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Discussion Starter · #1 ·
Ancient fishing linked to modern crisis

Report: Ancient fishing linked to modern crisis

By Richard Stenger CNN

(CNN) -- Ecological upheavals in coastal waters began thousands of years ago as primitive peoples massacred the denizens of the sea, leaving marine environments susceptible to the escalating pressures of contemporary times, according to a new report.

Examining ancient garbage mounds, sediment deposits and archeological records from four continents, scientists found that excessive hunting of sea mammals, turtles and fish upset delicate webs of life on a scale never before realized.

The disruptions unleashed population explosions of opportunist species and lethal epidemics against less fortunate ones, and contributed to the conditions that strain oceans in modern times, the scientist team reported in a study to appear Friday in the journal Science.

"What we're finding is a number of the crises that our marine ecosystems are facing today can be traced back thousands of years in some cases, and hundreds of years in others, to when human beings first began affecting those ecosystems," said co-author Karen Bjorndal.

Fishy garbage from the past

In America, while overfishing reached its peak in the Colonial and modern eras, it became a problem long before the arrival of Europeans, "contrary to romantic notions of the supposedly superior ecological wisdom of non-Western and pre-Colonial societies," the paper stated.

In contrast to the narrow geographic and chronological focus of many studies, the report draws on the research of dozens of coastal ecosystems from North America, Europe, Asia and Australia.

The scientists reconstructed fishing patterns over time through a variety of means. They read historic accounts, including one from the Chesapeake Bay describing a long cannon "clearly visible in over 30 feet of water." They sifted through refuse mounds in the Caribbean and Maine, chock full of fish leftovers thrown away thousands of years ago.

Alligators in the Chesapeake

The over-harvesting was akin to Stone Age hunting, which drove dozens of beasts to extinction, with two major exceptions, the time detectives concluded.

"On the land, as we killed off the giant mammals and destroyed the ancient forests, we replaced with a new suite of farmed species. In the coastal seas, we took out animals and replaced them with nothing," said co-author Roger Bradbury of Australia.

Colonial-era sea hunters placed added pressures on North Atlantic coastal waters
The disappearance of predators and other key links in the food chain set off a succession of events that have indirectly lead to ecological instability in our age, such as toxic algae blooms, dead zones and outbreaks of disease, according to the report.

In the Chesapeake Bay, vast reefs of oysters once flourished, acting as natural filters in an estuary that harbored alligators, Grey whales, giant sturgeon and hammerhead sharks.

But with Native and Colonial Americans picking the reefs clean, nothing prevented choking waves of algae from turning the bay into a murky and biologically impoverished mess, the scientists said.

Glimmer of hope in the water

In the Caribbean, dwindling numbers of grazing green sea turtles no longer keep turtle grass in check, making the underwater forests vulnerable to periodic plagues, which in turn threaten a host of species dependent on the plant.

Land and sea hunting differed in another crucial way, which could be the key to the restoration of damaged water ecosystems. Only a handful of coastal species, like the Steller's Sea Cow in the North Pacific and the Caribbean monk seal, were driven to complete extinction as result of human harvesting.

While depleted, populations of species such as green sea turtles, sea otters and others have managed to cling to survival with enough numbers to allow their revival, the scientists said.

Pollution and high-tech fishing techniques have escalated the pressures on the deep. But marine conservation practices that take into account the long-term biographies of coastal ecosystems could help restore them.

"We need to change the way we think about our coastal seas; not pristine, but damaged, and equally not hopeless, but salvageable. Our research points the way," Bradbury said.

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Just like to make a point.......we as humans are not just outside observers.....we are part of the ecosystem too!

Catastophically, we can destroy it - and ideally, we can restore it to what it once was. Realistically, we have to settle for middle ground.

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JMHO, but is smells fishy...

the giant mammals disappeared due to a receding ice age and couldn't compete in a warmer climate; the last of the large land mammals were the wooly mammoth and mastadon. all others were extinct by prehistoric times. i doubt that early man had enough technological sophistication or numbers to effect extinction of an entire species. sounds like more anti-human propaganda from PETA.

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Discussion Starter · #4 ·
Peta - Phobe ?


i am not sure where you find the evil hands of peta in the article.

the last ice age occured around 18,000 years ago, the focus of this study was:

"What we're finding is a number of the crises that our marine ecosystems are facing today can be traced back

thousands of years in some cases, and hundreds of years in others,

to when human beings first began affecting those ecosystems,"

i had posted the above CNN reporting of the study because it was a much shorter version that what appeared in NATIONAL GEOGRAPHIC and its first appearance was in SCIENCE magazine.
i am sure you are aware of those respected magazines and institution, i doubt they are the bastion of peta malcontents.
i will post the national geographic version which gives more detail into the study.

personally i find it quite interesting and i think it relates very well to the current problems in the ocean due to the lack of large sharks in the enviornment.

