I’m not a seaweed eater—at least that’s what I maintain. But it’s not precisely true. I consume seaweed every day in products that contain it, along with other ingredients, as do most people in the developed world. When I say I’m not a seaweed eater, I mean I don’t cook with it, and yet, writing this book has brought me to the world of culinary seaweeds, and I’ve eaten what others have prepared, and they’ve been good. Very good. But are they good for you?
Studies have shown that there remains much we don’t know about seaweed and human health. It is, in fact, a field of inquiry that is wide open and that will attract committed phycologists for years to come. We do know that extracts from seaweeds used in finfish aquaculture and in land-based agriculture contribute to human nutrition—a step away from eating seaweeds directly. Dr. Susan Brawley, a research phycologist who teaches at the University of Maine at Orono, contributed to the latest study of seaweed as food, which states, “It can be concluded that knowledge of the beneficial effects of algae and their extracts as food additives for humans lags far behind that on which diets have been formulated for commercially important species in aquaculture and agriculture.”
In other words, there’s more to do.
Among bits and pieces of many other foods, a small amount of evidence of seaweeds has been found in human middens thousands of years old, but despite our ability to plumb many of the secrets of our past, we have not figured out how to measure the effects of eating seaweeds today. Part of the problem comes from our accelerated technological ability to examine human nutrition and digestion with a scientific refinement we’ve never had before. Because we can apply advanced technology to understanding the foods we eat, we are reexamining what we thought we knew in everything, not just seaweeds.
Seaweeds do contain surprisingly high quantities and qualities of nutrients—vitamins and minerals, and amino acids, the building blocks of protein, and phytochemicals. These healthy components are in there, but the question is, can our bodies extract and use them? The dense dietary fibers found in seaweeds make it difficult for most people to digest them adequately to access the nutrition they contain. An exception is the Japanese people, whose food culture depends on the sea. They have developed, over centuries, gut flora that can break down and utilize seaweeds far better than people in most other cultures.
On the other hand, the fibers that act as roughage may aid in cleansing the human digestive tract for everyone and contribute to the health of intestinal flora. For instance, the alginates found in brown seaweeds have the capacity to absorb and remove toxins in the human gut and can be used in weight-control programs because they provide a sense of fullness.
One micronutrient that all humans can access in seaweeds is iodine. This is both a blessing and a caution, because a little is essential, but too much may cause harm. What’s too much? Japanese iodine intake from edible seaweeds is among the highest in the world, and a recent study estimated that the daily average intake of iodine per person in Japan was probably between 1,000 and 3,000 micrograms, whereas in this country the recommended daily allowance for an adult is about 150 to 200 micrograms. Foods other than seaweeds that supply iodine are some fish, milk products, grains, vegetables grown in iodine-rich soils, and iodized salt. Interestingly, milk’s iodine content may come from the cleansing of the teats of the cows with an iodine solution before milking as much as or more than from the summer pasture grasses they consume.
Japanese living in Japan are among the healthiest people in the world, despite their high iodine intake. They eat a lot of fish, a lot of seaweed, tofu, and vegetables in the cabbage family, and somehow this mix gives them a better chance at optimal heath than people in many other cultures have. But again, it may be the combination of these foods that’s salutary. For instance, both tofu, made from soybeans, and vegetables in the cabbage family restrict the uptake of iodine, and this probably buffers the high-seaweed diet.
Hijiki, the popular Japanese seaweed, has naturally elevated levels of arsenic, as does, to a lesser degree, Ascophyllum nodosum, the seaweed common on both sides of the Atlantic (as does rice grown in the southern part of the United States on fields that once produced cotton). Arsenic is a heavy metal that can cause acute illness and death, but seaweeds render inorganic arsenic, the most dangerous form, into organic arsenic, which is less toxic.
Many species of seaweeds are excellent collectors and concentrators of toxic metals and other pollutants, and they are routinely used in ports and bays and river mouths to improve water quality. This process is called phycoremediation, or seaweed fixing. Seaweeds render a number of toxins into less harmful forms as they assimilate them, but those used in phycoremediation are, of course, inedible. Some of the same species are harvested for use in food and in farm fertilizers, and because of this overlap, phycoremediation needs to be strictly monitored.
