3.1.3.3. Cephalopoda

The number of studies conducted on MP concentrations in cephalopods is lower compared to other classes. Ten species were investigated in nine articles (Appendix Table 1). Researchers examined MPs in the soft tissues, stomachs, gills, ink sacs, intestines, digestive glands, GITs, and outer bodies of squids, cuttlefishes, and octopuses. A majority of studies focused on the stomach. Most research used 10% KOH for tissue digestion, while FTIR was the predominant technique for polymer identification. The shapes of MPs were mostly fibers and fragments. The most commonly reported polymers were PET, PE, and PP. Studies have been conducted on mean MP ratios in several commercially important species in different regions, including Sepia officinalis on the Adriatic coast and in Portugal, Octopus vulgaris in the southern Tyrrhenian Sea and off Madeira Island, Loligo vulgaris in the northeast Atlantic, and Dosidicus gigas along western South America and in the eastern Pacific Ocean (Oliveira et al., 2020; Gong et al., 2021; Pedà et al., 2022; Armellini et al., 2023; Sambolino et al., 2023; Wang and Chen, 2023). The lowest rate of MPs per individual was reported as 0.13 ± 0.35 MPs/individual in the squid Ommastrephes caroli off Madeira Island in the Northeast Atlantic (Sambolino et al., 2023). The highest rate was 10.30 ± 16.66 MPs/individual in Octopus vulgaris in the southern Tyrrhenian Sea in the western Mediterranean Sea (Pedà et al., 2022).

Cephalopods need suitable shelters to protect themselves from predators due to their soft skin and to lay their eggs during the reproductive period. The literature has reported that they use marine debris as shelters. For example, the pygmy octopus Paroctopus cthulu was found to use a snorkel mask for spawning (Leite et al., 2021). Additionally, Freitas et al. (2022) reported that benthic octopuses used plastic marine debris as shelters for nesting and hiding.