When many think of coral reefs, they think of Caribbean waters or perhaps the South Pacific. But there are corals off Alaska, too — as imperiled as they are beautiful.
These corals — surviving at depths from 540 to more than 9,840 meters below sea level — are some of the most diverse, dense, and pristine assemblages of cold-water corals in the world. Alaska corals form the basis of a rich and diverse undersea ecosystem on the otherwise mainly barren seafloor, and harbor a high abundance of coral species. In a dazzling array of life, delicate, fan-like hydrocorals in pink, yellow, orange and purple shimmer slightly in the ocean current, among them growing magenta, white and salmon-colored, many-branching, bushy or tree-like gorgonian corals. Flitting among the corals are bright orange, spike-finned rockfish and pink-scaled Pacific Ocean perch. Long-legged golden king crabs seek a high perch on corals, filtering the ocean currents for food, while an octopus might nestle in a crevice, its dark orange color providing excellent camouflage from predators. Many-armed sea stars of pink, orange or red navigate among the corals, feasting on the outer skin and the tentacled feeding cells of coral colonies. Diversity abounds, as corals protect these species and many more from predators, provide a safe place for brooding young and for juvenile fish to seek shelter, and act as a platform from which crabs or other invertebrates obtain food.
Amazingly, this multitude of life is found in the icy cold, dark waters below the gray, often stormy surface of Alaska’s oceans. Most people are surprised to learn of Alaska’s wide variety of corals, which occur in patches throughout the North Pacific and Bering Sea. High-density, lush and diverse coral “gardens” thrive off the central and western Aleutian Islands, while “forests” of red tree corals that grow to up to 10 feet tall are found off southeast Alaska near Sitka. Underwater volcanoes, called seamounts, host a wide variety of corals in the Gulf of Alaska, and submarine Bering Sea canyons deeper and longer than the Grand Canyon are home to the second-most dense and diverse areas of Alaska coral areas known. Alaska corals livefor hundreds or even thousands of years, growing and reproducing very slowly, in rhythm with the relatively unchanging environment of their ocean-floor habitat.
Unfortunately, these corals’ long lives and slow reproduction rates make them extra vulnerable to extinction, which they now may face — even as they’re just being discovered — due to widescale and hugely destructive commercial fishery activities, as well as climate change. More than 82,000 tons of cold-water coral bycatch continues to be hauled to the surface by fishers each year. Even more corals are damaged underwater by fishing activities, with long trenches of corals destroyed by the heavy doors used for trawling activities, as well as from being snagged by long-lines and pot fishing as they’re dragged along the sea floor. This destruction may be observed in nearly every submersible survey of cold-water coral areas.
But the greatest threat of all to cold-water corals is the emissions of greenhouse gases from burning fossil fuels. This, of course, causes ocean acidification and ocean warming, which are progressing especially rapidly in the North Pacific and Arctic oceans and threatening the survival of many calcifying marine organisms, including cold-water corals (and the plankton they eat). Shifting currents, increased freshwater input from melting sea ice and glaciers, and changes in upper and lower sea-level circulation patterns are already occurring, and they’ll progress rapidly if anthropogenic greenhouse gas emission continues under a business-as-usual scenario. Impacts on all marine life will be devastating, and the cold-water corals of Alaska will suffer massive casualties.
The Center is fighting to stop the destruction of cold-water corals, submitting a petition in 2012 to list 43 of these unique, often overlooked species under the Endangered Species Act. Fishery activities like trawling, long-lining and pot fishing must be stopped in areas of coral growth in order to protect these special species. The Center is also pushing for action to slow greenhouse gas emissions — especially carbon dioxide, which contributes heavily to ocean acidification and climate change. The loss of corals may dramatically impact a diversity of sea life that depends on Alaska corals, and many undocumented areas of coral growth may already be damaged beyond repair. It’s critical that these coral species be given federal protection if we value their continued existence and that of all the life they support.