Seaweed Aquaculture in Sweden has great potentials, study finds
Sweden has a long coastline with perfect conditions for seaweed cultivation, but current industry of edible macroalgae remains small. A research study now shows that Sweden has come a long way in the development of sustainable cultivation methods, and that there are good opportunities for an expansion of Swedish seaweed aquaculture.
Growing seaweed is a resource-efficient and sustainable way to produce edible food protein compared to the production of protein-rich plants on land, or animal proteins such as beef. However, there are still many challenges regarding sustainable ways to grow seaweed in Swedish waters.
Researchers from the University of Gothenburg have now conducted a systematic review of research articles summarising the latest advances in Swedish seaweed aquaculture research. The study highlights innovations and techniques that are tailored to sustainable seaweed cultivation, and which can hopefully lead to a boost in seaweed cultivation in Sweden.
“One of the most important conclusions is that we can show that seaweed aquaculture has great potential in Sweden and that we have come quite far in our development of efficient and sustainable production systems,” says Gunilla Toth, senior lecturer at the Department of Marine Sciences, who led the study.
The right cultivation site for the right algae
The most important seaweed cultivated in Sweden are the brown alga Saccharina latissima, also known as sugar kelp, and the green alga Ulva fenestrata, also known as sea lettuce. Research has so far largely focused on these species, and one of the conclusions of the study is that we need to increase knowledge about how we can grow more species in Sweden.
The coastal conditions in Sweden are partly unique, with small tidal ranges, an extensive archipelago that provides shelter from wave exposure on more open coasts, but also relatively large spatial variations in salinity and temperature. Therefore, it’s important to choose the right cultivation site for the right algae.
“We are currently conducting research to develop sustainable cultivation of several different macroalgae species, both those that can be cultivated in salty waters on the west coast, such as dulse, and in brackish waters in the Baltic Sea, such as gutweed,” says Gunilla Toth.
Protein content increases in wastewater
An important aspect of successful Seaweed aquaculture for food production is to increase the protein content of the algae, and several different research projects are underway, both at the University of Gothenburg and at Chalmers University of Technology. For example, using nutrient-rich process water from the food production industry.
“The most exciting part of our study is the part that summarises how both growth rate and protein content in sea lettuce increase when they are grown in wastewater from the herring industry. It's a new innovative method that our research group discovered recently, and it shows that you can turn something that’s seen as a problem in one industry into a resource in another,” says Gunilla Toth.
Writer: Annika Wall
Swedish consumption of seaweed is still small, around 100 tonnes per year (2022), and is mainly covered by imports. But in recent years, interest in algae in Sweden has increased.
Today, there are a handful of Swedish seaweed companies that together harvested just over 80 tonnes of algae in 2022.
The most common seaweed cultivated in Sweden is sugar kelp Saccharina latissima. The green algae sea lettuce Ulva fenestrata, and the red algae dulse Palmaria palmata, are among the algae in the start-up pit for cultivation.
Link to the article ‘Advances in Swedish Seaweed Aquaculture: Enhancing Biomass Production and Quality’ in Reviews in Aquaculture.
