By Jackie Dragon
There are some amazing places where discovery still awaits us – if we are careful to not blow them up before we even get there! The Bering Sea, up near the top of the world between Russia and Alaska, is one of those places. Here, new research, soon to be published in a peer-reviewed journal, from a first of its kind expedition down into the largest submarine canyons in the world found fragile corals that play an important role in the life-teaming ecosystem of the Bering Sea.
At 60 miles wide and nearly 9000 feet deep Zhemchug canyon is larger than Arizona’s Grand Canyon, as is Pribilof canyon, which cuts into the continental shelf just 25 miles south of St. George Island where Alaska Natives have lived on the bounty of the Bering Sea for millennia. Canyons like these are rare, occurring in only 4% of the world’s oceans, and they are important drivers in the highly productive zone coined “the green belt” by scientists.
Both of these “Grand Canyons of the Sea” revealed the existence of vibrant corals and sponges in their depths. The joint expedition into the canyons, which included explorers from Alaska, a National Oceanic and Atmospheric Administration scientist, and advisers from many of the world’s leading oceanographic institutions, confirmed the belief that the canyons contain coral and sponge habitat that plays an essential role for commercially important fish and other marine life.
At times the muddy abyss resembles the stark surface of the moon, but bursts of life come into view. Pacific ocean perch, king crabs, and other species were observed taking refuge in coral and sponge outcroppings. In the otherwise barren territory these corals and sponges provide fish and a host of other marine life with shelter and resting places, protection from predators and strong currents, feeding areas, nurseries for young fish, and spawning and breeding areas.
Explorers conducted 22 dives into the canyons in Deepworker submersibles, the smallest submarines in the world, finding 14 species of coral down to depths over 1000 feet. With high resolution video cameras the team systematically surveyed the canyons and documented the life in their depths. Carrying back to the surface the first ever glimpses of life in the canyons, explorers revealed colorful images one might not imagine when looking out over the dark, cold sea: translucent apricot-colored juvenile king crab, sponges cradling fish eggs, orange and white tie-died anemones, a cluster of six king crabs crowding a lively rock covered in basket stars, spotted rockfish hugging pink sea-fan corals, and a spectacular magenta octopus curled up asleep among the sponges at 826 feet.
Many of the species found were not previously known to exist this far north, representing a northern expansion in the scientific record and highlighting how little we know about the canyons. In fact, an entirely new species of sponge was discovered on the expedition, and fittingly named Aaptos kanuux – the Aleut word for heart. As far as we know this little sponge lives nowhere else on earth!
Scientists believe there are likely hundreds more deep-sea species still unknown to science and yet to be discovered in Alaska’s rich waters, and some of them may even contain invaluable chemicals with great potential for biomedical uses. Some of these slow-growing deep-water corals are hundreds or even thousands of years old. They may grow only millimeters a year and they are extremely vulnerable to human activities like fishing.
And fishing is a problem. Big fishing boats in search of big profits are fishing at greater depths than ever before, and trawling through the canyons in search of groundfish. Huge factory trawlers, capable of fishing many miles off-shore and processing their catch on board, drag nets over the shelf and slope of the canyons to catch pollock – the ubiquitous white fish better known as fish sticks and imitation crab meat.
Alaska Pollock, the nation’s largest fishery, brings in more than a billion dollars and takes on the order of a million metric tons of Pollock from the Bering Sea each year. But, in doing so, the large trawl nets often run over the sea-floor and demolish coral and sponge habitat in their path. Not surprisingly, the expedition into the canyons found trawl scars, large swaths of ground with broken corals and the strewn remains of previously valuable habitat.
The good news is that there are still areas in the canyons rich with corals and sponges. Add to that the fact that less than 5% of the annual Pollock catch over the past 5 years has been caught in the canyons and we think there is a good case for preserving this important habitat. We now know there is essential living habitat in the canyons, with a proven benefit to commercially important species and the ecosystem that supports them. We can only guess what other exciting and valuable discoveries will be made upon further exploration of the great canyons, if, that is, we don’t plow through them, destroying the life there before we even discover it. This area is too important to the ecology and the economy of Alaska to leave it open to destructive fishing. We can afford to move the fisheries out of the canyons, but there’s no telling what we might lose if we don’t protect part of this invaluable deep-sea habitat soon.
Jackie Dragon is an Oceans Campaigner at Greenpeace USA