May 31, 2018 — Among Rachel Carson’s many literary virtues is this: she was a keen observer of seaweed. In The Edge of the Sea, Carson’s 1955 ode to America’s eastern seaboard, she extolled the “smooth and satiny” tendrils of horsetail kelp, the “fleshy, amber-colored tubers” of sea potato, the “paper-thin layers” of dulse. Scraps of Porphyra, she wrote, resembled “little pieces of brown transparent plastic cut out of someone’s raincoat.”
No intertidal dweller captured Carson’s imagination like Ascophyllum nodosum, a rubbery, olive-colored, ubiquitous macroalgae known widely on the Atlantic coast as rockweed. The biologist was most enchanted by rockweed’s double life—how its identity changed with the tides. When the ocean withdrew from the Maine beach, she noted, the seaweed lay limp; when the tide returned, the submerged plants stood erect, “rising and swaying with a life borrowed from the sea.” The diversity of these undersea jungles, whose canopies sometimes stretch taller than two meters, enthralled Carson. “Small fishes swim, passing between the weeds as birds fly through a forest, sea snails creep along the fronds, and crabs climb from branch to branch,” she wrote.
We are accustomed to thinking of seaweed as a stage, the undulant backdrop against which play the dramas of more charismatic fish and shellfish. Today, however, rockweed stars as lead actor in one of Maine’s strangest resource conflicts. Although seaweed harvesting is hardly a new industry—New England’s farmers have nourished their fields with “sea manure” for centuries—rockweed has lately become a valuable commercial product, an ingredient in everything from fertilizers to pet foods to nutritional supplements. In 2017, Maine’s rockweeders gathered nearly nine million kilograms and raked in over $600,000, roughly four times the haul in 2001.
Inevitably, not everyone is thrilled about the boom. As rockweed’s profile has grown, the controversy over its management has escalated, ascending through Maine’s legal system all the way to the chambers of the state’s supreme court. This seaweed struggle, and the fate of A. nodosum itself, hinges on a single question, patently absurd yet bizarrely complex: is rockweed, in defiance of logic and biology, really a fish?
Read the full story at the Smithsonian Magazine