Microplastics in Shortfin Scads (Decapterus Macrosoma) in Northern Philippines

Abstract

Microplastic pollution poses persistent threats to marine ecosystems and human health via seafood consumption. This study quantified prevalence, abundance, and morphology of microplastics in shortfin scads (Decapterus macrosoma), a key pelagic fishery species, from National Stock Assessment Program (NSAP) sites in Ilocos Norte, Pangasinan, and Cagayan. Twelve specimens (3/sites x 4 NSAP sites) underwent gastrointestinal tract dissection, 10% KOH digestion at 80°C, density separation, and Nile red staining under fluorescence microscopy for identification. Microplastic prevalence varied spatially: 66.67% in Pantal, Dagupan City (Pangasinan; 1-6 particles/specimen), 33.33% in Palawig, Sta. Ana (Cagayan) and Poblacion 1, Pagudpud (Ilocos Norte; 1-2 particles), and 0% in Taggat Norte, Claveria (Cagayan). Dominant forms were fragments (irregular shapes) and fibers (linear), exhibiting intense orange fluorescence indicative of synthetic polymers. Findings establish baseline contamination patterns linked to coastal anthropogenic activities, highlighting risks to food safety and SDG 14 (Life Below Water). Enhanced monitoring, waste management, and polymer-specific analyses are recommended to mitigate pelagic fishery impacts.