Imagine the worlds oceans teeming with whales, sea turtles and fishes, with shellfish so abundant they posed a hazard to navigation. Only in a Jules Verne classic fantasy? Not so. A group of scientists from several research institutions has recently depicted that such rich ocean life existed in the not-so-distant past. Writing in the journal Science, the scientists have documented long-term effects of fishing and provided a framework for repairing coastal marine ecosystems that have collapsed from centuries of overfishing. The information comes none too soon for those who study and manage marine resources.
Successful management and restoration of coastal marine ecosystems has failed in part because of a lack of understanding the deeper historical causes of collapses in these ecosystems, said Dr. Jim Estes, a USGS research ecologist with the Western Ecological Research Center in Santa Cruz, Calif., one of the authors of the article.
The scientists examined paleoecological records from marine sediments dating from about 125,000 years ago; archaeological records from human coastal settlements occupied after about 10,000 years ago; historical records from documents of the first European trade-based colonial expansion in the Americas and South Pacific in the 15th century to the present; and ecological studies from the past century to help calibrate the other records.
They found that the three cultural stages they examined --aboriginal, colonial and global -- occurred at different and distinct times in the Americas, New Zealand and Australia. This enabled the scientists to distinguish fishing in these locations by cultural stages. The scientists also were able to determine whether changes occurred due to human impacts or changing climate. They compared the function and structure of kelp forests, coral reefs and estuaries before and after fishing occurred.
The scientists found that as human disturbance occurred over time, ecosystem structurePage: 1 2 3 Related biology news :1
Contact: Gloria Maender
United States Geological Survey
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