Microplastics in the stomach and intestine of pelagic squid: A case study of Dosidicus gigas in open sea of Peru

Microplastic (MP) ingestion by marine animals has been well documented, but less being known about pelagic squid. Jumbo squid supports the world's largest cephalopod fishery and plays an important ecological role in the Eastern Pacific Ocean. In this study, taken from the open sea of the Peruvian Exclusive Economic Zone were selected as research objects. We estimated the abundance and characteristics of MPs in the stomach and intestine of and investigated the differences between tissues and sexes. Similar abundance and characteristics of MPs were observed in the same tissue of females and males. However, the stomach had a higher abundance of MPs with larger size than the intestine, while the MP abundance by stomach wet weight was lower than that of the intestine. The MPs were predominantly fiber-shaped, with blue or black color. The most frequent polymers were high-density cellophane and polyacrylic acid. These polymers could sink into deeper sea layers and were available for living there during the daytime.