Microplastic occurrence in deep-sea fish species Alepocephalus bairdii and Coryphaenoides rupestris from the Porcupine Bank (North Atlantic)

Microplastic occurrence in marine biota has been reported in a wide range of animals, from marine mammals and seabirds to invertebrates. Commercial and shallow-water fish have been the subject of numerous works on microplastic ingestion, given their importance in human diet and accessibility. However, little is known about microlitter occurrence in fish species inhabiting the dark ocean, in the bathyal zone and there is a high degree of uncertainty about microplastic distribution in offshore areas and the deep sea. In this study, bathydemersal species Alepocephalus bairdii and Coryphaenoides rupestris from the Porcupine Bank caught between 985 and 1037 m depth were inspected for microdebris. The stomach contents were digested by the alkaline method plus ethanol addition to avoid clogging. A filament of Polyethylene Terephthalate (PET) was found in the stomach of a specimen of A. bairdii, representing 4% of the total sampled specimens of this species (i.e. prevalence in n = 25). However, when considering potential microplastics, the prevalence increased to 28% in both, A. bairdii and C. rupestris. This work provides the first baseline study of microplastic items in fish from such depths in the Atlantic and suggests these species might be used as biomonitors in future research.