Clam or Tree?

Three of us were spending the afternoon stomping around a seaweed bed on the coast of Maine. It was a classic landscape— rocky granite outcrops and conifers above us, cobbly beach draped in ropy seaweed at our feet— and a pretty gorgeous place to be doing research, in spite of the why-am-I-forever-surprised-that-it’s-still-cold weather of Maine in March.

“Okay,” my colleague asked me, kicking at some of the seaweed. “So what do you think? Is this more like a clam, or more like a tree?”
I know. It’s an absurd question. But it’s also a serious one,and its answer could have significant impacts for the economy and ecology of coastal Maine— not to mention our interpretations of codes on public usage, private ownership, and general management and stewardship of marine resources.

But I’m getting ahead of myself. Let’s get back to that idyllic, iconic, rocky coast of Maine.

The seaweed we were looking at was rockweed, or Ascophyllum nodosum.

A gorgeous bed of Ascophyllum nodosum. (Images are author’s own.)

Asco, as it’s been nicknamed, is a brown alga that grows in dense, beautiful mats along the rocky coast of Maine (as well as most of the Atlantic coast between 40 degrees north and the Arctic Circle). It thrives in the intertidal, floating vertically in the water column at high tide and matting over exposed rocks at low tide. Rockweed mats buffer the intense light and temperature conditions of the intertidal at low tide and offer a 3-D structure at high tide, making it an important habitat-forming species for a bevy of invertebrate inhabitants. It supports everything from the unobtrusive isopod to the charismatic lobster, as well as fish and seabirds. Ecologically, it’s a pretty important intertidal player.

Rockweed is increasingly important to humans, as well. It has likely been harvested ever since the glaciers receded and the coast became habitable for humans, approximately 12,000 years ago. In recorded history, early colonists and their descendants have used rockweed for fertilizer and as livestock feed. More recently, rockweed use has developed into a commercial fishery with a global market.

Colonists and their predecessors used rockweed straight-up, but today, there’s not much demand for straight rockweed. Instead, the commercial use relies on post-harvest processing, in which the plant is refined into fertilizers and nutritional supplements for humans and livestock. As the demand for rockweed products has increased, so has rockweed harvest, which has prompted more new ways to process and use rockweed, which has increased harvest, and so on.

In 2003, a total of 3.3 million pounds of rockweed were harvested in Maine. By 2012, this number had risen to 14.6 million pounds. That’s an astonishingly fast increase in harvest.

This rise in harvest has been accompanied by the beginnings of state-mandated regulation. Briefly: rockweed harvesters and buyers are required to have permits to take more than 50 pounds of seaweed for commercial purposes, and face fines if they harvest beyond certain take limits. Cutting limits prevent harvesters from leaving fewer than 16 inches of the rockweed plant, from holdfast to tips, remaining after they harvest. In certain parts of the state, harvesters are required to submit a harvest plan that includes rockweed biomass assessments conducted at least every 3 years.

Still, these regulations haven’t been strict enough to assuage concerns that rockweed is being overharvested. Maine has a history of overfishing (see: collapse of cod, collapse of sea cucumbers, collapse of lobster), so these fears are well-founded. Besides that, there’s a relative lack of information about rockweed’s response to harvest. How does the alga manage the damage caused by cutting? How quickly does it regrow? Does a 16-inch limit maintain enough of a rockweed canopy to support ecological functions? As rockweed harvest has increased, these concerns have become more pressing, and the need for more data has become clear. That’s why my research partners and I were out in the rockweed beds that day. Since March, we’ve been running a research project in attempts to respond to some of these unknowns. This project has us stomping around in the intertidal with temperature sensors and transect tapes, gathering data on tipping points of rockweed cover to help inform regulation limits. ( I should note: we’re not alone in this work, and we get to trade research methods and findings with a slew of interested people and researchers around Maine and Eastern Canada.)

Rockweed researchers at work.

The ecological roles and supportable limits are important questions— but there’s another element of uncertainty in this fishery. Because according to Maine law, no one knows who owns the rockweed. And that question, of course, is a major sticking point when it comes to sorting out who has the right to harvest it.

Which brings us back to the question: is rockweed more like a clam, or like a tree? Surprising though it is, the answer to that question might be key in shedding light on this debate.

This question is rooted in a history stretching back as long as humans have been deciding who gets rights of ownership and usage of natural resources. We’re talking about a pretty Western view of being in the world, here (and there’s an important place for the very fair argument that no one truly owns the rockweed, though I won’t tackle that here), so it helps to look at it through several particularly influential Western codes. In Justinian codes from 535 CE, “the shores of the sea” are described as being a common resource for all mankind, and allowed to be used by any member of the public. Or take the Magna Carta— when the British aristocracy forced King John to limit his powers in the woods of Runnymede in 1215, they included a prohibition that kept the king from granting exclusive (private) rights to intertidal lands. Essentially, that kept the strip of land between high tide and low a publicly accessible resource. Centuries later, as they crafted a new form of government, American colonists held on to this idea— they decided that the intertidal should belong to the state “in trust for the benefit of the public”.

