Fishing nets lost at sea are a major source of plastic pollution in the ocean. These so-called 'ghost nets' drift around the world, ensnaring and killing fish, dolphins, seals, birds and sea turtles. Now a South African/Swedish joint venture wants to put an end to the problem with compostable fishing nets.
Fishing nets lost at sea are a major source of plastic pollution in the ocean. These so-called “ghost nets” drift around the world, catching and killing fish, dolphins, seals, birds and sea turtles. They can last up to 600 years and release microplastics as they slowly break down.
Now the South African initiative Catchgreen is developing a solution. By making nets and other equipment from compostable Biodolomer, a net lost at sea would break down into biomass within a few years. They also have a higher density, so they sink to the bottom of the ocean where they cause less damage and are subject to microbes that speed up the decomposition process.
“Biodolomer nets will not only reduce ghost fishing,” says Emma Algotsson, project leader at Catchgreen and CEO of Kompost-It. “It will reduce the amount of microplastics in the ocean. And old nets can be taken to industrial composting facilities and converted into biomass.”
Biodolomer was invented by packaging material specialist Åke Rosén, who has been instrumental in developing many materials for Tetra Pak and has more than 65 patents to his name. It has been produced and marketed by Gaia Biomaterials in Sweden since 2015 and is used for everything from shopping bags to beer cups and agricultural cover films.
“It is a material that has all the characteristics of plastic that a user wants, but it is compostable,” says Peter Stenström, CEO of Gaia Biomaterials AB.
“Industries all over the world are finding new applications for it. And we regularly develop customized versions. For example, by changing the composition we can change elasticity and the time it takes for the final product to decompose.
Unlike some bioplastics, Biodolomer does not release microplastics and uses a very limited amount of natural resources. Limestone is an important ingredient in most Biodolomer products.
“Limestone is one of the most abundant minerals on the planet,” notes Stenström. “And when Biodolomer decomposes, the water, CO2 and soil are enriched with calcium carbonate.”
Developing compostable fishing nets has been challenging. Emma and the team at Gaia Biomaterials have spent years creating a suitable substrate for the wires used in larger nets, working closely with South African net manufacturers.
“In 2023, we conducted field tests with drift nets in Kenyan waters. We are also working on biodegradable ropes and nets for restoring coral, seaweed and kelp. The ultimate goal is to test the material for trawl nets.”
Catchgreen is partly funded by the UK government's Sustainable Production and Environmental Tax (SMEP) programme. SMEP is implemented in collaboration with the United Nations Conference on Trade and Development (UNCTAD).
Catchgreen fishing nets are expected to hit the market in 2024.
Photo: Catchgreen
