Seaweed: More Questions

continued from Homepage

The PDT is discussing questions about best harvest and oversight practices. Rockweed is currently managed through a combination of statutes and regulations, including harvesters permits, buyer’s licenses, and associated fees; regulations specifying that harvesters must leave a minimum of 16 inches of rockweed above the holdfast with the lowest lateral branches undisturbed, and requiring harvesters to record daily harvest (area, method, species, weight, etc.) and submit these records to the DMR monthly.

In addition, in 2009, Maine statute established the Cobscook Bay Rockweed Management Area, which divides the bay into 36 management sectors allocated to harvesters, who must submit harvest plans that include a biomass assessment survey to receive a sector allocation. Harvesters fishing under an approved harvest plan may remove a maximum of 17 percent of the annual harvestable biomass, must make a reasonable effort to minimize bycatch mortality, and cannot harvest in the designated closed areas.

According to a draft document – still in development by the PDT – the aims of the plan are to create an adaptive harvest plan based on available scientific data, establish harvester training/certification to qualify for a harvesting license or its renewal, establish area-based management, adopt harvesting practices that maintain healthy, viable A. nodosum strands, adopt harvesting practices that maintain species diversity and richness over the long-term, establish research and monitoring programs that include representative harvest areas and control areas for comparative studies, recognize spatial differences in A. nodosum biology and population structures, establish management practices that require licensee accountability, adopt enforceable regulations that promote self-regulation and include consequences to encourage compliance, and utilize best available scientific data and promote continued research to inform management.

The goal is to develop a statewide rockweed plan for review by the state legislature’s Joint Standing Committee on Marine Resources by January 2014.

The PDT held its most recent meeting on Sept. 12. It plans to meet again on Oct. 3, Nov. 7 and Dec. 5 to discuss and finalize draft measures. All meetings are held in Hallowell.
Rockweed and urchin are the first of the state’s fisheries to come under the DMR’s management plan process.

Linda Mercer, director of the DMR’s Bureau of Marine and Searun Science, is the DMR’s point person in the rockweed plan’s development. She said the DMR’s goal is to review possible measures needed in addition to, or to improve, those already in place.

“We want to manage the fishery and resource on a coastwide basis,” said Mercer. “We don’t know that we’re doing enough at this point.” The Cobscook Bay plan, she said, was driven by an increase in harvesting by U.S. fishermen hired by the Nova Scotia-based Acadian Seaplants, whose arrival in the area heralded a jump in landings.

The PDT is reviewing how other countries – such as Norway, Ireland and Canada – manage their rockweed resource, Mercer said. “We’ll be taking a comprehensive look and seeing what’s appropriate for here,” she said. “Some concerns are not just about the sustainability of rockweed itself, but of the ecosystem it supports, the community of animals and other plants it supports. So we’re looking at it from a broader ecosystem perspective.”

The PDT is trying to get input from individual harvesters through its industry members, she noted.

The PDT is also looking at socioeconomic aspects of the industry, she said.“There’s not a lot of information on the economic component of the seaweed industry,” she said. “We have dockside landings, we have estimates of the value of the industry. But we don’t have good value-added documentation. Companies can add that information.”

Still, the drafting process comes with a pretty good amount of information, she noted. “There’s been a lot of work done here in the Gulf of Maine on rockweed over the years,” she said. “So there’s a lot of background information.”

A number of seaweed species in the gulf have value, she said. But rockweed is a high-volume product because of the various uses it has. PDT members said the Maine process benefits from information gained through studies in this state and from the experience of other countries.

“We don’t need to reinvent the rule,” said Robert Morse. “This is very positive – if it’s carried through properly.”

Morse is a marine engineer who founded Atlantic Laboratories, doing business as North American Kelp, in 1971. According to its website, the company harvests and processes several types of kelp year-round with a regular crew of 10 that swells to 35 during peak harvesting seasons.

The question of what “sustainable yield” means, and its implications for the resource, the ecosystem, and the industry, remains central to the PDT’s deliberations.

