April 28, 2021

Is Seaweed a Fish? U.S. Seaweed Fisheries and Climate Change

Ethan Prall

Seaweeds can have significant benefits for combating climate change, and the extent of seaweed industry regulation in the United States will be a key issue in the coming years. According to the Intergovernmental Panel on Climate Change (IPCC), society needs many different climate mitigation technologies to achieve “net zero emissions” in time to prevent climate disaster. See, e.g., IPCC, Global Warming of 1.5°C 17 (Valérie Masson-Delmotte et al. eds., 2019). Seaweed harvest promises to be a significant climate mitigation tool because seaweeds absorb vast amounts of carbon while supplying foods and renewable fuels.

Still, overexploitation of seaweeds can create problems for ocean ecosystems that must be managed. Seaweed harvest in U.S. federal waters is currently regulated, but the appropriate extent of such regulation is debatable. Commenters have argued that for ocean ecosystems to adapt to climate change, U.S. fisheries regulations must be modified. See Don Gourlie, Reeling in Uncertainty: Adapting Marine Fisheries Management to Cope with Climate Effects on Ocean Ecosystems, 47 Env’t L. 179, 222–24 (2017). The corollary is equally true: In order to help mitigate climate change in the first instance, the U.S. fisheries regime also must change.

Until recently, U.S. seaweed harvest has been limited when compared to that of other countries. Where harvest has occurred in federal waters, seaweed has been regulated as a “fish” under the Magnuson-Stevens Fishery Conservation and Management Act (MSA or Act) because the Act defines “fish” to include marine plants. 16 U.S.C. § 1802(12). Nevertheless, regulating seaweeds as if they are fish is counterintuitive and raises the question whether the MSA’s current regulatory scheme could better facilitate development of the nascent seaweed industry. This article explains the benefits and potential risks of seaweed harvest in U.S. federal waters—primarily wild harvest rather than aquaculture—and analyzes mechanisms available under the MSA to limit regulatory burdens on the industry, at least absent evidence of overexploitation.

The Growing Seaweed Industry and Climate Change

Seaweed has been harvested for centuries in Asia and elsewhere for food, but little has been known about its remarkable carbon properties until recently. See Jang K. Kim, Michael Stekoll & Charles Yarish, Opportunities, Challenges and Future Directions of Open-Water Seaweed Aquaculture in the United States, 58 Phycologia 445, 446–47 (2019). Interest in seaweeds is growing in the United States, which possesses the largest offshore ocean area of any country in the world. Significantly, wild harvest of seaweed often supplies the seed stocks used in seaweed aquaculture. See, e.g., Jang K. Kim et al., Seaweed Aquaculture: Cultivation Technologies, Challenges and Its Ecosystem Services, 32 Algae 1, 3 (2017). “Currently, seaweed aquaculture is one of the fastest growing maritime industries in the coastal waters of New England,” and seaweeds have been harvested in Alaska, California, and other states as well. Kim, Stekoll & Yarish, supra, at 446–47, 451. This expansion reflects a broader global trend, in which seaweeds now compose 27% of all marine aquaculture. Carlos M. Duarte et al., Can Seaweed Farming Play a Role in Climate Change Mitigation and Adaptation?, Frontiers Marine Sci., Apr. 12, 2017, at 1.

Harvested seaweeds are used in foods, including kelp noodles, salads, and slaws, and in renewable biofuel applications. In 2018, the U.S. Department of Energy began financing proposals to develop offshore seaweed harvest technologies, primarily for renewable biofuels production. Advanced Rsch. Projects Agency—Energy (ARPA-E), U.S. Dep’t of Energy, Macroalgae Research Inspiring Novel Energy Resources (MARINER) Program Overview 2 (Sept. 19, 2017). Many of these proposals for seaweed harvest are intended for the exclusive economic zone (EEZ), the zone of waters extending from the boundary of state waters (generally the first three miles from shore) to 200 miles offshore, and some involve wild harvest.

