Measuring and comparing solutions for floating marine litter removal: Lessons learned in the south-east coast of the Bay of Biscay from an economic perspective

Abstract

Marine litter is a complex paradigm requiring innovative solutions. Public administrations are willing to contribute to counterpart marine litter but insufficient knowledge hindrance the progress. The integration of economic assessment in the decision-making may help to design knowledge-based solutions that guarantee a good marine litter management within the Blue Economy framework. Nonetheless, there is no clear methodology to do such assessments in the literature. In this study a new approach was implemented by assessing the effectiveness and the efficiency of four solutions designed to remove, monitor and/or manage floating marine litter (FML). In addition, the willingness to pay by local public administrations for purchasing such solutions was assessed. The solutions were tested in the inner waters of the Basque coast (South-Eastern Bay of Biscay), these being: the collection of FML by (1) a litter interception riverine barrier; (2) retrofitted fishing vessels engaged in the active Fishing for Litter; (3) sea-cleaning vessels operated with and without (4) a smart decision-support tool (LEMA Tool). The efficiency was measured by the cost of removing 1 kg of FML and comparing it to other alternative technologies; the effectiveness by a comparison of costs and benefits of removing marine litter for the local fisheries, aquaculture, ports and shipping and tourism sectors; and the willingness to pay was evaluated by Contingent Valuation Method. Results show that the density of FML affects the outcome of the efficiency, effectiveness, and willingness to pay and in return, the density depends on the operating ground and the season of the year among other factors. The most efficient solution is the cleaning vessels (4-7 EUR/kg of FML), followed by the Fishing for Litter fishing vessels (4-75 EUR/kg). LEMA Tool may improve the efficiency of both, fishing vessels and cleaning vessel, but the relative improvement depends on the knowledge of the fishers, the accuracy of the sea surface circulation models and again the local litter density. The barrier proved to be the least efficient solution (103 EUR/kg) and its efficiency depends on the river characteristics. Cleaning vessels are an effective solution, fishing vessel may be effective depending on the operating area among other variables. The willingness to pay of the public administration for purchasing technologies that enable the removal of FML is estimated as 1-8 EUR/kg. These outputs can provide good guidance for decision-makers to overcome the existing problem while prevention measures are implemented and take effect in the environment. Results highlight the possibility of having vessels engaged in the active and the passive Fishing for Litter, when the scopes of each activity are well defined, and overlapping is inexistent.