 |
|
Nile Delta fishery grows dramatically thanks to run-off of sewage, fertilizers
January 20, 2009Considered pollutants in the West, discharges help to feed millions in Egypt
NARRAGANSETT, R.I. - While many of the world's fisheries are in serious decline, the coastal Mediterranean fishery off the Nile Delta has expanded dramatically since the 1980s.
The surprising cause of this expansion, which followed a collapse of the fishery after completion of the Aswan High Dam in 1965, is run-off of fertilizers and sewage discharges in the region, according to a researcher at the University of Rhode Island Graduate School of Oceanography.
Autumn Oczkowski, a URI doctoral student, used stable isotopes of nitrogen to demonstrate that 60 to 100 percent of the current fishery production is supported by nutrients from fertilizer and sewage. Her research will be reported in the Jan. 21 online edition of the Proceedings of the National Academy of Sciences.
"This is really a story about how people unintentionally impact ecosystems," Oczkowski said.
Historically, the Nile would flood the delta every fall, irrigate nearby agricultural land, and flow out to the Mediterranean, carrying with it nutrients to support a large and productive fishery. Construction of the dam stopped the flooding, and the fishery collapsed.
"That's when fertilizer consumption in the country skyrocketed," said Oczkowski. "The Egyptians were fertilizing the land, and then fertilizing the sea with the run-off. It also corresponded with a population boom and the expansion of the public water and sewer systems."
As a result, landings of fish in coastal and offshore waters are more than three times pre-dam levels. While increased fishing effort in recent years may have played some role in the recovery, Oczkowski's findings indicate that anthropogenic nutrient sources have now more than replaced the fertility carried by the historical flooding.
Oczkowski and colleagues from URI, the U.S. Environmental Protection Agency, and the University of Alexandria collected more than 600 fish in 2006 and 2007 from four regions that received run-off from the delta and two areas not affected by the Nile drainage. Stable isotopes of nitrogen in each fish were measured and compared.
She found that the isotope signatures in the fish reflected two distinct sources of nitrogen: anthropogenic nitrogen from fertilizers and sewage in the fish caught in coastal and offshore areas of the delta, and nitrogen values consistent with the middle of the Mediterranean in fish caught in waters that were not affected by the delta drainage.
These results have raised questions among many scientists about the value of anthropogenic sources of nutrients to ecosystems.
"We're programmed in the West to think of nutrient enrichment of coastal systems as bad," Oczkowski said. "Here in Rhode Island we've spent hundreds of millions of dollars to upgrade sewage plants to reduce nutrient loading into Narragansett Bay. And it's a major issue in the Chesapeake Bay and in the Gulf of Mexico, where run-off of fertilizers from the country's breadbasket into the Mississippi River has caused a dead zone in the Gulf.
"But the Egyptians don't think it's a bad thing. For them, it's producing tons of fish and feeding millions of hungry people. It's forcing us to reconsider whether we can say that nutrient inputs are always a bad thing."
University of Rhode Island
Autumn Oczkowski, a URI doctoral student, used stable isotopes of nitrogen to demonstrate that 60 to 100 percent of the current fishery production is supported by nutrients from fertilizer and sewage. Her research will be reported in the Jan. 21 online edition of the Proceedings of the National Academy of Sciences.
"This is really a story about how people unintentionally impact ecosystems," Oczkowski said.
Historically, the Nile would flood the delta every fall, irrigate nearby agricultural land, and flow out to the Mediterranean, carrying with it nutrients to support a large and productive fishery. Construction of the dam stopped the flooding, and the fishery collapsed.
"That's when fertilizer consumption in the country skyrocketed," said Oczkowski. "The Egyptians were fertilizing the land, and then fertilizing the sea with the run-off. It also corresponded with a population boom and the expansion of the public water and sewer systems."
As a result, landings of fish in coastal and offshore waters are more than three times pre-dam levels. While increased fishing effort in recent years may have played some role in the recovery, Oczkowski's findings indicate that anthropogenic nutrient sources have now more than replaced the fertility carried by the historical flooding.