Morse said the rockweed fishery is protected by the current 16-inch cutting height and capable of expansion under a sector system, using mapping and monitoring technologies that could result in more jobs and a better-developed, sustainable fishery.

With regard to the cutting height, Larch Hanson disagreed. Hanson said he advocates for doubling the cutting height. Hanson is founder of Maine Seaweed in Steuben, a family-owned business on Gouldsboro Bay that practices hand-harvesting and drying techniques. He has been in the business for four decades.

“Rockweed grows by branching, and it grows an average of 3-4 inches per year,” Hanson said in an email. “If you measure the distance between vesicles, you can see the rate of annual growth.  When I count stems on a rockweed plant that is five feet long, I count (on average) three stems at 5 inches up from the holdfast, nine stems at 16 inches (this is the present statutory cutting height), 28 stems at 24 inches, 66 stems at 36 inches, and 99 stems at 48 inches.  The plant doesn’t begin to feel thick and substantial in my hand until I reach a level that’s about 32 inches up from the holdfast.  Thirty-two inches is a plant that has grown for 7-10 years.  Sixty inches is a plant that has grown for 13-20 years!  In other words, if I take a 60-inch plant in hand and cut it at 32 inches, I am cutting it back 6-10 years!  

“Now picture this: A three-foot plant carries half of its biomass in the upper half of the plant.  A four-foot plant carries half of its biomass in the upper third of the plant.  Cutting a four-foot plant at 32 inches up from the holdfast means removing half of the biomass.  Can you see why I advocate raising the cutting height to 32 inches? And can you see why I advocate not cutting plants that are less than 36 inches long?  When I get done harvesting a bed, I want it to still look like habitat and shelter. Thirty-six-inch plants simply haven’t had time to develop stems for regeneration.  But don’t take my word for it.  Go measure a few plants and count vesicles and stems at various levels.”

George Seaver, a vice president at Waldoboro-based Ocean Organics, said the Maine Seaweed Council, formed in the 1990s by commercial harvesters, has played a foundational role in establishing harvesting guidelines to ensure the health of the resource.

Local environmental impacts of harvesting depend on whether it’s done properly or not, Seaver said: “Rockweed can be commercially harvested (more like grazing) in such a way that the same beds can be revisited every year or every two years or every three years. It usually depends on the logistics of moving the harvested seaweed (and the harvesters themselves) to the processing plant and which option commercial harvesters use.

“The larger issue, with respect to the environmental or ecological impact, is the percent of the ecosystem that is affected. The most aggressive harvesting in an area, I think, was probably less than 3 or 4 percent of the rockweed in that bay system. Keep in mind that Mother Nature typically removes about 40 percent of the biomass per year. This percent is based on different studies around the edges of the North Atlantic Ocean. There are so many moving parts in the intertidal ecosystem – water temperature, invasive plants and animals, etc., that it is very difficult to be sure what is affecting what. I don’t know of any environmental impact that was reported or even suspected by scientists in the past 40 years from rockweed harvesting in Maine.”

Seaver said the industry acknowledges the importance of rockweed as habitat: “As the industry grows, we need to be thinking about this – and that’s why we have scientists in the group developing the management plan.”

Dr. Susan Brawley, a professor at the University of Maine’s School of Marine Sciences whose research focuses on seaweed, and a member of the PDT, defined the concept of sustainability and the parameters that help to determine a sustainable level of harvest as follows: “For sustainability, Ascophyllum harvest must not compromise the ability of the plant to regenerate, which is why it is so important to leave intact a substantial part of the lower section of the plant.  In sustainable harvest, which has a centuries’ old history in several areas of the North Atlantic (e.g., Scotland, Ireland), harvesting should represent a temporary disturbance that resembles the effects that typical, natural disturbances (storms, ice shear) have on Ascophyllum.

