The Devastating Effects of Bottom Trawling

Video: The Devastating Effects of Bottom Trawling – Bottom trawling is laying waste to the precious ecosystems of the deep sea. Sigourney Weaver calls on delegates of the UN to take immediate action to stop this destruction.

Bottom Trawling Impacts On Ocean, Clearly Visible From Space

Bottom trawling, an industrial fishing method that drags large, heavy nets across the seafloor stirs up huge, billowing plumes of sediment on shallow seafloors that can be seen from space.As a result of scientific studies showing that bottom trawling kills vast numbers of corals, sponges, fishes and other animals, bottom trawling has been banned in a growing number of places in recent years. Now satellite images show that spreading clouds of mud remain suspended in the sea long after the trawler has passed.

But what satellites can see is only the “tip of the iceberg,” because most trawling happens in waters too deep to detect sediment plumes at the surface, say scientists speaking a symposium session called Dragnet: Bottom Trawling, the World’s Most Severe and Extensive Seafloor Disturbance at the American Association for the Advancement of Science 2008 Annual Meeting February 15. Speakers at the session include Dr. Elliott Norse, President of Marine Conservation Biology Institute in Bellevue WA; John Amos, President of SkyTruth in Shepherdstown WV, Dr. Les Watling, Professor of Zoology at the University of Hawaii in Manoa HI; and Susanna Fuller, Ph.D. Candidate in Biology at Dalhousie University, Halifax NS.

The Effect of Trawling the Seafloor for Ground...

The Effect of Trawling the Seafloor for Groundfish. (A) The coral community and seabed on an untrawled seamount. (B) The exposed bedrock of a trawled seamount. Both are 1,000–2,000 meters (1094–2188 yards) below the surface. (Photo credit: Wikipedia)

“Bottom trawling is the most destructive of any actions that humans conduct in the ocean,” said Dr. Watling. “Ten years ago, Elliott Norse and I calculated that, each year, worldwide, bottom trawlers drag an area equivalent to twice the lower 48 states. Most of that trawling happens in deep waters, out of sight. But now we can more clearly envision what trawling impacts down there by looking at the sediment plumes that are shallow enough for us to see from satellites,” he said.

“Bottom-trawling repeatedly plows up the seafloor over large areas of the ocean” said Mr. Amos. “Until recently, the impact was basically hidden from view. But new tools — especially Internet-based image sites, like Google Earth — allow everyone to see for themselves what’s happening. In shallow waters with muddy bottoms, trawlers leave long, persistent trails of sediment in their wake.”
Susanna Fuller studies impacts of trawling on sponges in the Northwest Atlantic Ocean. “Seafloor animals such as glass sponges are particularly vulnerable to bottom trawling,” said Ms. Fuller, a graduate student of Professor Ransom Myers. Dr. Myers, who died last year, had published a series of papers showing that overfishing has eliminated 90 percent of the world’s large predatory fishes and is devastating marine ecosystems.

“What is amazing is the level of damage these types of animals have suffered, after the cod fishery in Canada was closed. We immediately started trawling deeper with no restrictions, and continue to do so,” she said. “There are ways to catch fish that are less harmful to the world’s vanishing marine life. We need to start protecting the seafloor by using fishing gear, besides bottom trawls, especially in the deep sea. It’s the only thing left,” she said.

“For years marine scientists have been telling the world that fishing has harmed marine biodiversity more than anything else,” said Dr. Norse. “And it’s clear that trawling causes more damage to marine ecosystems than any other kind of fishing. Now, as the threats of ocean acidification and melting sea ice are adding insult to injury, we have to reduce harm from trawling to have any hope of saving marine ecosystems,” Dr. Norse said.

Scientific findings about trawling impacts have led to increasing restrictions on this industrial fishing method. In 2005, the General Fisheries Commission for the Mediterranean banned trawling in the Mediterranean Sea below depths of 1,000 meters, and the United States closed vast deep-sea areas off Alaska to bottom trawling. In 2006, the United Nations General Assembly began deliberations on a trawling moratorium on the high seas, which cover 45% of the Earth’s surface, and South Pacific nations effectively put an end to trawling in an area amounting to 14 percent of the Earth’s surface.

There are tens of thousands of trawlers worldwide. They fish for shrimp and finfishes. Some bottom trawling operations catch 20 pounds of “bykill” for every pound of targeted species.

Source:Bottom Trawling Impacts On Ocean, Clearly Visible From SpaceScienceDaily,  Feb, 2008

Consumer Demand for Fish Depletes the Ocean’s Resources

Ocean fish are the last wild creatures that people hunt on a large scale. We used to think of the ocean’s bounty as endless, until recently — we have now discovered its limits. Between 1950 and 1994, ocean fishermen increased their catch by 400 percent by doubling the number of boats and using more effective fishing gear, according to the Monterey Bay Aquarium’s Seafood Watch.

Chinese cuisine Shark fin soup image

"I don't blame the fishermen for this," says marine biologist Sylvia Earle. "We — the consumers — have done this, because we have a taste for fish and 'delicacies' such as shark-fin soup".

In 1989, the world’s catch leveled off at a little more than 82 million metric tons of fish per year. We have reached “peak fish,” and no amount of boats will help us catch more. Today, only 10 percent of all large fish — both open-ocean species (including tuna, swordfish and marlin) as well as the large groundfish (such as cod, halibut, skates and flounder) — are left in the sea, according to research published in National Geographic.

