Saving Seafood

Artificial Reefs Take on a Towering Presence as Havens for Marine Predators

September 10, 2020 — The following was released by Duke University:

Acting like high-rise timeshares in the sea, shipwrecks and other artificial reefs can support dense populations of sharks, mackerels, barracudas, jacks and other large migratory marine predators essential to ocean health, according to a new study at 30 sites along the North Carolina coast.

Predator densities were up to five times larger at the 14 artificial reefs surveyed in the study than at the 16 nearby natural reefs that also were surveyed

Shipwrecks, especially those that rose between 4 and 10 meters up into the water column, were by far the fishes’ favorite. At some sites, they supported predator densities up to 11 times larger than natural reefs or low-profile artificial reefs made of concrete.

“These finding tell us two important things. One is that artificial reefs can support large predators, potentially supplementing natural reefs if the design and placement of the artificial reefs are strategic,” said Avery Paxton, research associate with the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science (NCCOS) in Beaufort, N.C., who led the study.

“The second thing it tells us is that when it comes to designing artificial reefs, there may be such a thing as a height advantage. We observed more fast-moving predators that live and hunt in the water column at the taller reefs in our study,” she said.

Climate change, pollution, development and other stresses have accelerated the decline of natural reef ecosystems across much of the world’s oceans in recent years, forcing large predators who formerly fed in the water column around the reefs to venture outside their normal migratory routes and native ranges in search of suitable alternatives.

Because these predators help maintain healthy and sustainable populations of species lower in the food web, providing suitable habitat for them as expediently as possible is critical, said Brian Silliman, Rachel Carson Distinguished Professor of Marine Conservation Biology at Duke University’s Nicholas School of the Environment, who collaborated on the study.

Read the full release here

Maine: How Seaweed Connects Us All

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

 

Maine: It’s shrimp season, but without the shrimp

December 27, 2017 — PORT CLYDE, Maine — Sitting between Glen Libby’s desk at Port Clyde Fresh Catch and the armchair where his brother’s old dog, Red, likes to nap are two boxes full of “The Original Maine Shrimp Cookbook.” This slim spiral-bound volume includes contributions from various members of the brothers’ immediate family, whose shrimping history dates back nearly four decades in this coastal town about two hours northeast of Portland.

Libby loves the small, delicate Northern shrimp, known fondly here as Maine shrimp, and so do customers at his processing and distribution plant. He bought $700 worth of the books to sell.

“I have sold two,” Libby said.

He is unlikely to sell many more. Not long after the cookbook was published in 2009, its central ingredient began vanishing from Maine’s waters. In 2014, regulators closed the shrimp fishery (the term that encompasses both the fishing grounds and those who work there). The hope was that the struggling species would replenish itself if left undisturbed.

So far, according to scientists who survey the Gulf of Maine annually, it has not. Their most recent data show Northern shrimp numbers at a historic low for the 34 years in which they have been counting the crustacean, Pandalus borealis. Egg production is down. Survival rates for larvae are poor.

Read the full story at the Boston Globe