Assessing microplastic pollution in the gastrointestinal tract of green tiger prawns (Penaeus semisulcatus, De Haan, 1844) caught off the west coast of the Arabian Gulf, Saudi Arabia

The present study investigated the level of microplastic (MP) contamination in the benthic environment of the Arabian Gulf waters of Saudi Arabia for the first time. The green tiger prawn, Penaeus semisulcatus, a commercially valuable shrimp species, was chosen to assess MP pollution. This study examined the gastrointestinal tracts (GT) of 101 composite shrimp samples collected from trawl catches at two fishing harbors. Following morphometric measurements, the GT samples were subjected to alkali digestion, vacuum filtration, and microscopic examination. Suspected particles were further validated using LUMOS II FTIR microscopy with micro-ATR-FTIR, enabling reliable polymer identification. A total of 238 MPs were found, with an average of 2.93 ± 1.63 MPs sample⁻¹ (n = 5 individuals per sample), corresponding to 0.47 ± 0.50 items individual⁻¹. Grey (33%) and red (27%) MPs were the most common, with particles in the 251–1000 µm size range being the most dominant. Fibers constituted 90% of the MPs in P. semisulcatus, while films made up only 10% of the total abundance. Significant variation in MP ingestion occurred among shrimp size groups, with smaller individuals showing higher proportions of colored fibers. Six types of polymers were identified, with Polyethylene terephthalate (PET) as the most dominant (30%), followed by Polyamide (PA) at 20%, Polyacrylamide (PARA) at 16%, Polypropylene (PP) at 15%, Polyethylene (PE) at 13%, and Thermoplastic vulcanizate (TPV) at 6%. Shrimp samples from both regions had low PLI values (< 10), with PA posing the highest ecological risk due to polymer abundance rather than toxicity. The findings have implications for seafood safety, environmental monitoring, and ecosystem health, highlighting the need for more research on MP pollution sources in the area.