In early August 2009, along a broad stretch of holiday beach at Saint-Michel-en-Grève in Brittany, on the northwest coast of France, Ulva lactuca, the common green seaweed of the North Atlantic, lay in deep windrows on the shore. Over the decomposing mass a hot crust had formed, and beneath the crust was stirring a fierce poison.
When a horse and rider broke through, slipped, and went down, the horse died of pulmonary edema within minutes. The rider was saved by a man with a bulldozer who drove into the muck to scoop him out, unconscious. The poison was hydrogen sulphide, a quick-acting gas that builds up as a byproduct of anaerobic decomposition. Inadvertently, local farms had leaked nitrogen-based fertilizers into the bay through runoff from summer rains and from pig and cattle pens, and perhaps a water treatment plant built too close to the shore had overflowed. The seaweed proliferated with this nitrogen-rich diet, growing in deep layers on the beach, cooking its poison in the August heat.
The scene was terrifying. The sudden chaos. The thrashing of the dying animal. Before this accident finally drew the attention of the press, a man who was hired by the town to drive a truck piled high with this seaweed debris, in an effort to clean up the beach, died, as did two dogs playing at the edge of the shore.
The potential for this sort of tragedy exists in coastal communities around the world: a fast-growing seaweed in the shallows of a warming shore, highly responsive to unchecked nitrogen runoff, becomes weaponized.
What keepers of aquarium fish want in their tanks is a green habitat that isn’t eaten by the captive fish or fouled by recirculating water, one that perseveres, no matter the season, the intensity of light, the length of the day. Plastic, yes, a choice. Or you might have tried Caulerpa taxifolia. It looks like an underwater fern, but it is a seaweed, native to the Indian Ocean. Many people love aquarium fish, and that includes biologists at the Oceanographic Museum of Monaco, who built habitats in large tanks with Caulerpa taxifolia a couple of decades ago and in the process released bits of the blades into drainage systems, which spilled them into the Mediterranean, where they regenerated and thrived, adapting to water colder than that of their native range. And then they began to spread. They grew much closer together than the original form, up to fourteen thousand blades in eleven square feet, and because of changes in the species’ behavior, phycologists began to refer to it as the aquarium strain. Swaths of the inshore Mediterranean waters quickly became sites of Caulerpa monocultures, outpacing native sea grasses and seaweeds.
Caulerpa taxifolia is an especially bright green, a bit neony, and it looks vaguely toxic, which in fact it is. It is eaten by very few Mediterranean sea animals, with the exception of the native salema porgy. Reputedly, when these fish feed on the seaweeds at their most poisonous (summer and early fall), the fish cause hallucinogenic reactions in people who cook and eat them.
However, those who work to keep the busy Mediterranean bays clean of sewage, farm runoff, and heavy metals, which accumulate in the waters around places where high numbers of people live and work, see a virtue in this form of Caulerpa. It is a volunteer seaweed for inshore phycoremediation. True, it outcompetes many natives, but it also rigorously takes in and retains in its tissues a range of pollutants, and water becomes clearer under its watch. It is too late to extricate Caulerpa from this beautiful, deeply historic body of water. The job has become an attempt to control its spread, through laws against possessing it, and cleanup where new patches begin.
In the United States, under the Noxious Weed Act, it is illegal to sell or transport this aquarium strain. California successfully eradicated a small colony of Caulerpa near San Diego by covering it with tarps, anchoring and sealing the perimeters of the tarps with sandbags, and pumping chlorine into the space beneath them. The chlorine killed everything it touched, but the tarps contained it, and the invasive seaweed was stopped.
There are over three hundred species of Sargassum, many of them a challenge to identify even for phycologists. Most grow in the tropics, anchored by a holdfast to a hard surface—shell, coral, or rock.
When these species detach from their holdfasts, through storm or age, and the currents and tides are just right to gather the loose blades together, turning them into floating mats, they can foul marinas, catch in boat propellers, and clog fishing nets. The British attempted to bulldoze, hand-cut, rake, trawl, and suction an invasive species of Sargassum that had formed mats along their coast, but the seaweed came back. When an herbicide was freely applied to a bay in Ireland that had been invaded, the Sargassum died, but almost everything else in the bay died with it.
