acorns and beechnuts.
Early settlers in the United States developed a taste for passenger pigeon and commercial hunters devised many different ways of killing large numbers of the birds. They were suffocated by burning grass or sulphur below their roosts; fed grain soaked in alcohol; beaten down with long sticks, blasted with shotguns, caught in nets or trapped using a decoy pigeon.
By the 1880's the huge flocks were gone from the coastal states
and were dwindling everywhere else. The last wild passenger pigeon was seen in
THE FUR TRADE
The hunting of animals for their hides (for leather) or fur played a very important part in the exploration and history of Europe, Asia and North America. It also led to a drastic reduction in the abundance of (though fortunately not the extinction of) many kinds of fur-bearing animals.
The Russian Fur Trade
The Fur Trade began in earnest in medieval times in Europe, when it involved the hunting of European animals to stock the wardrobes of the nobility and royalty. It involved mainly small animals such as squirrels, martens, ermine (=white phase of weasel), sable and foxes, and they were usually trapped alive so that their furs could be collected undamaged. Several hundred squirrel pelts were needed to make one cloak, so the numbers killed were enormous. Eventually, by the early 16th century, the populations of fur-bearing animals in Western Europe were almost exhausted, and this led to the exploration of the northern forests of Russia and the development of an international trading system. This trade was a major driving force behind the Russian expansion into Siberia, and the fur trade became Russia's economic foundation. It is estimated that, at the height of the squirrel trade (14th-16th centuries), Novgorod (one of three main centers) was exporting half a million squirrel skins a year. The fur-bearing animals of the vast Siberian forests were virtually eliminated by the end of the 18th century. In the 1920's the American mink was introduced into Europe because of its superior fur compared to the native European species. Now, at least in part because of this introduction, the European mink is the continent's most endangered mammal. An "Island retreat" has been established in the Baltic Sea to try to rescue this species from extinction.
Sea Otters
When the Russian traders had exhausted the terrestrial fur-bearing animals they turned their attention to the sea otters that were discovered in 1741 in the north Pacific, on the Russian and Alaskan coasts. At that time, there were between 150,000 and 300,000 otters living along the north American coast from Alaska to Baja California. From 1750 to 1790 most of the animals were killed by hunters, then they were too scarce to be worth hunting (they had reached "commercial extinction") and the trade collapsed. By 1911, when the otters received some protection through the International Fur Seal Treaty, there were only 1-2,000 animals left throughout their range. The population recovered well and the Alaskan (Aleutian Island) population reached a peak in the mid-1970s of about 50,000-100,000 animals. But from 1992 to 2000 it declined by 95% and now as few as 6,000 otters may remain in the entire Aleutian chain. This is just one part of a catastrophic ecosystem collapse that is occurring in the area.
Another population of about 2,400 sea otters survives along the California coast between Point Conception and Monterey Bay. They are coming into increasing conflict with inshore fisheries for sea urchins.
The American Fur Trade
Partly because of the decline of the Russian fur bearing animals, from the earliest days of European settlement in North America, the fur trade has been one of the main incentives for westward expansion. For a long time, the colonists simply traded their goods for furs that the Native Americans collected. Later the Europeans became trappers as well as traders.
The strategy of the trappers in North America was similar to what had been responsible for depletion of these animals in Europe and Russia - they would exploit an area until the animals were so scarce that it was no longer profitable to hunt them, then they would move on to other areas and repeat the cycle.
One of the favorite targets of the trappers in North America was the beaver, the largest of the North American rodents. It was once extremely abundant throughout most of the continent but went into decline as early as 1638, mainly because the great insulating qualities of beaver fur made it the best material for hat manufacture. Beaver-fur hats were fashionable until the early nineteenth century, and the hunting pressure during this time virtually wiped out the species east of the Mississippi.
At the beginning of the 19th century, the fur trade in North America moved on to its last frontier, west of the Mississippi. In 1805 when the first explorers (Lewis and Clark) crossed the Rocky Mountains and continued on to the Pacific coast they reported that the area was "richer in beaver and otter than any other country on earth". The fur trappers were close behind the explorers, and in less than 40 years they had virtually cleared the area of both beaver and otter. By 1840 the beaver had been overexploited to the level where it was no longer worth hunting. The trappers had nowhere else to go, but they could switch to less desirable species. For a few years the trade was sustained by muskrat and marten furs, but these were also soon depleted.
Beavers have been protected in the 20th century and are now doing quite well on both sides of the Rocky Mountains. Now the beavers that still exist are often considered pests because they dam up creeks and cause flooding that leads to property damage. Oregon's beaver population causes about $250,000 in damage to roads, crops and businesses each year; the population is controlled mainly by professional trappers who catch about 5,000 beavers a year. In New York State bills have recently been introduced that would legalize underwater traps that kill beavers by drowning.
Not only beaver, but many other wildlife species in this country were almost eliminated by the fur trade. The Hudson's Bay Company was responsible for promoting the hunting of hundreds of thousands fur-bearing animals every year in North America, and exporting the hides and furs to Europe. The most valuable were the various members of the weasel family including the short-tailed weasel in its white or "ermine" phase, the otter, mink, pine marten, fisher, and wolverine. Of these animals, only weasels, otters and mink remain widespread, and the weasel is the only one that is still abundant. These animals were reduced initially by the fur trade, but most of them have also suffered from reduction in their forest habitat.
