Oceans, seas, lakes and other waterbodies are increasingly suffering from too much plastic waste. Numerous sources are contributing to this plastic waste problem. Additionally, conventional fishing nets, made out of nylon, are causing environmental damage by disintegrating into microplastics. The breakdown process stops there, as these microscopic particles are non-biodegradable. Microplastics remain in waters for years causing harm to marine organisms that ingest them. Linen fishing nets are a valid alternative and more ecological production of nets. This study aims to compare the costs of these new linen nets with conventional nets. These costs can be related to the environmental benefits of these alternative nets. The research objective is to study the question under which conditions it would be optimal to choose linen nets over conventional (nylon) fishing nets. The conditions examined are economic and policy, environmental and technological. This research question is put into the wider context of microplastics. A rotation model, typically used in forest economics, is applied to analyze the optimal lengths of periods to renew both a linen and a nylon fishing net. A comparison of the costs is conducted and a subsidy-based policy instrument is determined for the fishers using linen nets.
A subsidy-based policy could be applied to make fishing enterprises in Finland use ecological fishing gear. The results suggest that the costs of such a policy would be reasonable, estimated between €1.1 and €4.5 million in this study. Importantly, an increase in the use of ecological nets would lead to a decrease in the total microplastic load in waterbodies.