Details of plastic ingestion and fibre contamination in North Sea fishes

This study combines published datasets with unpublished data on plastic ingestion in several North Sea fish species. The combined dataset of 4389 individuals from 15 species allows the analysis of spatial distribution and temporal variability of plastic uptake in fish. Airborne fibre contamination was observed to be the main contributor to fibres encountered in the samples. The number of fibres in samples was strongly related to the time needed to process a sample, not to the number of individual fishes in the sample. Accurate correction for secondary fibre contamination was not possible, but corrections required would be similar to fibre numbers observed in the samples. Consequently, all fibres were omitted from further analysis. The frequency of occurrence and the average number of plastics in fish is generally low (1.8% and 0.022 pieces per organism respectively), with only cod having a higher prevalence (12.3%). While latitude of catch locations influences plastic uptake in fish, no correlation with the distance to the coast was found. Slightly less plastics were ingested in winter, and a decrease in plastics ingested was observed between 2009 and 2018. These factors should be considered when fish species, catch location and time are discussed as indicators for plastic pollution in the European Marine Strategy Framework Directive. We recommend considering demersal cod and pelagic sprat as two species suitable for monitoring plastic ingestion in biota, both on the seafloor and in the water column. [Display omitted] •In the North Sea among 4389 fishes from 15 species 1.8% contained plastic particles.•Temporal and spatial factors influence the uptake of plastics in fish.•Fibre abundance in samples is related to analysis time rather than direct ingestion.•Cod and sprat are suitable species for MSFD plastic monitoring in the North Sea. Although ingested plastic in fish from the North Sea is low, some species are suitable for monitoring programs. Fibre contamination during analysis contributes substantially to fibres found in samples.