Garbage Trashes Deep Ocean Abyss
Filed under: Discovery,News & Resources
Although fish use this debris as their habitat, this prawn trap is still catching crabs. M. Love, Marine Science Institute, University of California, Santa Barbara
Way down below the ocean is a giant garbage heap. You’ve heard of the floating oceanic garbage patches. Now meet the deep sea garbage dumps.
(From Discovery News / by Larry O’Hanlon) — Marine biologists have conducted their first on-location survey of trash accumulating in deep canyons off the coast of California and found lots of fishing gear, plastic debris, beer bottles and even a kitchen sink. Some of the debris has been down there so long it is even serving as homes for fish and other creatures.
“It’s part of the habitats being studied, either providing a habitat or damaging it by scouring or ghost fishing,” says fisheries biologist Diana Watters of National Marine Fisheries Service. Ghost fishing is what marine biologists call the unfortunate tendency of lost fishing gear to go right on catching and killing fish and other marine life.
Although all of the debris is unwelcome in these otherwise pristine places, some of it appears to be less harmful when sitting on the sea floor than when it is floating on the ocean’s surface or hanging somewhere in between, said Watters, the lead author of a paper on the survey that appears in the January issue of the journal Marine Pollution Bulletin.
Floating debris has a way of snagging fish, birds, sea turtles and marine mammals, as well as ending up filling the bellies of these same animals.
Because it costs a lot of money to dive into the deeper waters and learn what’s down there, Watters and her co-authors conducted their survey by reviewing extensive video footage collected since 1993 by two cameras on the National Oceanic and Atmospheric Administration’s manned submersible vehicle Delta.
The primary purpose of the Delta’s dives was to survey fish in depths from 20 to 365 meters (65.6 to 1197.5 feet). The same video documentation, however, also revealed ocean bottom trash.
The new survey has already been tapped by others working to protect fish and fisheries.
Staff of the Monterey Bay National Marine Sanctuary (MBNMS) recently used the survey data to return to one surveyed location with a much smaller, more maneuverable Remotely Operated Vehicle (ROV). At a depth of 100 meters (328.1 feet), they found a rocky reef adorned with large corals — as well as lots of fishing debris.
“We were testing our methods,” explained Karen Grimmer, MBNMS’s deputy superintendent. “We went right to the coordinates (in the survey), and we saw all this monofilament line crisscrossing this beautiful reef.”
Because some animals were actually making use of some older debris, it may be debatable if all of it should be removed — assuming that’s even feasible in some very deep water locations, Watters said to Discovery News.
A practical approach that is being considered now by MBNMS is to build cooperation between the Sanctuary managers and fishermen, so that any new loses of fishing gear are quickly reported, said Grimmer.
That way the gear can be retrieved –- a win-win, since the fishermen get their gear back and fewer marine creatures would be needlessly killed by lost traps and lines.
