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Trawling Leaves Lasting Scars on Deep Ocean Coral Habitat

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December 1, 2007

More than a decade after fishing stopped near the Corner Rise Seamounts in the North Atlantic,
researchers have found that the seafloor still has patches that are
almost completely devoid of life. During an expedition to study deep-sea
corals, Woods Hole
Oceanographic Institution (WHOI) biologist Rhian Waller and colleagues found that several coral communities were
extensively damaged, with evidence that the scars were caused by fishing
trawlers. Corner Rise is a cluster of ancient volcanoes
at least a half-mile below the sea surface and 1,200 miles from shore. Using a
remotely operated vehicle to survey the volcanic slopes, the research team
found broken branches of bubble gum corals, which usually grow in abundance atop seamounts. The entire top of Kükenthal Peak
was wiped clean; on Yakutat Seamount, the number of live corals was
negligible. Though fishing stopped many years ago, the summits “no longer
support habitat-forming corals in any significant numbers,” the biologists wrote
in the Journal of the Marine Biological Association of the United Kingdom. As fishing grounds close to shore become over-fished and
increasingly regulated, deep-sea habitats have become
more appealing for fishing fleets. At the same time, deep-sea corals grow very
slowly—perhaps an eighth of an inch per year—and some can live for thousands of
years. The combination of a stressed fishing industry and slow-growing corals,
the biologists note, adds up to trouble.
Related Links
» Oceanus Magazine: Coral Catastrophe on the Corner Rise

» Anthropogenic impacts on the Corner Rise seamounts,
north-west Atlantic Ocean

» Oceanus Magazine: Coral
Gardens in the Dark

» Molecular Ecology and Evolution Laboratory