Underwater fields of seagrass could play an important role in fighting malnutrition among vulnerable coastal communities, according to new research published in Cell Reports Sustainability. The study was carried out by scientists from Stockholm University and Project Seagrass. It found that fish caught in seagrass meadows provide a stronger combination of essential nutrients than fish collected from nearby coral reefs.The research team studied fish populations across 20 seagrass meadows and 20 coral reefs along a 3,000-kilometre stretch of the East African coastline, covering areas between Kenya and Mozambique. Millions of people living in these tropical regions depend heavily on fishing for food and income, while many communities continue to face poverty and nutritional challenges.Instead of looking at nutrients separately, researchers examined the overall nutritional value of the fish as a complete food source. They measured six important nutrients needed for human health: calcium, iron, zinc, selenium, vitamin A and omega-3 fatty acids.The results showed that, after adjusting for fish weight, fish communities living in seagrass meadows were on average 1.6 times more nutritionally dense than those found around nearby coral reefs.“Fish don’t nourish people one nutrient at a time,” said Dr Benjamin Jones, chief conservation officer at Project Seagrass, who led the research during his doctoral studies at Stockholm University. “They come as a package. A single fish contains iron, zinc, calcium, selenium, vitamin A and omega-3s. We wanted to understand which habitats produce fish with the best mix of these nutrients.”
Seagrass meadows act like nature’s supermarket
The difference became even clearer when researchers looked at the fish species most commonly caught and eaten by local communities.For the three most important food fish species in the region, the nutritional support provided by seagrass meadows was more than eight times higher than that from coral reefs.Species such as rabbitfish and parrotfish, which are important sources of food for coastal populations, were much more common in seagrass areas. Rabbitfish were found to be five times more abundant in seagrass meadows compared with coral reefs, while parrotfish were 65 times more common.“We know that coral reefs have more fish overall, but seagrass meadows had more of the fish that really matter for local food,” Jones stated. “This changes how we should think about these habitats. Seagrass isn’t just a fish nursery, nor just a carbon stock, it’s food infrastructure, nature’s own supermarket.”The health benefits could be significant for coastal families. The study found that eating one average fish caught from a seagrass meadow could provide a young child with around 5% of their daily iron needs, 21% of their zinc needs and 70% of their selenium needs.
Protecting more than just coral reefs
The findings challenge the traditional focus of marine conservation, which has often placed coral reefs at the centre of global protection efforts. Coral reefs remain extremely important and are under serious pressure from overfishing and rising ocean temperatures.However, seagrass meadows are also disappearing quickly due to coastal construction, industrial waste, damage from human activity and pollution carried by rivers from farms and cities.The researchers argue that conservation efforts need to consider both ecosystems because they support human communities in different ways.“If we lose seagrass meadows, we are not just losing habitat,” Jones warned. “We may be losing a source of nutrition for millions of people who need it most.”The study does not suggest replacing coral reef protection with seagrass conservation. Instead, researchers say both environments need support because they perform different roles.Coral reefs produce a larger amount of fish overall, while seagrass meadows provide greater access to certain food fish that contain valuable combinations of nutrients.“Reefs and seagrass meadows work together,” Jones said. “If we want coastal fisheries to feed people, we need to protect the whole seascape.”
Protecting seagrass grom human activity
Saving these underwater meadows will require action beyond the ocean itself. Researchers say many of the biggest threats to seagrass begin on land.They recommend stronger investment in sewage treatment systems, cleaner rivers, reduced agricultural pollution and fairer fisheries management to protect both ecosystems and the people who depend on them.The study also discusses a possible problem linked to growing interest in blue carbon markets, where companies invest in ecosystems like seagrass because they store carbon. Researchers warn that conservation projects must not prevent local communities from accessing traditional fishing areas.The authors stress that protecting seagrass must include the people who rely on it for food and livelihoods.“Seagrass conservation has to be about people as well as nature,” Jones concluded. “These meadows store carbon, support biodiversity and help feed millions. That makes them one of the most important ecosystems on Earth.”