Oczkowski and colleagues from URI, the U.S. Environmental Protection Agency, and the University of Alexandria collected more than 600 fish in 2006 and 2007 from four regions that received run-off from the delta and two areas not affected by the Nile drainage. Stable isotopes of nitrogen in each fish were measured and compared.
She found that the isotope signatures in the fish reflected two distinct sources of nitrogen: anthropogenic nitrogen from fertilizers and sewage in the fish caught in coastal and offshore areas of the delta, and nitrogen values consistent with the middle of the Mediterranean in fish caught in waters that were not affected by the delta drainage.
These results have raised questions among many scientists about the value of anthropogenic sources of nutrients to ecosystems.
"We're programmed in the West to think of nutrient enrichment of coastal systems as bad," Oczkowski said. "Here in Rhode Island we've spent hundreds of millions of dollars to upgrade sewage plants to reduce nutrient loading into Narragansett Bay. And it's a major issue in the Chesapeake Bay and in the Gulf of Mexico, where run-off of fertilizers from the country's breadbasket into the Mississippi River has caused a dead zone in the Gulf.
"But the Egyptians don't think it's a bad thing. For them, it's producing tons of fish and feeding millions of hungry people. It's forcing us to reconsider whether we can say that nutrient inputs are always a bad thing."
University of Rhode Island
Fisheries Current Events and Fisheries News RSSScientists Unravel Evolution of Highly Toxic Box Jellyfish
With thousands of stinging cells that can emit deadly venom from tentacles that can reach ten feet in length, the 50 or so species of box jellyfish have long been of interest to scientists and to the public. Yet little has been known about the evolution of this early branch in the animal tree of life.
TEEB report released on the economics of ecosystems and biodiversity for policy makers
Policy makers who factor the planet's multi-trillion dollar ecosystem services into their national and international investment strategies are likely to see far higher rates of return and stronger economic growth in the 21st century.
Studies show marine reserves can be an effective tool for managing fisheries
Studies conducted in California and elsewhere provide support for the use of marine reserves as a tool for managing fisheries and protecting marine habitats, according to biologists at the University of California, Santa Cruz.
Coral reefs inspire rare consensus -- just save them
One of the first set of studies to examine what tourists and recreation enthusiasts actually think about coral reef ecosystems suggests they are a rare exception to controversies over human use versus environmental conservation - their stunning beauty is so extraordinary that almost everyone wants them protected in perpetuity.
North Atlantic Fish Populations Shifting as Ocean Temperatures Warm
About half of 36 fish stocks in the Northwest Atlantic Ocean, many of them commercially valuable species, have been shifting northward over the last four decades, with some stocks nearly disappearing from U.S. waters as they move farther offshore, according to a new study by NOAA researchers.
Remotely Operated Vehicles and Satellite Tags Aid Turtle Studies
Researchers are using a remotely operated vehicle (ROV) and satellite-linked data loggers to learn more about turtle behavior in commercial fishing areas and to develop new ways to avoid catching turtles in fishing gear.
World interest in Australian fishery impact test
An Australian method for assessing the environmental impact of marine fisheries has caught the eye of fishery management agencies worldwide.
National Science Foundation awards grants for studies of coupled natural and human systems
How do humans and their environment interact, and how can we use knowledge of these links to adapt to a planet undergoing radical climate and other environmental changes?
World will miss 2010 target to stem biodiversity loss, experts say
The world will miss its agreed target to stem biodiversity loss by next year, according to experts convening in Cape Town for a landmark conference devoted to biodiversity science.
Tropical regions to be hardest hit by fisheries shifts caused by climate change: UBC research
Major shifts in fisheries distribution due to climate change will affect food security in tropical regions most adversely, according to a study led by the Sea Around Us Project at The University of British Columbia.
