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.

The Spanish Bottom Trawl Survey on the Porcupine Bank (SP-PORC-Q3) was funded in part by the EU through the European Maritime and Fisheries Fund (EMFF) within the Spanish National Program of collection, management and use of data in the fisheries sector and support for scientific advice regarding the Common Fisheries Policy. L. Soliño and L. Vidal were funded by the CleanAtlantic Project (EAPA_46/2016): “Tackling Marine Litter in the Atlantic Area” funded by the INTERREG Atlantic Area Programme (2014–2020). P. Pérez work was funded by the 6-ESMARES2-C8 project, which is supported by the Spanish Ministry for the Ecological Transition and Demographic Challenge. Thanks are due to Thermo Fisher Spain for their help and assistance with Raman measurements. The authors would like to thank the reviewers for their relevant comments which significantly contributed to improving the initial manuscript. This study was carried out in the framework of the CleanAtlantic Project (EAPA_46/2016): “Tackling Marine Litter in the Atlantic Area” funded by the INTERREG Atlantic Area Programme (2014–2020). It only reflects the author's view, thus the Atlantic Area Programme authorities are not liable for any use that may be made of the information contained therein.

Peer reviewed