Plastic for dinner? Observations of frequent debris ingestion by pelagic predatory fishes from the central North Pacific

Abstract

There have been numerous reports of plastic debris accumulation in surface waters of the central North Pacific Subtropical Gyre. Further, incidences have been reported of plastic ingestion by different marine organisms, including seabirds and small planktivorous fishes. Diet studies (2007 to 2012) of predatory pelagic fishes from this general region showed repeat observa- tions of anthropogenic marine debris ingestion in 7 species (n = 595 individuals examined). Inci- dence rates ranged from <1% in Gempylus serpens to 58% in Lampris sp. (small-eye). Of all indi- viduals 19% contained some form of marine debris, the majority of which was some form of plastic or fishing-related line. Surprisingly, species with the highest incidences of debris ingestion are thought to be primarily mesopelagic and unlikely to come into contact with surface waters con- taining known debris fields. Ingested debris pieces were found to be positively buoyant in seawa- ter mimicking different depths. These observations are the first of their kind in scope and number, and suggest that more attention should be given to marine debris in subsurface waters as well as to poorly understood organismal and food web implications.