SEAL HUNTING
Fur seals. The loss of furs from other sources was a major incentive leading to massive hunts for various types of seal. The animals were usually clubbed to death when they came ashore to breed. The pattern was familiar - the discovery of large populations of target species, the development of intensive hunting leading to extermination or depletion, the move to a new area. The first phase (1780-1820) was directed at the southern fur seal in many areas of the southern hemisphere and was carried out by sealers from Europe, Russia, Canada and the U.S. Each of the following areas was the site of a fur seal hunt until the population was either commercially extinct (depleted to the level where it was not profitable to hunt) or really extinct:
Exhaustion of fur seal hunts in the Southern Hemisphere, 1780-1820 |
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1790-1791 |
Tristan da Cunha |
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1790-1791 |
Falkland Islands |
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1790-1791 |
Tierra del Fuego |
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1797-1803 |
Mas Afuera
(Juan Fernandez Islands) |
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1800-1825 |
South Georgia |
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South Shetland Islands |
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1800-1825 |
Kerguelen Island |
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Australian coast |
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1810-1820 |
Macquarie Island |
Off the west coast of Namibia in Africa, 40- 50,000 cape fur seal are taken each year. This is about 10% of the world's sealing activity, and much of the profit comes from the sale of penises for the aphrodisiac trade in Asia. Most of the seals are being killed by clubbing to death, which is claimed to be a humane method.
In the North Pacific,
the northern fur seal was hunted on the Pribilof Islands in the
Harp seal. A massive seal hunt also developed in the North Atlantic, taking advantage of the huge harp seal population that breeds on the pack ice in winter around Labrador and Newfoundland. The sealers, from Newfoundland, focused on the newborn seals with pure white fur, although adults were also taken for their oil as well as fur. The Newfoundland sealing industry began in the early 19th century and peaked at about 600,000 animals per year in the 1850's. This ultimately led to reduction in the size of the herd to about one fifth of its original size, and the industry went into decline in the early 20th century. A 1998 study shows that the current level of hunting (350,000 animals killed in one season) is not sustainable, and 12 members of Congress have written to Secretary of State Madeleine Albright declaring their opposition to this hunt. Again in 1999 Canada is being criticized for allowing 275,000 of these animals to be killed in spite of public opinion against it. The adult harp seals are also hunted on a subsistence level further north by Inuit hunters, who use the meat for food but also sell the skins in order to pay for the snowmobiles, rifles, gasoline and ammunition that are used in their hunting activities.
Another herd of harp seals, at Jan Mayen Island in the Arctic ocean, was wiped out by a rapid boom and bust between 1840 and 1860.
Elephant Seals were hunted in
the Pacific in the 1800s by whalers who wanted to supplement their catch. They
were hunted for their oil rather than their fur or skin. Hundreds of thousands
of these animals were killed in the southern ocean and along the coast of
California. The southern population (a distinct subspecies) was saved when the
Kerguelen and Macquarie Islands were turned into nature reserves, but in 1884
it appeared that the northern subspecies had been lost. However, a small colony
of about 50-100 had survived on Guadalupe Island off the coast of Baja
California. The species was given protection by the Mexican and U.S.
governments in the 1920s and the stock is now doing quite well. Today, there
are approximately 160,000 northern elephant seals! A large breeding
population (~2000) now congregates on the beach at Ano
Nuevo, fifty-five miles south of
Caribbean
monk seals, once abundant and native to the
Walruses were killed for
three centuries for their oil, skin, and ivory from their tusks. They were once
abundant in the North Pacific, North Atlantic and the Arctic Oceans, but like the
other seals, walruses were hunted almost to extinction. They are now protected
in this country and the walrus population appears stable at about 200,000
individuals.
Different Views |
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The most vociferous opposition to marine mammal
hunting has come from anti-cruelty activists and animal welfare organizations
including the International Fund for Animal
Welfare and the Sea Shepherd
Conservation Society. They argue that clubbing animals to death or
puncturing their skulls with an iron spike is inhumane. |
The North Atlantic Marine Mammal Commission is conducting scientific studies on the best way to kill marine mammals. |
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Another form of opposition to marine mammal
hunting has been based on the danger it poses to the survival of these
species. This viewpoint emphasizes that most hunts have not been
sustainable, but have seriously depleted or wiped out the target population
in a "boom and bust" cycle. |
The fact that many hunted populations have recovered quite well after we stopped hunting them leads to pressure to continue hunting and to try to manage the activity on a "sustainable" basis. The High North Alliance was established to defend the right of coastal communities to utilize marine mammals sustainably. You can post your opinions on their web site. |
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Walruses, seals and sea lions are protected in
the |
The Act, and a European import ban in 1983, has removed a major source of income for the Inuit. |
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Copyright ©2002 Peter J. Bryant
(pjbryant@uci.edu), |
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