Washington, Feb 17 : New satellite images have shown that the plumes of sediment on shallow seafloors caused due to bottom trawling, are clearly visible from space.
Bottom trawling is an industrial fishing method that drags large, heavy nets across the seafloor, stirring up huge, billowing plumes of sediment on shallow seafloors.
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 have shown that spreading clouds of mud remain suspended in the sea long after the trawler has passed.
But, according to scientists, 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.
"Bottom-trawling repeatedly plows up the seafloor over large areas of the ocean" said John Amos, President of SkyTruth in Shepherdstown, West Virginia.
"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," he added.
"Bottom trawling is the most destructive of any actions that humans conduct in the ocean," said Dr. Les Watling, Professor of Zoology at the University of Hawaii.
According to Watling, each year, worldwide, bottom trawlers drag an area equivalent to twice the lower 48 states of the US.
"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.
According to Susanna Fuller, a graduate student of Professor Ransom Myers, the impacts of trawling on marine life is quite evident.
"Seafloor animals such as glass sponges are particularly vulnerable to bottom trawling," she said.
According to Dr. Elliott Norse, President of Marine Conservation Biology Institute in Bellevue, Washington, "For years marine scientists have been telling the world that fishing has harmed marine biodiversity more than anything else."
"And it's clear that trawling causes more damage to marine ecosystems than any other kind of fishing," he added.
The danger to marine ecosystems due to bottom trawling can be minimized if proper fishing techniques are used.
"There are ways to catch fish that are less harmful to the world's vanishing marine life," said Fuller. "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 added. "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," said Dr. Norse.