We’re all familiar with the environmental damage that can be caused by clear-cutting rainforests. So it is unfortunate to hear that a similar scenario is being played out underwater, in our oceans. Research shows that trawling for fish can disturb the seabed in ways comparable to slash-and-burn clear-cuts.
Trawling is on the increase, in part because of improvements to fishing gear. Nets are dragged on the ocean floor to catch bottom dwellers like cod, shrimp, and scallops. As these species are overfished, trawlers go farther out to sea, or use nets equipped with rubber wheels to navigate rocky areas and coral banks that were once safe-havens.
Research has shown that ocean floors once complex in topography and rich in marine life have been scraped bare by trawling. As ocean floors are flattened, and sponges, corals, and giant kelps are damaged. Loss of habitat threatens an array of ocean life, including young fish. And sediment loosened by trawling clouds the water and reduces its oxygen content.
Researchers studying trawling have written that, “with the possible exception of agriculture, we doubt that any other human activity physically disturbs the biosphere to this degree.”
Remediating seafloor damage will probably involve limiting what kind of trawling equipment can be used in sensitive areas and establishing no-trawl zones as underwater wildlife sanctuaries.
We must balance the need to feed and shelter our population and to provide jobs with the desire to protect the environment. That’s why our policymakers need the best information science can provide—so that they can make informed decisions about critical environmental issues.
Web Links
Ploughing the Deep Sea Floor (Nature, September 23, 20123)
http://www.nature.com/nature/journal/v489/n7415/full/nature11410.htm
Disturbance of the Seafloor by Mobile Fishing Gear
http://onlinelibrary.wiley.com/doi/10.1046/j.1523-1739.1998.0120061180.x/abstract
Photo, taken on June 20, 2011, courtesy of Mike Baird via Flickr.