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Discussion Starter · #5 ·
Overfishing Long Ago Tied to Modern Ecosystem Collapse,Overfishing Long Ago Tied to Modern Ecosystem Collapse

Hillary Mayell
for National Geographic News
August 7, 2001

Overfishing that took place hundreds if not thousands of years ago is a key culprit in the collapse of coastal marine ecosystems today, an international group of researchers reports.

Up until now, scientists have tied the current collapse of the world's coastal ecosystems almost entirely to recent human impacts-pollution, increased nutrient runoff, and climate change. By looking at historical evidence, the researchers were able to draw a picture of ancient oceans teeming with life in an abundance heretofore unimagined.

The picture today is dramatically different: dying coral reefs, dwindling populations of marine mammals, fish, and shellfish, shrinking seagrass beds, increased invasions of alien species, noxious algal blooms, and more virulent and frequent outbreaks of disease.

This current state of affairs can be attributed at least in part to the actions of aboriginal coastal populations, say the authors of the two-year study, which was published August 3 in Science.

"Up until now weve been attributing the collapse of coral reef ecosystems to pollution and global warming," said co-author Karen Bjorndal, a marine ecologist at the University of Florida's Archie Carr Center for Sea Turtle Research. "While that's certainly a factor and something society must address, ecosystem collapse was set in motion long before modern activities contributed."

The authors hope their work will help reorient current conservation and restoration practices away from quota systems and no-fishing zones to a more broad-based ecosystem approach.

"We need to change the way we think about our coastal seas-not pristine, but damaged, and equally not hopeless, but salvageable," said co-author Roger Bradbury of the Australian National University in Canberra.

Long-Term Domino Effect

In their report, the authors note that large marine vertebrates-whales, manatees, dugongs, sea cows, monk seals, crocodiles, codfish, jewfish, swordfish, sea turtles, sharks, and rays-are now functionally or entirely extinct in most coastal marine ecosystems.

They found that the depletion of these species through overfishing and overharvesting sets off a domino effect that can have impacts even centuries later.

To draw a picture of what marine ecosystems looked like eons ago, the 19 researchers who contributed to the study examined marine sediment evidence from about 125,000 years ago, archaeological information from early human coastal settlements some 10,000 years ago, and European trade records from the 15th century to the present.

In every case they looked at, overfishing by humans preceded ecosystem collapse.

Removing important marine species has a profound effect on the food chain, which ultimately leads to ecosystem breakdown, the authors say. The impacts of historic depopulation of sea turtles is one example.

"The accepted wisdom among sea turtle researchers has always been that sea turtle stocks were in pretty good shape when Columbus arrived, and that it wasn't until the Europeans started to arrive that the populations began to crash," Bjorndal explained.

When the scientists examined archaeological evidence of coastal Amerindian settlements, they found that sea turtles were an important food source for the people who lived there. Over the 100 to 200 years that followed, the amount of turtle remains found in ancient trash dumps diminished until there were no more traces of sea turtles as a food source.

The findings challenge a common assumption held by marine biologists that the consumption or use of a species by indigenous groups generally has a negligible or strictly localized impact.

"We had always thought that the impact of subsistence-level fishing would be limited to a local area," said Bjorndal. "But sea turtles travel long distances to forage for food and then return to their nesting site. By overharvesting the species at a local level, the Amerindians had a region-wide impact on the ecosystem."

Now, several hundred years later, the depletion of sea turtle populations is having a profound effect on the health of coral reefs in the Caribbean, Bjorndal said.

Sea turtles were one of many species that controlled the growth of algae. Other algae-eating species were also slowly eliminated over time, until only the sea urchin remained. In the 1980s, sea urchin populations plummeted following a well-documented outbreak of disease.

With no plant-grazing species left, the reefs were swamped by an overgrowth of algae, which killed many corals and prevented new ones from growing.

Common Pattern

The researchers found the same pattern in all the other cases they studied.

Co-author Jim Estes, a research ecologist with the Western Ecological Research Center in Santa Cruz, California, described the chain of events that occurred in the North Pacific after aboriginal Aleuts greatly reduced sea otter populations starting about 2,500 years ago.

Sea otters are the major predators of sea urchins. As their major predators were removed from the ecosystem, sea urchin populations soared.

Overgrazing by the sea urchins eventually killed off the kelp beds, resulting in changes in wave action, water quality, and siltation rates. These changes, in turn, had a major impact on other near-shore flora and fauna.

In another instance, the Chesapeake Bay now has vast areas in which algae is so abundant that the level of oxygen in the water is inadequate to support other organisms. The authors tie this process, known as eutrophication, in part to the collapse of oyster populations caused by overfishing in the 19th century.

Management Implications

"Our study shows that marine ecosystem collapse is not entirely due to recent factors, and that to really understand what's happening we need to view the problem in its proper historical perspective," said Bjorndal.

