Plastic pollution is increasing dramatically worldwide, causing adverse effects on a wide variety of marine organisms at all trophic levels. As predators, sharks play a key role in marine ecosystems and they could especially be threatened by the ingestion of microplastics. This study contributes to expand the existing data on the MPs ingestion by a Mediterranean elasmobranch species, Scyliorhinus canicula, adding new information on the potential impact that this class of contaminants can have on the metabolism of this ecologically relevant species. The present research is aimed: i) to assess if the ingestion of MPs in S. canicula is related to sex, size and depth of catch; ii) to evaluate the effect of MPs on fish body condition; iii) to evaluate if the ingested MPs influence the amino acid and fatty acid composition of eye and liver. A total of 61 specimens of S. canicula were analysed. Forty-nine individuals (80.3 %) had ingested plastic items. Totally, 147 plastic elements were found, mainly belonging to small MPs (49 %), and large MPs (46 %), mostly represented by fibers (84 %). The predominant colour was black. No differences were found between sex and size. A difference in the number of items/specimens related to the deep, highest between 50 and 100 m (4.4), while the lowest between 101 and 500 m (2.1) was found. The condition factor (Kn) value was equal to 1.00 highlighting the wellness of the fish. Arginine (20.1 %), Glutamate (17.4), Phenylalanine (15.7 %), Proline (15.6 %) and were the most abundant amino acids in the eyes of S. canicula. The relative fatty acid composition of the livers was dominated by fatty acids SA (30.2 %) (SFA), CA (29.9 %) (SFA) and OA (22.4 %) (MUFA). This paper reports a study on the relationship between amino acids and fatty acids composition and ingested MPs, highlighting that no significant effects were found.
Keywords: Amino acids; Effects; Fatty acids; Marine pollution; Microplastics; Small-spotted catshark; South of Sicily.
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