Microplastic Ingestion, Polymer Characteristics, and Ecological Risk in Commercial Pomfret Fishes Pampus chinensis and Pampus argenteus from the Bay of Bengal.

Microplastic (MP) contamination is a growing environmental challenge, affecting marine biodiversity and fisheries on a global scale. This study quantified the abundance, physical characteristics, and polymer types of MPs in the gastrointestinal tracts of two key fish species, Chinese silver pomfret (Pampus chinensis) and white pomfret (Pampus argenteus), collected from the offshore fishing grounds of Bangladesh during March 2024. A total of 25 adult specimens per species were analyzed via oxidative digestion, density separation, and filtration. The polymers of the isolated MPs were identified using Fourier Transform Infrared Spectroscopy (FTIR). MPs were detected in 100% of specimens, with mean abundances of 20.0 items/fish in P. chinensis and 6.6 items/fish in P. argenteus. Fiber-shaped (59-64%) and transparent (53-65%) MPs, predominantly < 500 µm, were most common. Polyamide (PA) and polyethylene terephthalate (PET) were the main polymers. Ecological risk assessment using the Polymer Hazard Index (PHI) indicated the presence of high-risk polymers, but the Pollution Load Index (PLI) suggested overall minor MP contamination relative to the reference baseline. These findings highlight the widespread occurrence of MPs and the predominance of fishing-related polymers in offshore pomfrets of the Bay of Bengal. Notwithstanding the limitations of our sample size and spatial scope, these initial results provide first evidence on the need for regionally coordinated monitoring, improved plastic waste management, and further research on biological effects and food web transfer in tropical marine systems.