More Fisheries Current Events and Fisheries News Articles
 |
Fisheries Biology, Assessment and Management by Michael King (Author) This excellent second edition of Fisheries Biology, Assessment and Management, has been fully updated and expanded, providing a book which is an essential purchase for students and scientists studying, working or researching in fisheries and aquatic sciences. In the same way that excessive hunting on land has threatened terrestrial species, excessive fishing in the sea has reduced stocks of marine species to dangerously low levels. In addition, the ecosystems that support coastal marine species are threatened by habitat destruction, development and pollution. Open access policies and subsidised fishing are placing seafood in danger of becoming a scarce and very expensive commodity for which there is an insatiable demand. Positive trends include actions being... |
 |
Fisheries Ecology and Management by Carl J. Walters (Author), Steven J. D. Martell (Author) Quantitative modeling methods have become a central tool in the management of harvested fish populations. This book examines how these modeling methods work, why they sometimes fail, and how they might be improved by incorporating larger ecological interactions. Fisheries Ecology and Management provides a broad introduction to the concepts and quantitative models needed to successfully manage fisheries. Walters and Martell develop models that account for key ecological dynamics such as trophic interactions, food webs, multi-species dynamics, risk-avoidance behavior, habitat selection and density-dependence. They treat fisheries policy development as a two-stage process, first identifying strategies for varying harvest in relation to changes in abundance, then finding ways to implement... |
 |
Virginia Wildlife by Virginia Dept of Game and Inland Fisheries For 63 years, Virginia Wildlife magazine has been dedicated to bringing its readers the best in hunting, fishing, boating, and wildlife resource information from around the state. Its award winning design, feature articles, spectacular color photography, and original artwork is an excellent way to explore Virginia's great outdoors. |
 |
Dept 56 North Eastern Sea Fisheries LTD by Department 56 North Eastern Sea Fisheries Ltd. Size: 8 x 7 x 7.5" |
 |
Great American Puzzle Factory Impossible Puzzle Fishery by Great American Puzzle Factory Impossible Puzzles feature the artwork of Alex Beard; the painter, writer and traveler. The uniquely shaped pieces allow you to create free form puzzle designs of your own or assemble the puzzle as depicted on the box. The box folds to create an easel to enable you to easily view the box top while assembling. What will you create with your Alex Beard Impossible Puzzle? Country of Origin is U.S.A. and China. |
 |
Marine Fisheries Ecology by Simon Jennings (Author), Michel Kaiser (Author), John D. Reynolds (Author) CLICK HERE TO DOWNLOAD ARTWORK This topical and exciting textbook describes fisheries exploitation, biology, conservation and management, and reflects many recent and important changes in fisheries science. These include growing concerns about the environmental impacts of fisheries, the role of ecological interactions in determining population dynamics, and the incorporation of uncertainty and precautionary principles into management advice. The book draws upon examples from tropical, temperate and polar environments, and provides readers with a broad understanding of the biological, economic and social aspects of fisheries ecology and the interplay between them. As well as covering 'classical' fisheries science, the book focuses on contemporary issues such as industrial fishing,... |
 |
T-Shirt Womens Black " The person wearing this T-SShirt is a Boating And Fisheries Patrol Officer " Occupations Large by TopExpressions |
 |
SEAGATE Pediatric Earache Remedy, .5-Ounce Boxes (Pack of 2) by SEAGATE Pediatric Earache Remedy ( ear drops ) .5 oz For the temporary relief of earaches, otitis media, inflammation of external and internal ear and eustacian tubes. All natural with no chemicals. A homeopathic combination with Olive Leaf Extract to heal the body in two ways. Homeopathic ingredients stimulate your body so that your body heals itself by dealing with the source of your symptoms. Olive Leaf Extract is known for its antimicrobial properties. Seagate Earache Remedy should be kept in every medicine cabinet in advance of the cold and flu season. Seagate manufactures raw materials from their own organic fishing and farming operations. For more information call 24 hrs/day toll free 1-888-505-GATE or visit www.seagateproducts.com |
 |
The Greenland Whale Fisheries Judy Collins & Theodore Bikel (Primary Contributor) |
|
Arizona Fisheries #2: Salt River Lakes, The Incredible Carp, Lee's Ferry, Alamo Lake, Arizona Everglades Also With: various (Primary Contributor) |
| © 2009 BrightSurf.com |