About This Project

Cost–benefits analysis actions and societal perceptions to reduce marine litter


Villasante, S. et al. (including Pita, P., Herrera, M.) (2021).


Marine litter produces an extensive variety of negative environmental, economic, safety and health effects, including impacts on maritime cultural heritage. The economic impact of marine litter is highly relevant and manifests itself in numerous ways. The negative effects of marine litter on the marine environment and on people who directly or indirectly depend on the oceans, may endure for hundreds of years. Thus, people living in industrialized and urbanized areas with high concentrations of plastic debris are especially vulnerable to negative environmental impacts and derived ecosystem services, including reductions in the availability of healthy food.


Therefore, given the multiple effects at all levels, the problem must be approached simultaneously through different solutions. Coastal ecosystem services (ES) can be significantly altered by marine litter, because of its multiple economic and social impacts at different scales, from the local to the international level. The presence of marine litter has significant documented impacts on the marine environment (e.g. degrading inland, coastal and open-sea ecosystems). Overall, most sectors of the population are aware that degradation of ecosystems can have a negative effect on the economy (e.g. revenue losses in the fisheries, tourism and shipping sectors) and on society (e.g. affecting the health and well-being of residents and visitors). However, current scientific evidence of the economic impacts of marine litter in Portugal and Spain is still scarce.


The NetTag project comprises several lines of actions, including the development of innovative technological proposals, focused on mitigating the problem of marine litter derived from the loss of fishing gear, as well as the development of awareness-raising actions. Therefore, one of the objectives of the NetTag project is to evaluate the main perceived effects of marine litter on ES and coastal communities, as well as to assess the cost-benefit of the NetTag solutions to reduce marine litter derived from lost fishing gears. By conducting 360 individual interviews along the Rías Baixas coastal region (Galicia, Spain) we analysed societal perceptions about the importance of ecosystems for human well-being and the magnitude and consequences of marine litter on marine-coastal ecosystems. The surveys included sections related to sociodemographic characteristics of the surveyed population, marine ecosystem services affected by marine litter and mitigation-management actions.


On the other hand, to estimate the costs and benefits related to the development of novel technological solutions aimed to mitigate the fisheries-derived marine litter, we used the information obtained from the semi-structured interviews and participatory workshops with key actors from the fishing industry, such as fishers or fishing gears producers, allowing us to gather economic information. The technological solutions developed by the project consists of small and cost-effective transponders that when attached to a fishing gear can be located by a hydrophone, and an underwater robot with different capabilities, from video signal to recovering gear autonomously.


Our results indicate that the surveyed populations maintain a close relationship with marine ecosystems and they are also highly aware of the consequences of marine litter to the detriment of the ES provided by coastal areas (81.1% of interviewees considered marine litter impact as high; n=292). The results also suggest that the conservation of habitats for marine life (92%, n=332) and well preserved biodiversity (85%, n=307), along with provisioning ES (88%, n=316) are scored as very important by the interviewees in general, even above recreational ES (56%, n=200). In addition, the fisheries sector has been perceived as the least responsible for pollution caused by marine litter (only 46%, n=165, considered them very responsible), with a wide awareness of the role of citizens in both the cause and the solution. Our cost-benefit analysis shows that the average ship-owner would recover the economic investment made on the technological solutions developed by the project (transponders and underwater robot) after 8-10 years, simply by saving time and costs derived from the search for lost gear.

2021, Technical Reports
Mariana Herrera, Pablo Pita, Sebastián Villasante