Deep-sea corals: out of sight but in harm's way

Known as "sea corn" or "red trees," Primnoa resedaeformis is the most plentiful deep-sea coral species in the waters of Nova Scotia

By Environmental News Network staff

More than half of the world's deep-sea coral reefs have been destroyed, warned scientists at the First International Symposium on Deep Sea Corals in Halifax, Nova Scotia.

Amid a growing debate over the impact of modern fishing practices, experts from around the world met earlier this month to review and synthesize all aspects of deep-sea, cold-water coral biology, ecology and conservation.

Until recently, few people knew that deep-sea corals even existed.

"The conference cemented the realization that these are true coral reefs," said Martin Willison, a conservation biologist at Dalhousie University in Halifax.

Coral reefs have long been viewed as a tropical phenomenon. "(Most) literature about corals describes them as restricted to tropical regions," Willison said. "That is an error."

In the tropics, corals grow at shallow depths, Willison explained. "They receive food directly from the photosynthesizers, often making it possible for them to survive without filtering food from the nutrient-poor tropical waters in which they (live)."

Unlike reefs that thrive in warm waters, deep-sea corals grow without sunlight at cold temperatures and use filters to collect most of their food.

Generally found along the continental shelf at depths of 650 feet or more, deep-sea corals may be disappearing faster than their tropical cousins, according to scientists.

While tropical reefs face a variety of threats, including global warming, coral bleaching, damage from fishing practices and coastal pollution, most harm to deep-sea corals comes from bottom-trawling fisheries, Willison noted.

Many scientists believe the devastation of deep-sea corals by bottom trawlers is responsible for the decline of major fisheries such as cod.

"In one pass of a bottom trawler, the great majority of bottom corals can be removed," Willison said. "In Australia and New Zealand, fisheries using dragged gears have completely cleared corals from the rocky tops of seamounts, and the fish that were once abundant among the corals have disappeared."

So far, Norway is the only country that protects its deep-sea corals by restricting bottom trawling in an area of about 40 square miles, where some of richest coral reefs are found.

Conference participants formed a task force to increase public awareness of deep-sea corals and increase protective legislation for ancient underwater communities.

"It looks as though, if we close areas to bottom trawling, (deep-sea corals) can grow back much faster than we thought," Willison said.

"Still," he added, "that is less than one inch per year."

Copyright 2000, Environmental News Network, All Rights Reserved

Age of Aquarius: Undersea lab immersed in coral reef research
July 24, 2000
Pew floats marine commission to assess America's oceans
May 30, 2000
Fiji fouled by coral reef bleaching
April 26, 2000
Coral provides clues to climate change
February 7, 2000

Bottom trawlers decried as ocean clear cutters
Gulf of Maine: America's first ocean wilderness?
Undersea mountains yield living 'fossils'
Scientists go 3,000 feet deep for cures
Scientists seek to understand underwater forests

First International Symposium on Deep Sea Corals
Nova Scotia's Deep Sea Coral

Note: Pages will open in a new browser window

External sites are not endorsed by CNN Interactive.