|
|||
|
|
|||
Subscribe to Nature Conservancy Magazine |
In underwater laboratories off the California coast, marine scientists are taking land-based conservation strategies to sea to protect giant kelp and the forest ecosystems that lie hidden beneath the waves.
By Jennifer Winger
Launch the photo essay featuring giant kelp!
Just offshore of the Pacific coast of North America, a thin ribbon of green runs from Santa Cruz to southern Baja California. This rich forest habitat is giant kelp — a slim aquatic plant that fuels a massive amount of marine productivity. With its vertical reach and frond-laden stalk, kelp transforms the water column into a complex habitat that houses otters, fish nurseries and a host of invertebrates.
In the 1930s, culinary, pharmaceutical and scientific communities began harvesting kelp for its algin — a thickening agent used in many foods and cosmetics. Today, kelp is also harvested for aquaculture. Abalone farmers may harvest up to 20 tons of kelp every other day to feed the hand-sized mollusks on their bay-side farms. The plant itself is resilient, but scientists began to wonder whether such harvesting could take a toll on other species that live in the kelp canopy.
“Driving down Highway 1, you can see giant kelp running the length of the coast,” says Mike Beck, senior marine scientist for the Conservancy. “It’s an iconic marine habitat, but it’s rarely studied.”
To examine the effects of canopy loss on kelp communities, the Conservancy leased 1,700 acres of kelp forest over 15 linear miles of the Big Sur and San Simeon coasts to use as underwater laboratories. Working with the University of California at Santa Cruz, the Conservancy partnered with The Abalone Farm Inc., a local producer of farm-raised abalone, to experimentally cut Conservancy kelp beds so scientists could determine how the size and season of harvests would affect vulnerable species like juvenile rockfish that mature in the canopy, concealed from predators.
As one of the biggest kelp harvesters in the state trimmed Conservancy kelp beds from above using boats equipped with large hedge clippers, Beck and his team donned wet suits to examine the effects of the various harvesting treatments from below. Exploring an underwater forest may sound like the makings of a fairy tale, but for Beck and his team, the reality of surveying 2-centimeter-long rockfish in an aqueous environment was a little more Brothers Grimm.
“Getting through a kelp canopy can be difficult,” says Beck, whose team conducted four dives a day for three months straight, for three years running. “It’s like being in a normal forest, but up in the air, trying to navigate a straight path through the trees where the leaves and branches are thickest.”
Traversing tangles of kelp saddled with an oxygen tank and a 35-pound weight belt was the least of the divers’ worries. The lack of boat ramps between Morro Bay and Monterey made beach-launching a Zodiac a daily hazard; the 52-degree water made wearing a restrictive, inch-thick wet suit a must; and the proximity of the beds to one of the largest elephant seal colonies in the Northern Hemisphere made great white shark activity a little too frequent.
But after three years of research, scientists have come up with a strategy that yields as much kelp as current commercial practices but has less impact on kelp communities. Harvesting half of two kelp beds, rather than one whole bed at a time, allows displaced species to relocate. The Conservancy will work with local abalone farmers to implement the new technique on their own underwater leases, but the benefits of the study do not end there. During its lease, the Conservancy helped the state establish marine protected areas on Conservancy beds, so when the lease is up, the protection for kelp is not.
Launch the photo essay featuring the giant kelp!
Nature picture credits: Photo © Marc Chamberlain/SeaPics.com
Join The Nature Conservancy on