And yet it is in the Caribbean and the Gulf of Mexico that a combination of Sargassum species has become much publicized and hotly debated. The species that are causing a problem start out growing from holdfasts in the Caribbean, in the Gulf of Mexico, and along the coast of Brazil where the Amazon empties into the Atlantic. They grow old or get pulled loose in the surf and wash ashore on West Indian islands, along the Yucatán, and in other resort areas. Piled high on beaches, rotting in the sun, and extending out for yards into the water, where they move like slush within the waves, the seaweeds meet and greet arriving tourists on whom these countries have come to depend.
Hawksbills are among the rarest sea turtles in the world, with only about twenty-two thousand nesting females in the Atlantic, Pacific, and Indian Oceans combined. Here in the western Atlantic, they nest on beaches in the Caribbean and along the Yucatán and the islands in the Gulf of Mexico. When those beaches are choked with seaweeds, the young cannot dig through the slippery mass after hatching, nor can they scramble over the tangle to the water.
Mats of floating Sargassum in the open water provide food and cover for hawksbills and capture heat needed by the very young turtles, but the pileup on beaches kills them.
What causes this plethora that turns a good thing bad? A great amount of attention—carefully scientific as well as carelessly hysterical—is being paid to the problem for a couple of reasons: the first is that people from waitresses to hotel owners to diving operators need to make a living in these places, and the second is that these same seaweed species have contributed enormously, creating a richness in the water fauna in the same way that healthy corals and mangroves and sea grass beds do.
All river water eventually pours into the oceans, and the Amazon discharges more water than any other river in the world. Runoff in the Amazon forests from cutting old-growth trees, contamination from the expansion of large agricultural plots to raise cattle and soy crops, and sewage from the new towns sprouting up on its banks, along with a prolonged rainy season that has always brought the forest to the river and thus to the sea, have altered what the Amazon carries from its inland drainage basin of 2,722,000 square miles.
As currents in the Atlantic carry that dark seam of river water north, the nitrogen and carbon in the overfed water affect the ocean. One of the first noticeable changes is increased seaweed growth. Add to this the pollution dumped into the Gulf of Mexico and the Caribbean, and the warming temperatures of climate change, and conditions are ripe for a sudden, overwhelming bloom.
A long, many-branched living Sargassum blade, anchored firmly by its holdfast close to shore and swaying in the water, can provide food and shelter for as many as three thousand lives, tiny lives to be sure, but necessary building blocks for larger ones. A blade like this can also host other seaweeds that attach themselves to it.
In a normal year, detached Sargassum either sinks to the bottom, turning the carbon it contains into food for creatures that prowl the ocean floor, or washes onto beaches in modest amounts and stabilizes the sands, building up the dunes and protecting the shore from storm damage. And when hungry migrating shorebirds arrive along these beaches in late summer and early fall, some amount of Sargassum at the tide line brings them the food they need. This is how it’s supposed to work.
Dr. Raul Ugarte works for the biggest seaweed harvesting, processing, and research company in the world: Acadian Seaplants Limited of Dartmouth, Nova Scotia. The company was founded in 1981 and handles thousands of tons of seaweed annually, making products with it or selling it to companies that add it to everything from beauty aids to plant-growth regulators. The company is also the inventor and producer of the high-end multicolored Chondrus crispus, or carrageenan, in its specialty aquaculture labs on the coast of Nova Scotia. Its products are exported to seventy countries worldwide. If there’s a Goliath in the seaweed business, this is it.
Ugarte is a native of Chile, but he has worked for Acadian Seaplants as a research scientist since 1995. Living in Atlantic Canada for many years, he commands a perfect English that is difficult to understand because it’s dressed in a heavy Chilean accent and inflection. I have watched at public meetings how native English speakers lean in and fix their eyes on him with a special intensity when he talks because they don’t want to lose the gist of his thought, and this linguistic opacity probably confers an added gravitas to what he has to say.