Scientific studies of seaweeds’ climate mitigation potential are at least partially driving the increased interest in seaweeds. Seaweeds absorb substantial amounts of carbon, die, and then naturally migrate out to sea, where they drift down to the deep seabed. Sylvia Hurlimann, How Kelp Naturally Combats Global Climate Change, Sci. in the News, July 4, 2019. Harvested seaweeds also furnish the raw ingredients for biofuels that can replace carbon-intensive fuels, and recent studies indicate that seaweeds can be used in cattle diets to substantially reduce emissions of methane, a powerful greenhouse gas. Duarte, supra, at 2–4. One study estimated that “macro-algae [seaweed] forests covering 9% of the world’s ocean surface . . . could produce sufficient biomethane [fuel] to replace all of today’s needs in fossil fuel energy, while removing 53 billion tons of CO2 per year from the atmosphere, restoring pre-industrial levels.” Antoine de Ramon N‘Yeurt et al., Negative Carbon via Ocean Afforestation, 90 Process Safety & Env’t Prot. 467, 467 (2012). In fact, seaweeds “are better than terrestrial plants at fixing carbon dioxide, and produce a plant that is nearly 100% harvestable,” unlike many terrestrial crops. ARPA-E, supra, at 5. Scholars also have concluded that seaweeds can generate very substantial carbon offsets through “blue carbon” offset markets. Halley E. Froehlich et al., Blue Growth Potential to Mitigate Climate Change Through Seaweed Offsetting, 29 Current Biology 3087, 3089 (2019). Finally, seaweed communities can produce direct ecosystem benefits, such as by increasing biodiversity and reducing ocean acidification.

Nevertheless, seaweed harvest raises some environmental concerns. Wild seaweeds often provide important habitat for developing fish, and other species of marine animals (such as threatened sea turtles) use seaweed to grow and mature. See, e.g., Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Pelagic Sargassum Habitat of the South Atlantic Region, 68 Fed. Reg. 32,450, 32,452 (May 30, 2003). Overharvesting of wild seaweeds can potentially affect these animals. Seaweed aquaculture also can create ecological problems, including impacts to protected species and water pollution. Read Porter & Rebecca Kihslinger, Federal Environmental Permitting of Offshore Aquaculture: Coverage and Challenges, 45 Env’t L. Rep. News & Analysis 10,875, 10,876 (2015).

Several characteristics distinguish wild seaweed harvest from traditional fishing, in addition to the object of harvest. First, and most important, the climate-mitigating potential of seaweeds means that the growth of the seaweed industry—like other negative carbon industries—has special immediacy. The IPCC recently concluded that civilization has less than a decade to make dramatic changes to ward off the worst effects of climate change. Further work remains to be done to quantify the exact extent of wild seaweed harvest’s carbon benefits. But wild harvest can provide climate change mitigation tools even when harvested seaweed is no longer exported to the deep seabed because that seaweed can be used in biofuels, in methane-reduction applications, or as seed stock for aquaculture applications that themselves have carbon benefits. Duarte, supra, at 2–4.

Other practical differences between wild seaweed harvest and traditional commercial fishing are notable. In particular, commercial seaweed harvesters employ a variety of methods in wild harvest. Perhaps the least intrusive techniques entail extracting seaweed fronds by hand from boats and collecting seaweed detritus from beaches. Other harvest techniques are more similar to commercial fishing and include the mechanical use of “seaweed trawlers” to scoop seaweed from the water. See Michéal Mac Monagail et al., Sustainable Harvesting of Wild Seaweed Resources, 52 Eur. J. Phycology 371, 373–77 (2017).

The MSA Framework

Calibrating federal seaweed regulation under the MSA to facilitate its climate benefits while preventing its harms is thus crucial. Regulating wild seaweed harvest just like commercial fishing can seriously constrain innovative attempts to develop low-impact commercial harvest and associated carbon solutions.

In 1976, Congress enacted the MSA to guard against overfishing and to manage fish in the nation’s EEZ, finding that the economies of “[m]any coastal areas . . . have been badly damaged by the overfishing of fishery resources.” 16 U.S.C. § 1801(a)(2). Although Congress at the time was thinking about overfishing in traditional fisheries, 45 years later new marine developments are testing the MSA’s legal scope—including the growing interest in seaweeds.

