Ghost nets -- nets lost or abandoned by fishing fleets -- are, along with other ocean trash, becoming a major ecological problem. They can continue killing fish, smothering reefs and generally wreaking havoc for decades. And they're really hard to find out in the open ocean -- at least until now. Now, NOAA scientists are developing ways to use remote sensing to find, track, and (hopefully eventually) clean up ghost nets. It's not a small challenge:
Thousands of miles from any human habitation, fishing nets hundreds of meters long and balls of net tens of meters across, lost or abandoned by their former owners but still an environmental hazard, foul huge swaths of the Pacific Ocean. However, the sheer mass of those so-called ghostnets floating freely in waves has come as an unpleasant surprise to NOAA scientists studying the phenomenon. Concentrated in relatively small areas of ocean by winds and currents, ghostnets present a hazard to wildlife, entangling marine mammals, turtles and sea birds and a largely unseen form of environmental pollution.
NOAA scientists are using satellite and other technologies to predict area where current and winds combine to funnel and accumulate debris into what are called convergence zones. However, a recent field deployment to confirm that the satellites accurately predicted the existence of a possible convergence zone off Hawaii gave a first substantive look into the severity of the ghostnet problem in the open ocean.
According to James Churnside, a researcher with the NOAA Environmental Technology Laboratory in Boulder, Colo., the bottom line is that, There is a lot more trash out there than I expected."