As the lead research scientist for his company, he is a smart, charming phycologist who knows as much about worldwide wild seaweed harvest as anyone anywhere. He is primarily an applied scientist, which means that his job is to make seaweeds available for things that people can use, whereas the goal of a basic scientist is to understand how something works. Actually, I believe Ugarte would say he’s a bit of both.
In the past ten years, Acadian Seaplants has extended its reach into Maine to harvest Ascophyllum nodosum with catalytic effect: it has forced this state, its coastal citizens, its inshore scientists, both applied and basic, its relatively modest seaweed companies, and the seaweed harvesters who sell to them, as well as bird biologists and fisheries biologists, to grapple with the issue of wild-cut seaweeds and what the future of the harvests means here. Without Acadian Seaplants, we might have gone on for some time in a relaxed, somewhat disorderly, but companionable way.
Now the Department of Marine Resources is prepared to make rules statewide for the harvest of Ascophyllum nodosum, the seaweed that is the most heavily cut, at over seventeen million wet pounds a year. It will become the first species of seaweed to be regulated. And one of the scientists at the table, helping to make this policy, is Raul Ugarte.
The company first initiated a harvest in Cobscook Bay in Maine, close to the Canadian border, and it outraged so many local citizens that a plan was written up by the department restricting the company’s reach into places around the bay deemed of special concern. Now, Acadian Seaplants moves slowly down the coast, getting closer to the center of Maine-owned businesses with their own cutting regimes. Some decidedly negative press has shadowed it here, as well as over on the northwest coast of Ireland. A few years ago, when Acadian Seaplants purchased a prominent Irish seaweed company that harvests Ascophyllum and that was partially government owned, and exacted from the government a ten-year moratorium on making the details of the purchase public, it had a run of bad press. For the time being, at least, this has caused the company to shut down requests for interviews, including my own. But Ugarte still appears at seaweed symposiums and conferences in this state, and although he can’t be interviewed, he gives a spirited overview of the values and standards of his company’s harvest and the cautions the company is willing to take to prevent depletion of a wild resource.
When I started as a contributing writer for Maine Times in the eighties, one of the people I interviewed was Dr. Steven Katona, now the director of the Ocean Health Index for Conservation International. Then he was the head of Allied Whale, a research group associated with College of the Atlantic in Bar Harbor.
This was a time when whale killing was still a routine practice for a number of countries around the world. It was done from factory ships, giant steel behemoths, and it involved shooting whales with mechanized harpoons armed with explosives that erupted after penetrating deep into the animal. The body, quickly secured with chains, was hoisted onto an industrial-scale flensing platform.
During the interview, Dr. Katona taught me a very simple concept. He said that if we had continued to hunt whales all over the oceans of the world using the hit-or-miss techniques that were described in Moby-Dick, published in 1851, whales would probably have remained abundant. We wouldn’t have made a dent in their populations—let alone a chasm.
What he was getting at was the same thing Paul Venno was talking about when I sat down with him, something so true that it’s often overlooked: the more we perfect our capacity to harvest wild nature, the closer we come to destroying what we seek. Today, Dr. Katona noted, there are more people, and they are inventing more machines that are too good at what they do.
I am reminded of the Aldo Leopold quote: “Our tools are better than we are, and grow better faster than we do. They suffice to crack the atom, to command the tides, but they do not suffice for the oldest task in human history, to live on a piece of land without spoiling it.”
The question is whether Ascophyllum nodosum, the most intensely cut species here in Maine and along the eastern Atlantic, is being subjected to the same sort of mechanized destruction. The answer is somewhat unclear.
Ascophyllum nodosum, growing from Europe’s northwestern coast down to Portugal and from Greenland to the coast of North America down to New Jersey, covers our high intertidal zone along this rocky coast, where it clings with its holdfasts and swings its long blades in the tides and currents. If you travel the shores of the Gulf of Maine in the state of Maine, you know it, because in every sheltered and mildly turbulent cove or bay it presides as a thick, protective fringe of life. But every bay and cove is slightly different. Each offers nutrients and anchoring sites for seaweeds that are unique to themselves, and because of these distinctions it is impossible to say with accuracy just how long it will take a harvested seaweed bed to recover: sometimes Ascophyllum grows back very quickly, and sometimes it takes years.
