Alaska's Coral Gardens
INTRO: Deep on the bottom of the sea, in one of the most remote parts of Alaska, let alone the planet, lie some of the most beautiful coral gardens the world has—for the most part—never seen. And now these same coral beds have taken center stage in a battle to protect the waters off Alaska from overfishing. Doug Schneider has more in this week's Arctic Science Journeys Radio.
STORY: More than 1,000 feet beneath the ocean surface, and hundreds of miles from the closest city, Bob Stone of the National Marine Fisheries Service lies flat on his side, cramped into a two-person submersible, and peers out a small porthole. Beyond the one-and-a-half-inch thick Plexiglas™ window is a world steeped in darkness. As the submersible reaches the bottom of a submarine canyon, the pilot turns on the floodlights and a video camera. Suddenly, Stone's world is filled with the truly amazing colors and fantastic shapes of a deep-sea coral garden.
STONE: "It reminded me very much of places I'd been in the tropics, both in terms of colors and structure of the corals. Some of them were low lying, some of them were high, and some looked like trees and some looked like bushes. Most of them are orange, but there were other colors too. Some greens and purples and even some blue sponges."
But of course, this isn't the tropics—not even close. This is Alaska's Aleutian Islands, 800 miles west of Anchorage. The only way to get here is a three-day steam aboard a research vessel. Stone says the trip was well worth the effort, because there's much to be discovered about corals that inhabit the world's high-latitude waters.
STONE: "We've certainly found some new animals out there, and I think we have only just brushed the surface, really. My personal feeling is that there is probably many species of sponges that people have never seen before."
Like their tropical cousins, Alaska's corals occur in a variety of colors. But that may well be where the similarity ends.
STONE: "They're actually quite different. We don't know much about cold-water corals, but we certainly do know that they grow much slower. They feed differently. They don't form coral reefs because they don't have this intricate symbiotic algae living in their tissues."
On a more basic level, Stone hopes to learn just why such a diverse variety of corals exists at all so far north.
STONE: "The Aleutian Islands, at least in terms of coral and sponges, seems to be very diverse. Our general knowledge for many years has been that diversity is pretty much something that is limited to tropical waters and that the further north you go toward the pole, diversity is much less. In that regard, the Aleutian Islands certainly appear to be an anomaly, and we're not sure why. It might be as simple as this is a fabulous source of good clear water with lots of food in it."
Stone and other scientists from the NOAA's Auke Bay Laboratory in Juneau, Alaska, first discovered the coral gardens in 2001. Discovered might be too strong a word. Scientists have long known the seabed off Alaska supported corals. But no one had ever been to the deep seafloor and seen them firsthand. Instead, evidence of coral came to the surface inside huge trawl nets fishermen drag along the ocean floor. According to National Marine Fisheries Service data, bottom trawlers hauled up about one million pounds of sponges and coral each year between 1991 and 2001. Ben Enticknap is a fisheries project coordinator with the Alaska Marine Conservation Council. He says bottom trawlers are destroying centuries-old habitat essential to sustaining Alaska's fish stocks.
ENTICKNAP: "We're primarily concerned about the effects of bottom trawling. What's happening is that they're dragging large rock-hopper gear and roller gear, which are like large airplane tires, and sometimes nets with just chain foot-ropes across the seafloor. It not only catches the target fish, which are cod and Atka mackerel, but catches lots of corals and sponges and other seafloor invertebrates that are providing important habitat refuge for commercial fish species."
The group failed in a recent attempt to convince the North Pacific Fishery Management Council, a group of mostly commercial fishermen who regulate fishing in Alaska's federal waters, to adopt measures aimed at protecting coral. Now the group hopes images that show Aleutian Island coral beds trawled bare and nearly void of fish will rally public support to protect these habitats.
ENTICKNAP: "It really just brings to life up here on the surface what's going on down there on the seafloor. When I can show people coral gardens it really captures people's attention. I can talk about it all day long but these images are truly valuable in relating the message."
While resource managers and environmental groups battle over how to protect Alaska's corals, Bob Stone plans to return to the Aleutians next summer to look for more coral. So far he and his colleagues have found coral gardens down to about 350 meters or 1,200 feet. On the next trip, Stone plans to look for these gardens at even deeper depths.
OUTRO: This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program and the University of Alaska Fairbanks School of Fisheries and Ocean Sciences. I'm Doug Schneider.
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Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks. The shortcut to our ASJ news home page is www.asjnews.org.
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of corals with mackerel in an untrawled seafloor in Seguam Pass, Aleutian
Islands. (Courtesy Harold Zenger, Alaska Fisheries Science
Center and Alaska Marine Conservation Council) 3.35 MB
Video of nearby trawled seafloor near Seaguam Pass, Aleutian Islands. (Courtesy Harold Zenger, Alaska Fisheries Science Center and Alaska Marine Conservation Council) 2.58 MB
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Free book: Living Marine Habitats of Alaska
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