“From giant blue marlin to mighty bluefin tuna, and from tropical groupers to Antarctic cod, industrial fishing has scoured the global ocean,” lead author Ransom Myers told National Geographic. “There is no blue frontier left. Since 1950, with the onset of industrialized fisheries, we have rapidly reduced the resource base to less than 10 percent — not just in some areas, not just for some stocks, but for entire communities of these large fish species, from the tropics to the poles.”

Co-author Boris Worm said, “The impact we have had on ocean ecosystems has been vastly underestimated. These are the megafauna, the big predators of the sea, and the species we most value. Their depletion not only threatens the future of these fish and the fishers who depend on them. It could also bring about a complete re-organization of ocean ecosystems, with unknown global consequences.”

“I don’t blame the fishermen for this,” says marine biologist Sylvia Earle. “We — the consumers — have done this, because we have a taste for fish and ‘delicacies’ such as shark-fin soup. Our demand for seafood appears to be insatiable … driven by high-end appetites. I’ve always believed that even when there is only one bluefin tuna left in the sea, someone will pay a million dollars to be able to eat it.”

Earle, who is also an author and sustainability advocate, points out that “most people also don’t know how bad it is for us to be eating so much fish, not only because of the destruction of an ecosystem vital to survival, but also because the big, predatory fish are full of the toxins and other pollutants that we cast into the oceans.”

“It’s not as healthy to eat fish as most people believe,” she says.

Three factors are responsible for the depletion of our oceans:

  • Coastal wetlands are a fertile habitat for fish and shellfish but also popular places for people. More than half of the world’s people live near a sea coast, which places most of our large cities next to the ocean. Sewage, oil, chemicals and agricultural fertilizer pollute bay waters. Paved surfaces near wetlands and tidal areas increase storm-water runoff.
  • Trawling and dragging are fishing methods that destroy habitat by dredging up the sea floor. Some trawlers put rockhopper gear, including old tires, along the base of their nets in order to roll over rocky reefs, giving sea life no place to hide. Dredges drag nets with a chain mesh base through soft sand or mud to catch scallops and sea urchins, crushing other life on the seafloor and damaging places where fish feed and breed. Some scientists believe that fishing with rockhoppers and dredges harms the ocean more than any other human activity.
  • According to the United Nations Food and Agriculture Organization, one in four animals caught in fishing gear dies as bycatch (unwanted or unintentional catch). Tons of fish are tossed out because they’re not what the fishing boat was after, have no market value or are too small to sell. Bycatch often takes young fish that could rebuild depleted populations if they were allowed to grow up and breed. It is estimated that for each pound of shrimp caught in a trawl net, an average of two to 10 pounds of other marine life is caught and discarded as bycatch.

Some seafood can be sustainably farmed. Clams are raised in special beds on sandy shores, where their harvest does little to disturb the ecosystem. Oysters and mussels are often raised in bags or cages that are suspended off the seafloor, doing little damage during harvest.

Many farmed fish such as salmon, however, are grown in net pens, like cattle in a feed lot. This is as environmentally damaging to the ocean as cattle feed lots are to land. Additionally, mangrove forests have been cut down and replaced with temporary shrimp farms that supply shrimp to Europe, Japan and America, until the water becomes polluted.

This article was first published on August,10 2011 by Shawn Dell Joyce – Consumer Demand for Fish Depletes the Ocean’s Resources – The Paramus Post – News and Lifestyle Webzine.

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Lessons From Diving with Whale Sharks

Published on: July, 21st 2011 by Keith Addis, President of the board of directors at Oceana, Huffington Post – Lessons From Diving With Whale Sharks.

For the past couple of days, I’ve been side by side with hundreds of the biggest fish on Earth – Whale Sharks.

I’ve just returned from an incredible adventure in Cancun, Mexico, where every summer hundreds of these majestic giants gather under the full moon to feed on billions of fish eggs.

Whale shark Tofo MozambiqueI was in Belize a year ago where we encountered two Whale Sharks, but it was absolutely amazing to be swimming in the middle of an estimated 300 whale sharks within about a one-square mile area. It’s a deeply spiritual experience to be so close to these massive, domino-patterned leviathans, often flanked by giant manta rays.

Observing these spectacular animals in the wild is a wake-up call for us all that sharks around the world, including these giants, need our help. Sharks are being hunted ferociously for their fins, primarily for shark fin soup. Millions are inhumanely killed every year, the result being that many species are now threatened with extinction.

As apex predators, sharks play a vital role in maintaining the health of marine ecosystems everywhere. Sharks are slow-growing, late-maturing, long-lived and give birth to very few offspring during their life cycles, making them extremely vulnerable to overexploitation.

Without sharks, the ocean can and will get out of balance quickly, as was the case off the coast of North Carolina. According to a study published in Science Magazine by the late Dr. Ransom Myers, the disappearance of sharks there led to an explosion in the population of rays, which have subsequently wiped out virtually all the bay scallop fisheries — and the fishermen whose livelihoods had depended on the health and sustainability of this resource for over a century.

The good news is that the United States has made great headway in shark conservation in recent months. At the end of 2010, Congress passed the Shark Conservation Act, which prevents shark finning in U.S. waters.

But while shark finning is illegal in the U.S., current federal laws banning shark finning do not adequately address the issue of the shark fin trade. As a result, fins are being imported to the U.S. from countries with limited to zero shark protections in place. Legislation banning the sale and possession of shark fins passed recently in Washington, Oregon, Hawaii and Guam and is pending in California.

I’m really hoping that California follows the lead of its neighbors. Ending the trade of shark fins in the state would continue our country’s reputation as a leader in shark conservation and send a signal to the world that shark fins belong on a shark’s body, not in soup.

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