Defining Sustainability

Parameters of value in assessing sustainability would include 1) full recovery of Ascophyllum biomass and stature within a few years, and 2) maintenance of sufficient Ascophyllum canopy in harvested areas to sustain the ecological benefits of Ascophyllum canopy to other organisms – for example, protection of understory organisms from drying and temperature stress. Again, it is essential that the lower sections of plants are left intact by the harvesting procedures. 

“I’d like to note that Ascophyllum is only one of Maine’s rockweeds (closely related brown seaweeds belonging to a scientific family called the Fucaceae, and the others all are species of Fucus). Rockweed is not equivalent to Ascophyllum, but Ascophyllum is a rockweed.”

Dr. Brian Beal, professor of marine ecology at the University of Maine at Machias, said the PDT is not aiming to define sustainability per se as it works out management protocols.

“We have a very good model in what is happening in Cobscook Bay right now,” he said. “I think the discussion in the recent past has leaned toward using that as a template. I don’t know how we’ll tweak it. But that’s a very good place to start.”

A research team at Unity College, led by associate professor of biology Aimee Phillippi, has also been looking at rockweed and issues of sustainability. Phillippi noted that research and data analysis are ongoing, “but early results indicate that harvesting does not appear to have a negative effect on animals living in the sediments beneath the rockweed.”

Phillippi and her team of student researchers presented a poster on their research to date, last March at the international Benthic Ecology Meeting in Savannah, Georgia. According to their findings, the team wrote, “the utilization of a natural resource involves implications for the natural community. Growth rates of A. nodosum vary depending on location and age, but can be relatively high, reaching 20 centimeters a year or more, suggesting that recovery after harvesting can be rapid. When rockweed is removed at the holdfast, even after six years, harvested sites have not returned to pre-cut biomass. However, when cut higher, representing more realistically how harvesting occurs, biomass and canopy cover can recover after only one to two years. Harvesting regulations may aid recovery. In Maine, no more than 17 percent of the standing biomass may be harvested and during harvesting, 16 inches and the lowest lateral branch must remain.

“Despite these sustainable practices, environmentalists are concerned about the broader impacts of harvesting rockweed, especially those on the faunal communities.”

According to the DMR, rockweed was utilized by Native Americans and New England colonists for agriculture, food, and animal feed, in addition to non-food uses. Pre-1970s, industries were well-established in Canada, British Isles, France, Iceland, and Norway. In Maine, rockweed was traditionally harvested for fertilizer and packing material for seafood shipping. In the early 1970s, commercial-scale harvesting and processing began in Maine. Rockweed was processed for fertilizer, soil conditioner, and animal feed supplement.

Hand-harvesting methods use knives, machetes and sharpened rakes in the intertidal zone; mechanical harvesters are jet-propelled vessels with a boom cutter and pumping/netting apparatus, allowing the vessel to access more shallow, ledgy shoreline.

Annually, the DMR issues around 100 seaweed harvester licenses. There are about 115 waterfront and plant workers, for a total industry employment of 225 people. The figure includes non-rockweed harvesters. Rockweed typically comprises 90-plus percent of the total annual Maine seaweed landings. Statewide rockweed landings for 2010 were 12.7 million pounds, having a landed value of $253,525. The majority is processed into wholesale and retail products including fertilizer, soil conditioner, animal feed supplements and nutritional food and health items for human consumption. With a total estimated value of $20 million per year, rockweed is one of Maine’s most valuable marine resources.

Rockweed is an intertidal, brown algae on North Atlantic shores, and a major component of intertidal habitat along Maine’s coastline. Individuals cling to rocks and other hard surfaces with a “holdfast” attached to a stem. Fronds grow from each basal holdfast, and the plant generally regenerates new fronds from the base when one of the larger fronds is damaged. Individual plants can reach six feet in length on sheltered shores.

At high tides, the rockweed canopy of floating fronds provides food, shelter and spawning habitat for a variety of animals, including small crustaceans, juvenile mussels, snails, whelks, periwinkles, and fish. These, in turn, attract feeding seabirds and shorebirds.