Except, that is, for the colonists of Maine and Massachusetts. Here, the Colonial Ordinance of 1641-47 placed ownership of that land in the hands of private upland landowners. In other words, if you own a plot of land along the coast, you have private ownership rights all the way down to the low tide mark. There’s a trade involved here, though— for the privilege of privately owning that land, it has to remain publicly accessible for three uses: fishing, fowling, and navigation. The specific boundaries of those categories have been hammered out on a case-by-case basis by the Maine courts ever since. The result is a curious patchwork of allowances: you can’t sunbathe, but you can hunt duck; you can’t collect dead shells, but you can moor your kayak; you can’t stroll, but you can cross land purposefully if your goal is to reach the ocean. Unsurprisingly, these rules have sparked a fair amount of argument from landowners and public users alike.

The “fishing” component of this ordinance has prompted perhaps the most debate. Certain activities are relatively straightforward— casting a line for bluefish using a rod definitely qualifies as fishing, and is allowed under the ordinance. Other activities are a bit harder to define. Take clamming, for example. A clam is not a fish, taxonomically speaking. It’s an invertebrate, a mollusk. However, in the eyes of Maine law, if it acts like a fish (mobile, living in the intertidal, getting its resources from the sea rather than the sediment, harvested as seafood), it’s managed like a fish. That means that, in Maine law, clams (along with not-technically-fish intertidal critters like mussels and marine worms) are public trust resources that are held by the state for use of the public. To better understand this, take the counter-example of a tree (and, okay, not so many trees grow in the intertidal but bear with me). A tree rooted in the soil is seen as an extension of the land in a way that a mobile fish is not. As an extension of that private land, it’s not part of the public trust, and cannot be harvested without landowner permission.

Examining a rockweed holdfast.

So you’ve got your trees, and your clams. But then there’s rockweed. It grows in this ribbon of privately-owned intertidal land— but does it fall under the fishing, fowling, and navigation provision? Does it count as a tree-like extension of private land, or a clam-like member of the public trust of fishing?

If it falls into the category of fishing, then its harvest is explicitly allowed on intertidal lands even if the upland land is privately owned. But if the case for rockweed-as-fish doesn’t stand, private landowners will be in the position of deciding whether or not rockweed take can occur in the intertidal areas of the land they own.

So this slightly absurd question actually has serious implications. And it’s all coming to a head now. In 2016, two private landowners from Roque Isle, Maine filed a lawsuit against the seaweed harvesting company, Acadia Seaplants Ltd. For years, Acadia Seaplants Ltd harvesters had been gathering rockweed from private land, and the landowners argued that this was akin to stealing their private property. The case was in the courts for months. Outside of the courts, landowners, seaweed harvesters, fishery regulators, lawmakers, and scientists alike found themselves debating the ownership of rockweed, hashing and rehashing the clam-or-tree question.

This March, the Washington County Superior Court came to a decision. Its ruling? Drumroll, please: rockweed is more like a tree. Or, more exactly, they said: “Harvesting a terrestrial plant is not more a fishing activity, such as worming, digging for mussels, trapping lobsters or dropping a line for fish clearly are, than is harvesting a tree the same as hunting or trapping wildlife. Rockweed is a terrestrial plant. The harvesting of rockweed cannot be said to be a form of fishing, fowling, or navigating.” In addition to the fishing, fowling, and navigation point, the court went on to discuss how rockweed fits into the history of ownership and usage cases in Maine law. From a variety of angles, they concluded that rockweed really does fall under private ownership.

Of course that’s not the end of the story. Acadia Seaplants Ltd. plans to appeal the case, so the Maine Supreme Court will be tackling the question soon. The debate on whether rockweed is more like a clam or more like a tree is by no means over, and is still open for new interpretations and decisions.

Scoping out a rockweed bed.

But if this ruling stands, it’s going to have significant impacts on the future of rockweed harvest. Here on the coast, muck boots in the rockweed bed, we’ll be watching where it goes.

2 thoughts on “Clam or Tree?

  1. Very nice post Ellie on a very important topic. I confess that I am super skeptical of the folks who say “we have always harvested rockweed” as justification for a large multi-national corporation to come in & take & take for a “global market”. Furthermore, when i hear arguments for this as a local sustainable industry I can’t help thinking about how well we have conserved the fisheries of the Gulf of Maine. As you point out, Rockweed is a critical habitat for a broad range of organisms. Clear-cutting it along large stretches of the coast is unlikely to do those organisms any favors. I will be interested in hearing the results of your research.


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