Photo: University of Florida IFAS

Diving into Florida's Seaweed Potential: A Farmer's Reality Check

UNITED STATES
Monday, December 08, 2025, 00:10 (GMT + 9)

Dr. Aaron Welch of Two Docks Shellfish Company offers a cautiously optimistic view on developing a commercial seaweed industry in the Sunshine State, emphasizing the need for a viable market and high-value species.

Global seaweed production is reaching an all-time high, according to recent data from the World Bank and the FAO, but nearly all of it originates in Asia. While the United States' limited production focuses on cold-water species like kelp, researchers at the University of Florida (UF) IFAS have begun exploring opportunities for local macroalgae in Florida. The state seemingly possesses the right elements: a skilled workforce, existing working waterfronts, and an expansive coastline. However, significant hurdles remain, notably the lack of a commercial market and scarce data on the potential of native species.

Angela Collins of UF IFAS recently interviewed Dr. Aaron W. Welch, President of Two Docks Shellfish, LLC in the Tampa Bay area, and one of the state’s few active seaweed producers. Dr. Welch, whose family company has been in operation for 12 or 13 years and is involved in several research collaborations, offered an industry perspective on the future of this nascent market.

Dr. Aaron Welch III of Two Docks Shellfish shows off some of the day’s catch from Tampa Bay.(Photo: University of Florida IFAS) -->

Shellfish as the Core Business

Two Docks Shellfish currently maintains shellfish grow-out leases in Tampa Bay and Cedar Key, a small nursery in Pinellas County, and a hatchery in northern Manatee County. The primary commercial inventory is the northern hard clam (Mercenaria\ mercenaria), along with a small number of eastern oysters (Crassostrea\ virginica).

"I mean, I’m not in a cubicle... we get to do an amazing thing in an amazing environment," Dr. Welch stated, reflecting on his enjoyment of being a farmer who produces a product "from the beginning, from a seed."

In addition to commercial sales, Two Docks is involved in restoration efforts, having planted about one million Mercenaria\ campechiensis (Southern hard clam) in Charlotte Harbor as part of the A Billion Clams (ABC) program.

From Nuisance to Potential Product

For shellfish farmers, naturally occurring seaweed on their leases is generally considered a nuisance. It accumulates on shellfish bags, reducing water flow and creating an anoxic layer of decaying biomass that can stunt or kill clams. Dr. Welch explained that they spend a fair amount of time simply removing this "hassle" from their leases.

However, years ago, they began to wonder if there was an application for the material they were constantly pushing off their leases. This initial curiosity developed into a serious interest when a colleague introduced Dr. Welch to seaweed expert Loretta Roberson at Wood’s Hole Oceanographic Institution.

Through collaborations with Woods Hole, Two Docks secured grants to research the farming of species like Euchema and Gracilaria. Their early attempts, including a project to grow Euchema on a long-line array 2 miles off Anna Maria Island, faced numerous challenges, including excessive boat traffic and difficulties with growth. Later projects, which included an attempt to grow seaweed in a multi-species array with Sunray Venus clams, were hampered by environmental factors like hurricanes.

"Even though those grants didn’t necessarily turn out the way we’d hoped, we still learned a lot. We sort of learned what doesn’t work, for sure. That’s a start," Dr. Welch noted.

High-Value Possibilities: Bromoform

Dr. Welch is currently assisting with two UF and Sea Grant projects, including one focused on growing the red seaweed Gracilaria for bromoform production. Bromoform is a compound that has been shown to cut methane emissions from cattle by as much as 95% when fed in the right amounts.

The species of Gracilaria they are working with has a high bromoform content and can be grown in tanks. While the volume needed for a commercial cattle market is currently beyond the scale of Two Docks, Dr. Welch sees the potential.

"If there was an actual market, somebody could say, 'if you produce X, there’ll be a buyer... we could put pencil to paper and see if there’s a real business there."

Seaweed has applications for food, agriculture, and pharmaceutical markets. It is a sustainable product that also provides several ecosystem services, including the assimilation of nitrogen. (Photo: University of Florida IFAS)

The Fundamental Challenge: No Market

The largest obstacle to a viable seaweed market in Florida, in Dr. Welch’s view, is the fundamental problem of market absence. He believes that the global market for high-volume products like agar is operating at a scale Florida cannot compete with due to environmental challenges, such as poor summer growth and predation issues.

"The biggest one is there is no market for anything we can produce right now... Some of the markets that could potentially be tapped, I think operate at a scale that we’ll never be able to compete in."

This is where the Sea Grant research initiatives are crucial: they aim to identify native Florida species that contain high-value compounds for potential pharmaceutical or nutritional applications, which would not require the millions of tons of production volume needed for current commodity markets.

Seaweeds may present an opportunity for coastal communities and working waterfronts. UF researchers are working with industry partners to explore the potential of local macroalgae as a future aquaculture product. (Photo: University of Florida IFAS) -->

An Optimistic Outlook for the Long Haul

With a background in finfish aquaculture, including consulting work on large-scale offshore farms in Central America between 2006 and 2015, Dr. Welch is well-versed in global aquaculture trends. He believes that the changing dynamics of the global seafood economy will eventually necessitate domestic production.

"At some point, if the rest of the world keeps developing and getting wealthier, we’re not going to have the buying power that we have today, so I think over the long haul the business is going to continue to grow."

The most exciting aspect of seaweed production for Dr. Welch is that it could leverage existing aquaculture infrastructure and working watermen, minimizing the need for large amounts of new capital investment. Furthermore, he highlights seaweed's potential as an environmental mitigation tool by absorbing excess nitrogen, suggesting that nutrient credit markets could provide another avenue for financial sustainability.

Despite the challenges, Dr. Welch emphasized that success in aquaculture is hard-won. "We have failed way more than we have succeeded... it’s not easy." He and his team remain the only aquaculture business in Florida actively involved in funded seaweed research, pursuing the hope that science can define a profitable market for this underutilized resource.

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