The purpose of this report is to provide recommendations, advice and practical guidance, for the establishment of programmes to monitor and assess the distribution and abundance of plastic litter, also referred to as plastic debris, in the ocean. The intention is to promote a more harmonised approach to the design of sampling programmes, the selection of appropriate indicators (i.e. type of sample), the collection of samples or observations, the characterisation of sampled material, dealing with uncertainties, data analysis and reporting the results and also to inform the establishment of national and regional field monitoring programmes.
The main audience of the report is intended to be national, inter-governmental and international organisations with responsibilities for managing the social, economic and ecological consequences of land- and sea-based human-activities on the marine environment. The decision to produce these Guidelines reflects the lack of an internationally agreed methodology to report on the distribution and abundance of marine plastic litter and microplastics, a topic that is attracting increasing concern.
The Guidelines cover all size ranges of plastic litter encountered in the marine environment, on shorelines, floating on the sea surface, suspended in the water column, deposited on the seabed or associated with biota (ingested / encrusted / entangled). They may be used for the monitoring of items originating from specific sources (e.g. Abandoned Lost or otherwise Discarded Fishing Gear, ALDFG) or specific items to evaluate the efficiency of dedicated reduction measure (e.g. single-use consumer plastics, sanitaryrelated items). Hence, This document is intended to inform the establishment of national and regional field monitoring programmes. It provides links to protocols and data recording sheets that are intended be used in the field. The scope is restricted to monitoring plastic litter in the marine environment.