The MSA ushered in a coordinated and expansive approach to managing commercial fishing. The Act established eight Regional Fishery Management Councils (Councils), each tasked to prepare Fishery Management Plans (FMPs) for fished species in the region under its control. Id. § 1852(h)(1). The National Marine Fisheries Service (NMFS) regulates fisheries under the MSA and reviews the Councils’ determinations. The MSA governs only activities that are directed at “fish,” which it defines expansively as “finfish, mollusks, crustaceans, and all other forms of marine animal and plant life other than marine mammals and birds.” Id. § 1802(12) (emphasis added). The Act thus subjects marine “plants” to fishery regulation.

The MSA defines “fishing,” in turn, to mean the actual or attempted “catching, taking, or harvesting of fish” or activities that can be expected to result in such harvest. Id. § 1802(16). Recent case law, however, indicates that these activities do not include aquaculture; specifically, the U.S. Court of Appeals for the Fifth Circuit held in August 2020 that NMFS and the Councils do not have authority to regulate aquaculture under the MSA. Gulf Fishermens Ass’n v. Nat’l Marine Fisheries Serv., 968 F.3d 454, 458 (5th Cir. 2020). This article thus focuses on regulation of wild harvest rather than seaweed aquaculture.

Fishing under the MSA typically must take place in a “listed” fishery, using “listed” approved gear, and subject to an FMP issued for the fish species in question. NMFS’s regulations contain an exhaustive list of fisheries for each Council. 50 C.F.R. § 600.725(v). While the MSA does not outright ban fishing in unlisted fisheries, it does state that “no person or vessel may employ fishing gear or engage in a fishery not included on such list without giving 90 days advance written notice” to the relevant Council. 16 U.S.C. § 1855(a)(3). NMFS’s implementing regulations likewise prohibit fishing outside a listed fishery, although there is a limited exception for “an individual fisherman,” who may fish in an unlisted fishery or with unlisted gear 90 days after notifying the relevant Council, absent regulatory action to the contrary. 50 C.F.R. § 600.725(v). This notice requirement provides NMFS with time to issue temporary emergency regulations for the new fishery if needed. NMFS’s regulations also exempt certain noncommercial fishing from the fishing prohibition, including scientific research, recreational angling, and certain exempted fishing that requires annual permits. Id. § 600.745.

NMFS and the Councils have substantial discretion in determining when to issue an FMP for a listed fishery. See, e.g., Anglers Conservation Network v. Pritzker, 70 F. Supp. 3d 427, 441 (D.D.C. 2014). The MSA provides that the relevant Council “shall” propose an FMP for NMFS’s approval if the fishery requires “conservation and management.” 16 U.S.C. § 1852(h). Importantly, however, NMFS has explained that “[n]ot every fishery requires Federal management.” 50 C.F.R. § 600.305(c). Instead, an FMP is required only for stocks “that are predominately caught in Federal waters and are overfished or subject to overfishing, or likely to become overfished or subject to overfishing,” although Councils “may” issue FMPs for other reasons. Id. If a Council does not propose a required FMP, NMFS may issue an FMP itself. 16 U.S.C. § 1854.

An FMP must comply with the MSA’s National Standards, the first of which is the prevention of overfishing. 16 U.S.C. § 1851(a)(1). Additionally, each FMP must, among other things, specify conservation and management measures; assess the condition and yield of the fishery; describe essential fish habitat; specify criteria for determining overfishing; describe commercial, recreational, and charter fishing sectors that participate in the fishery; and establish annual catch limits. Id. § 1853(a).

Finally, the MSA requires NMFS to publish a list of approved fishing gear that may be used in listed fisheries. If a fisherman intends to fish in a new fishery or to use new gear, he or she must first comply with the new gear approval process, which requires the fisherman to notify the relevant Council 90 days before using the gear. 50 C.F.R. § 600.747(b)(3). Significantly, the Council does not have a deadline by which to decide whether to approve the gear. Thus, the FMP issuance process and approved gear process together can substantially delay harvest in new fisheries.

This regulatory framework poses at least three serious challenges for wild seaweed harvest in the EEZ: (1) the application of the MSA to plant fisheries, (2) the prohibition on unlisted fishing, and (3) the FMP issuance and gear approval process. The first challenge probably requires Congress to act, but NMFS and the Councils could address the final two challenges either by amending key regulations or by exercising their existing discretion over fisheries.