Ascophyllum is processed for alginates, added to the food of farm animals, and used in some health foods for human nutrition, but it is as a soil amendment and conditioner that it shows an almost miraculous promise. According to the research from sources compiled by Michael D. Guiry, a phycologist and former director of the Ryan Institute in Ireland, Ascophyllum amendments improve soil structure and prevent erosion. Seaweed extracts, made primarily from Ascophyllum and used in farming and nursery projects, increase the resistance of plants to frost and increase their uptake of organic matter from the soil. They also improve a plant’s resistance to stress, reduce the incidence of fungal and insect attack, facilitate seed generation, and protect plants from damage when used directly on roots as a dip in transplanting.
New Hampshire currently permits no commercial rockweed harvest, and Massachusetts Division of Marine Fisheries doesn’t regulate a commercial rockweed harvest because it assumes there is none. Ascophyllum beds and the beds of Fucus species are left alone in these states for now, except for the occasional citizen gathering modest amounts for garden compost or a lobster bake. In Nova Scotia and New Brunswick, Canada, there are robust commercial harvests of wild rockweeds, as there are in Maine.
Where these harvests occur, you can approach Ascophyllum from the water or the shore, and only two things restrict your take: the tools you use and the regulations you follow. A third might be how you understand your relationship to the place where you work and live.
In Maine there are three means of cutting. The simplest is with a knife or machete. It is the low-tech, small-harvest option. The advantage is that the harvester can see exactly how high up the Ascophyllum blade he or she cuts. The disadvantage is that you are stepping on beds of the seaweed as you cut. Maine state regulations now require a sixteen-inch leaving, which gives this seaweed, living for as long as twenty years (a few phycologists say much longer, even suggesting that a holdfast might persist for up to a century), a chance to come back.
The second method of harvesting is with a cutter rake, and this is what Acadian Seaplants gives to the workers it hires. It provides each of them with a flat-bottomed boat and a rake with a knifelike blade soldered behind the tines and a built-in dam on either side to prevent too close a cut. The harvester plunges the rake directly down into the seaweed bed and heaves it upward with both hands, slicing the seaweed fronds, then swings the rake over the gunwale and into the boat, shakes the seaweed out into the hull, and plunges the rake back into the water again.
It does a job on the rotator cuffs, but it can get pretty close to a leave limit of sixteen inches as the boat drifts along the shore, unless the harvester attaches a rope to the rake, throws it out into the water, and yanks it, ripping the seaweeds and their holdfasts off the rocks. People standing on land watching some of the harvesters work the tide have documented with photographs this rope maneuver. It’s not how they were trained, but it’s faster, easier, and kinder to the rotator cuffs.
The third method, used primarily in Midcoast Maine, is the mechanical harvester: a flat-bottomed boat with a rotary cutting head and a suction hose that pulls water over the cut weed and spews it into netted bags. This manner of harvesting has undergone some improvement over the years; mechanical harvesters now use biodegradable fluids, in case of a malfunction, and built-in guards have been installed to minimize bycatch. The bagged seaweed is floated on the water until the tide begins to change, when the harvester picks them up, tows them behind the boat, and heads toward the unloading dock and the boom cranes and the trucks.
A good harvester, with rake or mechanized boat, can cut five tons of Ascophyllum a day and can earn $1,500 a week. More rapacious harvesting methods were tried years ago in Nova Scotia and are now outlawed, and in Europe machines are sometimes used to clear-cut sections of seaweed beds that require long fallow periods of regrowth and recovery.
There have been a handful of small but thriving private Ascophyllum businesses on this coast for almost forty years. With the arrival of Acadian Seaplants and its potential to overshadow them, they have organized themselves into a group of seaweed business owners, harvesters, and scientists—including a member recently retired from Acadian Seaplants—to form the Maine Seaweed Council. They have given themselves the job of educating the public about what they do and advocating for the protection of their resource and their investment.
This oversight of their own interests, along with public outreach and education, may help prevent rogue cutting and the introduction of machines that are more rapaciously high tech than the mechanical harvester is today, because rogue cutting and overharvesting practices eventually hurt them, too.