Supplementary file 2_Microplastic contamination in the endemic Fiji maskray (Neotrygon romeoi).docx

Plastic waste accumulates in coastal environments, posing risks to marine organisms and the human communities that depend on them. Fiji relies heavily on inshore fisheries, yet the extent and physiological implications of microplastic (MP) contamination in locally captured species remain unclear. Most existing work has focused on MP contamination in teleosts, with little information for batoids, particularly from South Pacific islands. In Fiji, batoids are a common component in small-scale fishery activities, with the endemic Fiji maskray (Neotrygon romeoi) frequently captured and traded. To provide a first reference for a batoid from this region, we quantified MP contamination in 21 Fiji maskrays from the Suva–Rewa–Tailevu corridor, characterized particles by size, shape, and color, and assessed physiological condition using the hepatosomatic index (HSI). Furthermore, to address a key life history gap relevant to management, we estimated size at maturity for both sexes, finding that females matured at 360–365 mm disc width and males at 369–395 mm disc width. Microplastics occurred in 71.4% of specimens, with a mean of 6.76 ± 7.80 particles per individual and no significant difference between stomach and intestine (p = 0.331). Particle sizes ranged from 63 to 500 µm, with 63 µm being the most frequent. Fragments predominated, with white (n = 38) and silver (n = 33) being the most common. No statistically significant relationship was found between MP presence and HSI, despite a weak to moderate negative trend. Together, these results establish a baseline for MP contamination and provide complementary life history information to support future contamination assessments and fisheries management.