Global production of plastics has increased dramatically in recent decades and is considered a major threat to
marine life and human health due to their stability, persistence, and potential to move through food chains. The
study was conducted to detect, identify and quantify microplastics (MP) in the gastrointestinal tract (GI) of some
commercial fish species in the North Persian Gulf in Bushehr Province: Psettodes erumei, Sphyraena jello, Sillago
sihama, Metapenaeus affinis and Portunus segnis. A total of 216 plastic particles were collected from 102 individuals (72.68% of all sampled individuals; MP prevalence of 85.1% for M. affinis, 80% for P. segnis, 70% for P.
erumei, 60.3% for S.sihama, 45.2% for S.jello). The average number of microplastics per organism was 2.26 ±
0.38 MP/ind (considering only species that ingested plastic, n = 102) and 1.51 ± 0.40 pieces/ind (considering all
species studied, n = 140). Microfibers accounted for 58.49% of the total microplastics, followed by fragments
(33.02%) and pellets (8.49%). The most common color of microplastic was black (52.83%), followed by blue
(22.64%) and transparent (15.09%). The length of microplastic ranged from 100 to 5000 μm with an average of
854 ± 312 μm. Microplastics were significantly (p < 0.05) abundant in two shrimp studied: M. affinis and
P. segnis (plastic in 80% of individuals studied) and to a lesser extent in the pelagic barracuda fish S. jello (plastic
in 45% of individuals studied). The main synthetic polymers identified by Fourier transform infrared spectroscopy (FTIR) were polyethylene (38%), polypropylene (24%), polystyrene (17%), polyethylene terephthalate
(11%) and polyamide (10%). The pollutant load index and lifetime accumulation index were calculated to
identify the most polluted species and their toxicity to human health. The white shrimp M. affinis was identified
as the most polluted and toxic species for MP based on PLI. The present study can provide valuable data for
further researc