Are Seaweeds Plants and Thus “Fish” Under the MSA?

The first challenge to regulating seaweed harvest arises from the application of the MSA to marine plants. NMFS has concluded that seaweeds are plants for purposes of the MSA, but to date, it has issued only one FMP for a “plant fishery”—the South Atlantic Council’s FMP for pelagic Sargassum, a brown surface seaweed. Sargassum is also regulated in the Mid-Atlantic as a “non-FMP” fishery, which means that NMFS has listed the fishery without issuing an FMP. 50 C.F.R. § 600.725(v). NMFS’s regulations and guidance do not fully explain the process or rationale for listing non-FMP fisheries.

Historically, one firm on the U.S. East Coast, Aqua 10 Laboratory, harvested Sargassum in the EEZ. According to the South Atlantic Council, between 1976 and 1997, Aqua 10 harvested Sargassum in the wild off the coast of North Carolina and used it to produce fertilizers and animal feeds. NMFS valued the company’s annual harvest, averaging 14,333 pounds per year, at approximately $43,000. Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Pelagic Sargassum Habitat of the South Atlantic Region, 68 Fed. Reg. 57,375, 57,377 (Oct. 3, 2003).

The South Atlantic Council and NMFS decided in 2003 to regulate Sargassum as a marine plant. In the FMP, the Council explicitly observed that it was taking a “risk-averse” approach in light of limited understanding of Sargassum at the time. S. Atl. Fishery Mgmt. Council, Fishery Management Plan for Pelagic Sargassum Habitat of the South Atlantic Region 1 (2002). NMFS expressed concern about the importance of Sargassum as habitat for many fish species, as well as threatened sea turtles. The Sargassum FMP thus drastically limits the annual total allowable catch in the South Atlantic to only 5,000 pounds per year, to be harvested during only four months of the year within specific geographic areas. Essentially, the FMP precluded any commercial Sargassum fishery. “The Council concluded that severe limitation on harvest is likely to increase the productivity of marine life in the ecosystem,” noting also that “there was overwhelming public support for a measure to prohibit the directed harvest of sargassum.” 68 Fed. Reg. at 57,377.

Although the Sargassum FMP has not been challenged, NMFS’s decision to regulate Sargassum under the MSA is debatable. Seaweeds are not scientifically classified as members of the kingdom of plants; instead, they are a type of “macroalgae” that biologists classify into the kingdom of “chromists.” Because the Act encourages Councils to use the best available scientific knowledge when establishing FMPs, there is a serious argument that seaweeds are not plants and thus are not within the definition of “fish” in the MSA. However, in the absence of management under the MSA, seaweed harvest in federal waters would be largely unregulated, which could have detrimental effects on ocean ecosystems, including fisheries. Additionally, NMFS has already exercised jurisdiction over Sargassum. For these reasons, absent other legislation, NMFS probably will continue to assert some regulatory authority over wild seaweed harvest.

Can NMFS Modify Its Regulations to Better Accommodate Seaweed Harvest?

The second major challenge for seaweed harvest is NMFS’s regulatory prohibition on commercial fishing outside of a listed fishery, typically governed by an FMP. NMFS’s noncommercial exemptions from the prohibition probably would not apply to commercial seaweed harvest. However, as noted, an exception to the prohibition states that an “individual fisherman” may fish in an unlisted fishery 90 days after notifying the relevant Council, absent regulatory action to the contrary. 50 C.F.R. § 600.725(v). It is unclear how NMFS would apply this exception in practice, but, regardless, the exception is too narrow to apply to most commercial seaweed harvesters.

