Development of the Sargassum Industry in the Caribbean: The Wrong Kind of Abundance

Each year, on Caribbean shores, a resource arrives in growing quantities and with no extraction cost. It requires no exploration, drilling, or cultivation. It is called sargassum, a type of seaweed that forms in large mats in the ocean and accumulates on shorelines. It has not become an industry. In any other sector, a free and abundant raw material would generate investment, competition, and scale. With sargassum, the opposite is happening: its abundance is not driving growth in the sector that is supposed to take advantage of it.

The evidence shows that the problem with sargassum is not a lack of resources, but rather the absence of public goods: reliable information, quality standards, regulatory frameworks, and regional coordination. In this regard, it is essential for the countries in this region to work hand in hand to build the enabling conditions that no private actor can provide on its own. Understanding this distinction is key to transforming sargassum into a real opportunity for a functioning market.
 

In July 2025, satellites confirmed an Atlantic sargassum bloom of 38 million metric tons, 58% higher than the previous record. That figure is repeated in every forum, every proposal, every headline. But alongside it coexist many other figures that go almost unnoticed. Hotels in the Riviera Maya alone spend tens of millions of dollars each year on private beach containment. An econometric study by the IDB found that the presence of sargassum reduces gross local product in affected coastal areas by 11.6%, with effects that persist for up to twelve months. In Martinique and Guadeloupe, hospitals recorded more than 11,000 cases of acute exposure to toxic gases in a single year. And the list goes on.

Sargassum keeps arriving, and the costs of dealing with it keep accumulating; the utilization industry, however, does not grow at the same pace. The gap reflects a measurement error. What matters for the industry is not the total volume that reaches the coast, but the fraction that a facility can effectively feed into its machinery on a given day and convert into a marketable product. That fraction, and not the headline tonnage of biomass washed ashore, is what guides investment decisions.

Between what the satellite sees and what the factory can use, four simultaneous constraints are at work, each worsening the impact of the others.

• The first is time. The quality of sargassum begins to deteriorate the moment it reaches shore. Under tropical heat, anaerobic decomposition starts in less than 48 hours, releasing toxic gases before collection teams can even mobilize. The real operational window is only 48 to 72 hours before the material falls below what most industrial applications require.
• The second is contamination. Caribbean sargassum contains arsenic levels that, in 86% of analyzed samples, exceed international regulatory limits. There are laboratory techniques that can reduce arsenic by more than 97%, but none have worked at an industrial scale. The distance between a laboratory batch and a production line is where every promising result has dissolved.
• The third is material variability. The Atlantic belt contains at least three biological varieties of sargassum with very different chemical and energy properties. Their proportion changes from month to month and cannot be inferred from a satellite. What a plant receives today is a different material from what it received last quarter.
• The fourth is logistical congestion. Large arrival events, that generate the greatest political urgency, are precisely the ones that overwhelm collection capacity. What appears most promising from a satellite perspective is often what destroys usable volume most efficiently on the ground.

The net result: satellites capture images of millions of tons. The factory runs on a small, volatile, and unpredictable fraction of that. This gap is not a technical detail, it helps explain why pilot projects aimed at fostering industry development have not been able to scale up in recent years.

Here emerges the consequence that contradicts the dominant intuition: an investor does not size a plant anticipating a "perfect year". They size it for a "difficult year" in which the business must still survive financially, because fixed costs (loans, salaries, maintenance, insurance) do not stop when sargassum stops arriving in usable condition. When supply is volatile, building big is not ambition: it is exposure to the risk of having an idle plant that consumes capital without generating revenue.

Investment theory under uncertainty formalizes this mechanism, and Caribbean evidence confirms it: when supply volatility is sufficiently high, an increase in that volatility reduces the optimal size of the facility. The proliferation of pilot projects across the Caribbean reflects rational firms preserving their option to exit, remaining small enough to stop without catastrophic loss. Under current conditions, the pilot is not a stepping stone to an industrial plant—it is the sector’s equilibrium outcome.

Global alginate buyers prefer to pay for sargassum cultivated in Southeast Asia rather than use the material that washes up for free on Caribbean shores. When the raw material is free and buyers choose to pay for another that is not, the obstacle is not price—it is quality, consistency, and predictability.

These outcomes can't be explained by a lack of resources. Since 2018, bilateral and multilateral cooperation has mobilized significant funding for this issue. But the pattern has been to finance emergency cleanup and subsidies for processing plants, while little has been invested in what determines whether those plants can operate: the regional public goods, with information, quality standards, and regulatory frameworks, without which no sargassum market is viable. With greater clarity on the scale of the problem, financial resources can be used more efficiently.

The challenge of Caribbean sargassum is, at its core, an opportunity to leverage public goods rather than a raw materials problem. Public goods can be advanced by building shared infrastructure that no private actor has the incentive or capacity to develop on its own. Shifting the focus toward a comprehensive and shared vision that enables the private sector to operate is key for this industry to gain traction.

Subsidizing a processing plant means financing a private good: it benefits the recipient. Building the infrastructure that allows an entire market to function means providing a public good: it benefits everyone simultaneously, and precisely for that reason, no private actor finances it alone. Each waits for someone else to take the first step.

What is scarce is not sargassum. It is the information that tells an entrepreneur what will arrive, when, and in what condition. It is quality data that transforms an unpredictable input into a material that can be specified in a contract. It is the regulatory framework that gives investors the certainty needed to commit capital. None of these things is a market product. All of them are necessary conditions for a market to exist and grow

Correcting this imperfection is a major opportunity, and the good news is that these constraints correspond to an intervention that is technically feasible, institutionally achievable, and financially justifiable—something that can be pursued across three layers:

1. First, a regional infrastructure foundation: early warning systems, logistics before the factory gate, and quality monitoring as a public good.
2. Second, financial instruments that correct market failures keeping private investment below the social optimum.
3. Finally, a technological sequencing layer and mandatory quality standards that defines what gets built with the investment made viable by the previous layers.

The order matters: financing any layer out of sequence reproduces the outcome the region already knows. In our next entry, we will present suggestions on how each layer can be built and why sequencing matters as much as content.

The role of public and multilateral actors is decisive in organizing this sequence, reducing the uncertainty that currently paralyzes investment, and moving toward generating structural—not just reactive—solutions. The IDB Group stands ready to support these efforts and facilitate the necessary synergies between public and private actors.