Marine pest makeover: Cambridge scientists grow “naked clams” from waste wood

22 Nov 2023 --- Using a process that has long eluded scientists, a team of researchers has cultivated shipworms, also known as “naked clams,” as a protein source. The trajectory to commercialization is still some way off, but the production mechanism has been verified.

“Finding alternative seafood options is critical. Our wild fish stocks are fished to their limit, and the expansion of aquaculture over the past 40 years has been unsustainable and fuelled by the expansion of a finfish sector reliant upon fishmeal and fish oil,” first author of the study, Dr. David Willer, Henslow Research Fellow at the department of zoology, University of Cambridge, tells Nutrition Insight.

“There is a need for nutrient-dense seafood alternatives to meet growing demand that do not place additional stress on our limited wild fish stocks.”

The saltwater clams are the fastest growing bivalve and can reach 30 cm in length in six months by burrowing into waste wood and converting it into nutritious protein. The team discovered that these bivalves are rich in vitamin B12 — higher than other species and twice the amount of blue mussels.

“They may be one of the earliest forms of aquaculture — we think that Aboriginal Australians have been cultivating naked clams for many years — and they are considered a delicacy in many places worldwide, including southeast Asia and Brazil. We’ve also shown that they are highly nutritious with low environmental impact,” senior study author Dr. Reuben Shipway from the University of Plymouth’s School of Biological & Marine Sciences, tells Nutrition Insight.

White meat alternativeNaked clams are an alternative source of protein being explored by researchers (Image credit: University of Plymouth).
Wild shipworms are eaten raw, battered and fried in the Philippines. The researchers believe the naked clams could be a popular white meat substitute in processed foods like fish fingers and fishcakes.

“We urgently need alternative food sources that provide the micronutrient-rich profile of meat and fish but without the environmental cost, and our system offers a sustainable solution,” says Shipway. “Switching from eating beef burgers to naked clam nuggets may well become a fantastic way to reduce your carbon footprint.”

A fully enclosed aquaculture system has been developed that can be controlled. The modular design can be used in urban settings, removed from the sea. The research team is experimenting with different types of waste wood and algal feed in the aquaculture system to optimize the clams’ growth, taste and nutritional profile. 

The research team, from the University of Cambridge and the University of Plymouth, are collaborating with Cambridge Enterprise to scale up and commercialize the system. Adding an algae-based feed will fortify the clams with omega-3 polyunsaturated fatty acids. The study has been published in the journal Sustainable Agriculture.

“They taste like oysters, they’re highly nutritious and they can be produced with a really low impact on the environment,” Willer continues. “Naked clam aquaculture has never been attempted before. We’re growing them using wood that would otherwise go to landfill or be recycled to produce food high in protein and essential nutrients like vitamin B12.”

Shipworms are the new oysters
The clams, scientifically called Teredinidae, were previously considered marine pests, mainly because they burrow through any seawater wood from ships, piers and docks. They do not have shells, and because they do not use energy to grow shells, they grow faster than oysters and mussels, which take up to two years to reach a harvestable size.The scientists have developed a viable aquaculture system for cultivating naked clams in wood (Image credit: University of Plymouth).

“If you look at how much environmental degradation there is across the planet, and then you see the rise in rates of health complications in relation to poor diet, then we clearly need new solutions to these problems. And Naked Clams are a potential solution,” Shipway explains.

The research has gained funding from The Fishmongers’ Company, British Ecological Society, Cambridge Philosophical Society, Seale-Hayne Trust and the Biotechnology and Biological Sciences Research Council.

“Our paper was the very first step in demonstrating that naked clam aquaculture was both feasible and desirable. Our plan now is to build further on this work by optimizing growth conditions and scaling the aquaculture so that you can enjoy delicious naked clams at your local fish and chip restaurant on a Friday night,” says Shipway.

Meanwhile, according to researchers in Haifa, Israel, a newly developed aquacultural process for growing seaweed enriched with proteins, dietary fiber, minerals and nutrients may help ensure food and nutrition security for generations.

By Inga de Jong