Just a few weeks ago, Phoenix food writer Laura McCandlish wrote about Maine's edible seaweeds, such as wakame and nori (see "Maine Seaweeds Make Good Eating," April 26). She also mentioned rockweed, by far the dominant algae in Maine, found on the rocky ledges of intertidal zones up and down the coast. It's not particularly edible (as McCandlish noted, its primary food-related use is as an insulator during lobster- and clambakes), but this brownish-green, leggy seaweed does serve as a habitat for more than 150 species of crustaceans, groundfish, sea urchins, shorebirds, and waterfowl.
Its long fronds, dotted with ovular air sacs, employ the energy of the sun to convert inorganic nutrients (such as phosphate or nitrate) into organic biomass, helping to maintain water quality and serving as food for bacteria, small marine invertebrates, and insects, which in turn feed birds, fish, and mammals. Juvenile lobsters and pollock (a species of groundfish heralded as bountiful) are known to forage and seek refuge in underwater forests of rockweed; during low tide, tangled masses of this coastal flora provide protection from the heat and sun for various larvae and crustaceans.
In addition to its ecological value, the abundant marine resource is also worth money — millions of pounds of rockweed are harvested every year to be used primarily as a supplement in animal foods and agricultural products. The state Department of Marine Resources estimates that the $20 million industry supports about 225 harvesting and processing jobs.
But some conservationists and landowners believe rockweed is being unsustainably harvested, thereby putting an entire coastal ecosystem at risk. The Dennysville-based Rockweed Coalition, founded in 2008, wishes to bring a "complete halt to all rockweed harvesting along the Maine coast;" a "Rockweed Registry" maintained by Downeast Coastal Conservancy lists more than 550 property owners from 12 towns who have publicly stated that they do not allow rockweed cutting on their property. (This registry, which is regularly distributed to commercial harvesters, has teeth because according to state law, the intertidal zone technically belongs to landowners.)
"We're looking at rockweed not as a product to be cut and processed but as a habitat," says Robin Hadlock Seeley, co-director of the Rockweed Coalition and assistant director for academic programs at Cornell University's Shoals Marine Laboratory in Maine. She notes there is limited information about the long-term sustainability and impact of rockweed harvesting, and that rockweed (unlike other seaweeds such as kelp) grows very slowly and is difficult to restore. She points to an already over-harvested marine resource to bolster her point. "If we're trying to bring back groundfisheries, the last thing you want to do is take away [groundfish] habitat. Rockweed is worth more in the water than in the net."
Rockweed cutters — who use a combination of handheld and mechanical tools — must obtain a seaweed harvesting license and are not permitted to cut fronds below 16 inches from their bases. In Cobscook Bay, regulations are even stricter thanks to management plan that's been in place since 2009 and includes a harvesting cap of 17 percent of the available rockweed.