Estes said the emphasis on recent human activities as the cause of ecosystem collapse may have arisen in part because ecological data on coastal marine systems has only been collected and studied since the 1950s. As a result, researchers' insight is limited mainly to the recent structure and function of ecosystems.

The new report points to the need to manage marine ecosystems for long-term effects and not just immediate problems.

"For ecosystem restoration and management to be effective, we need to go back far enough in time to truly identify the problems and set our goals appropriately," said Bjorndal.

The study also highlights the importance of maintaining the biodiversity of an ecosystem, she added.

"It's not enough to bring back one species," said Bjorndal.

"In a healthy marine ecosystem, there are a suite of animals that fill the same ecological niche," she said. "The loss of redundancy-where numerous species fill the same environmental niche-leaves an ecosystem extremely vulnerable."

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megalodon, i read a newspaper account of this article a while back and also found it interesting. thank you for sharing it with us.

is the "national geographic" story exactly the same as the article that appeared in "science"?

is that last quoted paragraph by Karen Bjorndal also contained in the "science" article and accurately reproduced here?

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I think we all can agree that the human species has had a profound effect on this earth. Cod were so thick in Georges Bank when the settlers arrived that a basket could be lowered into the water and would come up full. We fished for them, salted them on the rocks in Newfoundland and sent them down to the Carribean to feed slaves working in the sugar plantations, and brought back rum. Then they became commercially extinct... Giant Sturgeon killed people crossing the Hudson. Are they common now? Horseshoe crabs were ground up as fertilizer, etc. Now their blood is utilized in the prescription drug industry. The skies over the Great South Bay used to be dark with black ducks in the 1950s...Have you caught blowfish in any numbers on the south shore lately? Moriches used to be famous for flounder fishing, now we just pass the time until the fluke arrive. I think things are slowly getting better and we have discovered as a race that we are not alone on this earth. Unfortunately we will not undo the damage in our lifetimes.

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Gators in the Chesapeake ? Hmmmmmm...seems we might have read about that before.... I am sure there were giant reptiles there at one time, but not so sure about Colonial era.

Interesting article anyway, and it's sad to see things going downhill, but maybe it's not too late.

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Discussion Starter · #10 ·

the science magazine is only available online if you are a member.
i am not a member and cannot access it to post here.

if you want to persue it further:
Science 2001 July 27

striper77- there are many things hard to imagine exsisted in our local waters in the not so distant pass. but it is difficult to argue with fossils and carbon-14 dating as proof.

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thanks anyway, megalodon

i am not online with "science", but i do have inconvenient access to a few marine science libraries where i can check it out.

i doubt she made that statement in the journal "science". probably a misquote on the part of the author of the "national geographic" piece. that kind of thing happens far too often when journalists that have insufficient scientific training attempt to describe scientific articles for the popular press.

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FREE online access to the journal

hey thanks megalodon, i went to the link and found out that you can register for free access to "science". they have various levels of use and cost.for free - you can search and view the table of contents, titles and abstracts of all the articles. you are supposed to be able to access the full text of all articles over 1 year old. this should include the article we have been talking about, "Historical Overfishing and the Recent Collapse of Coastal Ecosystems", unfortunately the articles are grouped quarterly. thus we will have to wait until oct 1 to access (at no charge) the full text of this article from the 3rd quarter 2001.

anyway, i did print out the abstract (a concise summary). i don't want to post the abstract as that might be a violation of copyright laws, so if anyone else is interested in this just follow the link that megalodon has provided.

once again, megalodon, thanks.

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>>>The over-harvesting was akin to Stone Age hunting, which drove dozens of beasts to extinction, with two major exceptions, the time detectives concluded

On the land, as we killed off the giant mammals and destroyed the ancient forests, we replaced with a new suite of farmed species. In the coastal seas, we took out animals and replaced them with nothing," said co-author Roger Bradbury of Australia. <<<

Most of the giant mammals (e.g. the sabre toothed tiger, all giant marsupials, etc.) died off millions of years before man appeared. Unless by "giant mammals" Mr. Bradbury is referring to the American Bison, Bears, etc.

Very confusing. I still don't beleive that even a few million native americans (a large figure for coastal areas) could effect such an impact. Remember that they even lacked the mechanical innovations like lever, pulley and wheel. Linked? Well, kinda like "6 degrees of Separation", you can just about link everything; doesn't mean that it's true.

I accused PETA because they've generally encouraged a mindset that humans are a cancer on the planet. By implacating man going back thousands of years, they could be setting the stage for attacking the legal rights for hunting and fishing by native american tribes. And if THEY have no right to fish/hunt, then what rights do we have (I'm assuming that none of you are native americans)?

True, early man probably had some impact on the environment, but only a TINY fraction of what we've done over the last 200 years. Remember that there are currently more people alive right now than have ever existed on the planet.
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