There is, however, a simple solution. Instead of limiting the exception to an “individual fisherman,” NMFS could amend and broaden that language to “any person.” This change would allow commercial harvesters—not just individuals—to harvest in the EEZ after waiting 90 days, while also allowing NMFS time to issue regulations that seek to limit seaweed harvest. In fact, this change would more closely align with the MSA’s own text, which provides that “no person or vessel may employ fishing gear or engage in a fishery not included on such list without giving 90 days advance written notice” to the relevant Council. 16 U.S.C. § 1855(a)(3) (emphasis added). NMFS’s reasons for narrowing the MSA’s exception from any “person” to an “individual fisherman” are not clear, and the suggested amendment would preserve the agency’s ability to monitor and seek to limit seaweed harvest if warranted. Without this amendment, seaweed harvest in any region of the EEZ could require listing of the seaweed fishery, the establishment of a new FMP, and approved gear regulations, all of which could significantly delay this growing industry—and the potential climate change mitigation benefits it offers.

How Can NMFS and the Councils Exercise Their Discretion to Promote Seaweed Harvest?

The FMP process is the final challenge that the MSA’s current framework poses to emerging seaweed industries. Every FMP must contain a number of conditions, requiring a lengthy engagement among the relevant Council, NMFS, and industry participants. However, as noted, not every fishery in federal waters requires an FMP. Rather, a regional Council (or NMFS) prepares an FMP only for fisheries that require “conservation and management.” The MSA defines “conservation and management” to mean rules and methods “required to rebuild, restore, or maintain” the fishery or environment, suggesting that conservation and management apply primarily to stocks that are in danger of overfishing or the harvest of which could damage the marine environment. See 16 U.S.C. § 1802(5). In fact, NMFS itself instructs that an FMP is required only for stocks that “are overfished or subject to overfishing,” although Councils may issue FMPs for other reasons. 50 C.F.R. § 600.305(c)(1). Commenters and courts also have recognized the centrality of preventing overfishing to the MSA’s regime. See, e.g., Gourlie, supra, at 224 & n.78.

Overharvest of wild seaweeds is not currently a significant concern in the United States, although it has been at times in other countries. Cf. Monagail et al., supra, at 375–76. Wild harvest globally accounts for a mere 4% of the world’s seaweed production, and there are few indications that wild seaweeds are likely to become overfished in the U.S. EEZ. Moreover, sustainable harvest techniques are available, including hand harvest from boats. Of course, NMFS should be vigilant in monitoring to prevent overharvest. But given seaweed’s significant benefits, the burden should not be on the industry to demonstrate that its harvest is allowed. The MSA’s own text and NMFS regulations show that the inverse is true: The statutory burden is on the Councils and NMFS to show that an FMP is warranted because of environmental risks, particularly overfishing.

In the absence of substantial environmental risks, NMFS thus should exercise its discretion to allow the wild seaweed harvest industry to develop without initially requiring FMPs. Contrary to the agency’s position in the South Atlantic Pelagic Sargassum FMP, the industry should not be effectively precluded from the outset. Instead, NMFS should allow wild harvest to take place, in tandem with scientific study and monitoring, in order to facilitate seaweed’s climate mitigation and other benefits. NMFS and the relevant Council(s) could list seaweeds in “non-FMP” fisheries, as with Sargassum in the Mid-Atlantic. Such listing would avoid the full FMP issuance process while allowing commercial seaweed harvest to begin, even if NMFS did not expand its exception to the fishing prohibition to include commercial fishermen.

Next Steps for Federal Seaweed Regulation

Wild seaweed harvest, together with seaweed aquaculture, may prove to be an important component of a “blue carbon” strategy to mitigate climate change, while providing foods and ecosystem benefits. The MSA’s current regulatory scheme and NMFS’s past opposition to seaweed harvest threaten to stop the wild harvest industry in federal waters before it begins. However, even if the MSA applies to seaweed, NMFS and the regional Councils can eliminate the current regulatory barriers to this new industry through their existing discretion over fisheries management. NMFS can modify its regulations to allow commercial harvest by “any person” in new fisheries after 90 days’ notice, absent contrary agency action. Moreover, the regional Councils and NMFS can exercise their discretion to allow wild harvest to proceed initially without FMPs, subject to the regulators’ ongoing review. These relatively small changes to the MSA’s regime and past regulatory approaches to seaweeds would allow fisheries regulators to enhance and facilitate a negative carbon seaweed industry in federal waters.


Ethan Prall

Mr. Prall is an associate at Latham & Watkins LLP in Washington, D.C., and may be reached at ethan.prall@lw.com.