Bottom trawling for fish stirs up billowing plumes of sediment that can be seen from space and destroys entire seafloor ecosystems, new imagery reveals.

The technique, used all over the world, is a way to catch fish in deeper parts of the ocean with huge, deep nets, now that many near-shore fish populations have been virtually wiped out from over-fishing. Several studies have shown the significant impact that trawling has on ecosystems, killing corals, sponges, fish and other animals.

New and previously released satellite images show the extent of the plumes of material kicked up. And a video of the seafloor reveals how trawling denudes an underwater world.

"Bottom trawling is the most destructive of any actions that humans conduct in the ocean," said zoologist Les Watling of the University of Hawaii. "Ten years ago, Elliott Norse (of the Marine Conservation Biology Institute) 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."

Watling presented his findings Friday at the annual meeting of the American Association for the Advancement of Science in Boston.

http://www.msnbc.msn.com/id/23258607/

Horrifying- A revealing image of why we're the scourge of the oceans.

The way its going there won't be any fish left within 50 years!

Some species are sure to remain, but we've been ignorantly destroying delicate habitats for much too long.

How are we doing with fish farms? Are they ok or is there a lot of pollution from them?

I'm not aware of pollution issues arising from the fish farming where I live. Carnivorous farmed fish like Salmon and Kona are not sea-friendly alternatives, because they still require a trawled diet of ocean fish.

You can find references to pollution in some articles like this one (http://www.care2.com/greenliving/safe-sustainable-fish-easy-greening.html)...not all fish farms are kind to the environment.

Farmed Shellfish
Most oysters and many of the clams and mussels we eat are farm-raised. These farms do little to disturb the ecosystem—hurray!—they even improve water quality (the mollusks work as filters) and since they must be grown in non-polluted water, these farms are often very involved in clean water initiatives.

Farmed Salmon
The bad news comes from fish raised in net pens, like salmon. Over-crowded pens pollute the water and fish become diseased—pollution and disease spread to wild fish, and antibiotics used also leak out into the water. Escapees can overtake wild habitats, and the fishmeal used for feed is often made with fish that contain toxins. Eating wild salmon is okay, check the guides below for the best choices.

Farmed Shrimp
In tropical countries, countless coastal mangrove forests have been cut down to make room for farms to satisfy the international demand for shrimp. This is not a sustainable practice—waste builds up in the farm ponds making them uninhabitable for shrimp. The farm moves on, leaving a destroyed coastal environment in its wake. Mangrove forests are crucial for protecting coastal areas, the prognosis here is bleak.

If more people make informed choices about their food purchases, I'd like to think destructive fishing practices can be reduced or even halted before we suffer more disastrous ecological collapses.

Eco-Friendly Seafood Selector (http://www.environmentaldefense.org/page.cfm?tagID=1521)

You can search here for data on specific species and habitats: IUCN Redlist (http://www.iucnredlist.org/search/search-expert)

More food for thought: Consumers Alone Can't Save Our Fish - Eco-marketing: Bait and switch? It'll take a boat load of votes, too. (http://thetyee.ca/Views/2007/02/16/Seafood/)