Feature Articles—September 2009 Issue
Canadian Expedition Highlights Importance of Deepwater CoralFirst-of-its-Kind Research Expedition in British Columbian Waters Documents Coral Forest’s
Role as Vital Habitat for Many Species
By James Gates
Marine Planning Communications Coordinator
and
Geoff Gillard
Communications Manager
Living Oceans Society
Vancouver, Canada
In June 2008, the Finding Coral Expedition set off to search for deepwater corals off the coast of British Columbia, Canada, but discovered a whole lot more. At five of the expeditions’ seven sites, the science team found at least 16 different kinds of corals, from small orange cup coral to red tree coral one meter high.
“We explored places no one has ever been before and saw spectacular corals that were absolutely blooming with life,” said Jennifer Lash, executive director of the Living Oceans Society and leader of the Finding Coral Expedition. “We found at least 38 species of fish and over 50 species of invertebrates.”
The expedition combined cutting-edge undersea technology with a team of world-renowned deepsea coral scientists who piloted one-man submersibles to depths of 500 meters to film, observe and gather coral samples.
Deepsea corals are fragile, long-lived, slow-growing animals that look somewhat like trees. Coral forests provide an important habitat for many species, including a variety of fishes.
Use of Manned Submersibles
The Finding Coral Expedition used two DeepWorker manned submersibles designed by Nuytco Research Ltd. (Vancouver, Canada).
Previous deepsea expeditions in British Columbian waters have relied on remotely operated vehicles, which have a limited ability to move to locations of interest. The DeepWorker subs gave the team the mobility to explore freely around the dive sites, and the subs’ clear field of vision allowed the pilots to pinpoint coral forest locations, see close up which coral species were most abundant, and observe how corals support thriving ecosystems teeming with life.
The scientists used the subs’ hydraulic manipulators, with a reach of 1.5 meters, to gather coral samples for classification by taxonomic experts.
The Living Oceans Society mounted the expedition in part to obtain high-resolution video, and the DeepWorkers proved to be excellent camera platforms. The subs were equipped with high-definition video cameras that recorded all the dives, capturing visual evidence of coral forests as well as the extensive trawl door ruts observed at several dive sites.
At mid-Moresby Trough in Hecate Strait, one scientist said: “It looks like the seafloor has been plowed.”
The high-definition video obtained from the dives will support the Living Oceans Society’s efforts to get the Canadian government to protect British Columbia’s deepsea corals. Globally, there is widespread scientific concern about the threat bottom trawling poses to deepsea corals and the ecosystems that they support. While the government has taken steps to protect British Columbia’s unique glass sponge reefs, there are currently no specific measures in place to protect deepsea corals. Fisheries and Oceans Canada (DFO) has said it requires more information before a coral protection strategy can be implemented, because there is insufficient data about corals, their locations and the species that depend on them. The Living Oceans Society hopes that the video evidence gathered from this expedition will change that.
“For too long, the focus from DFO has been on what we can take out of the ocean rather than the health of the ecosystem,” Lash said. “We have discovered that coral is an essential element for ocean health.”
A Needle in a Haystack
Finding coral in a vast area of ocean is akin to searching for a needle in a haystack.
The Living Oceans Society deduced where to dive for deepsea coral by analyzing bottom trawl observer data from 1996 to 2002. Trawlers are obliged to record what they catch, including unintended catches of fish, invertebrates and coral. The untargeted species, called bycatch, are thrown overboard dead or dying.
According to the observer data from those seven years, bottom trawlers threw away 2,300 tons of bycatch. Analysis revealed that there were 12 areas of high-density coral and sponge bycatch. Living Oceans used geographic information system technology to match the high-density areas with multibeam bathymetry data that showed the locations of steep slopes where coral would most likely grow.
Associated Sea Life
Corals are usually found perched on rocky slopes because they are suspension feeders, capturing and eating detritus and plankton carried in the current. During the expedition, the science team found that wherever there were vertical walls, there would likely be corals. And where there were corals, there was other sea life.
“I had never observed so many fishes associated with corals previously,” reported science team member Dr. Thomas Shirley, endowed chair for biodiversity and conservation science at the Harte Research Institute of Texas A&M University, Corpus Christi.
Shirley has participated in more than 40 research cruises and 12 submersible research projects. He and the rest of the science team are currently analyzing hundreds of hours of dive video and compiling an extensive species list that will include assessments of species relationships in the coral ecosystems visited by the Finding Coral Expedition. Initial observations concluded that many species of rock fish, both juvenile and adult, were found in association with red tree coral. Sea stars, brittle stars, sea lilies, anemones, shrimp, crabs, caprellid amphipods, other coral species and sponges were also found on or under corals.
Because the data gathered during the Finding Coral Expedition is an important contribution to the understanding of coral in British Columbian waters, the Living Oceans Society will share the expedition’s findings, video and data with universities, government agencies, fishermen and others to advance the world’s knowledge about deepsea corals.
James Gates is a writer living in Vancouver, Canada. He writes about issues that affect the health of British Columbia’s ocean waters.
Geoff Gilliard is the communications manager for the Living Oceans Society. He has been writing for several years on issues of sustainability.
Sea Technology is read worldwide in more than 110 countries by management, engineers, scientists and technical personnel working in industry, government and educational research institutions. Readers are involved with oceanographic research, fisheries management, offshore oil and gas exploration and production, undersea defense including antisubmarine warfare, ocean mining and commercial diving.
