Sugar kelp farming takes root in Vineyard waters

Study shows promise that the brown algae can be an eco-friendly cash crop for Martha’s Vineyard.

MV Shellfish Group sugar kelp farmed experimentally off Menemsha. — Rich Saltzberg

Sugar kelp is a brownish seaweed native to the northeast Atlantic, that grows in long ribbons. Technically it’s a type of algae. The Martha’s Vineyard Shellfish Group, using a grant from the Edey Foundation, is experimenting with rope-grown sugar kelp in the hopes of fostering a new winter industry on the Vineyard.

Unlike traditional farming, kelp farming requires no land use, no fertilizer and it’s impervious to drought. It could also help offset nitrogen pollution in Vineyard waters.

Although initial forays into kelp farming on the Vineyard had limited success, recent work by the Shellfish Group has shown more promising results.

Location is everything

In the company of researchers, The Times recently visited a kelp test site a few hundred yards off Menemsha Beach. Stretched below Vineyard Sound between two moorings was a shaggy kelp line that when hauled up, looked like a continuum of glistening mop heads. Martha’s Vineyard Fishermen’s Preservation Trust executive director Shelley Edmundson, said the kelp has grown vigorously since the rope was deployed on Nov. 28, 2017. At that time, Edmundson said, the kelp seedlings on the rope averaged four millimeters long. On Feb. 6, the average length had grown to 242 millimeters, Edmundson said. Significant growth for 70 days, she said.

Kelp needs current and cold to thrive, according to Edmundson, who with intern Otto Osmers, has been managing the Menemsha kelp experiment for the Shellfish Group. In the right location, wintertime Chilmark offers both conditions. A previous kelp experiment in Menemsha Pond resulted in a poor crop, because the water was too warm and the current was insufficient, Edmundson said. Warmer water “fouls” kelp by infesting it with tiny sea critters and sluggish water deprives kelp of nutrients and stunts its growth. Shellfish Group co-director Amandine Hall said that sugar kelp needs 1 to 2 knots of current to maintain a proper nutrient flow. Hall said she wasn’t completely confident warmth affected the pond kelp experiment and that lack of current alone likely accounted for the poor results. Sugar kelp naturally grows deep where the water stays chilly, she said, but in the frosty winter waters of the Vineyard it can be grown close to the surface, where it’s easier to access.  

Kelp farming is also good for water quality.

“It’s a plant so it absorbs nitrogen,” Hall said.

Last year the experiment in Menemsha Pond began with seeded string from the Woods Hole Oceanographic Institute (WHOI). The Shellfish Group’s aquaculture researcher David Bailey said the seeded string is basically “a PVC spool with string covered in small kelp blades. The farmer then wraps that string around a grow line.”

For three years, the Shellfish Group or its partners have also deployed kelp line off Eastville Beach in Oak Bluffs. The first year the Shellfish Group seeded its own rope at the Hughes Hatchery in Oak Bluffs, Hall said. WHOI provided the starter seed the next two years, and Cottage City Oysters, operated by Greg and Dan Martino, took over management of the kelp lines.

As a cold water crop, Edmundson and Hall both said they hope kelp farming can eventually help offset the downtime many Islanders who work on the water experience in the winter months. A few shellfish farmers have begun to dabble in kelp farming, Edmundson and Hall said.

In Menemsha, MV Fishermen’s Preservation Trust intern Otto Osmers has stewarded the kelp line through the winter so far under Edmundson’s supervision. He sees kelp as a sustainable vehicle to keep his family’s seafaring traditions alive.

“I have fished my whole life and many people in my family were commercial fishermen, and I [want to] continue that,” he said.

Osmers said he fishes with a student lobster license and also works on other boats out of Menemsha. He sees kelp farming as an alternative to “hammering the oceans” with pollution and habitat loss. “Also,” he said, it’s “pretty delicious.”

There appears to be a market for the locally sourced product.

Greg and Dan Martino sold kelp they grew to Beach Road Restaurant in Vineyard Haven last season where it was served with tuna tartar. Martha’s Vineyard Sea Salt has shown interest in flavoring one of its products with local kelp. Commercial possibilities for farmed kelp include use in beauty products, a smoothie ingredient, or as fertilizer.

As to where to find an active kelp farming industry in New England, Hall pointed to Maine.

‘Never dried, never dyed’

Maine’s seaweed powerhouse is Saco-based Ocean Approved. Hall described the company as “very, very encouraging” to the Shellfish Group’s nascent kelp program and voracious in its kelp consumption. She said Ocean Approved would be a potential buyer of kelp produced on the Vineyard.

“They can’t grow enough,” she said.

“In the New England states we are easily the largest processor,” Ocean Approved vice president of sales and marketing Fran Tighe said.

Tighe said it was possible his company would buy from Vineyard kelp farmers, should they emerge. Ocean Approved has bought from Rhode Island famers in the past. Because kelp must be processed within 24 hours of harvest, the logistics of getting the kelp to Saco in a timely manner will be a logistical challenge, Tighe said.

Ocean Approved produces and commercially sells shredded kelp and seaweed salad as well as cubed kelp for use in smoothies, pesto, and even salsa verde.

Tighe sat sets Ocean Approved kelp apart is that it’s American made, fresh, and undyed. Asian seaweed imported into the United States is dried and has been dyed green for marketability and is sometimes grown in questionable bodies of water that may harbor pollutants.

Ocean Approved blanches its kelp fresh, then flash-freezes it, Tighe said. The blanching process naturally turns the kelp from brown to green, he added. The company recently developed the slogan: “Never dried, never dyed,” Tighe said.