FUNCTION AND CONTAMINATION: LINKING GUT MORPHOLOGY TO DIET AND ASSESSING MICRO PLASTIC PREVALENCE IN A NIGERIAN RIVER FISHERY

This study investigated the relationship between gut morphology, diet, and microplastic prevalence in ten fish species from the Baro River, Nigeria, to understand how feeding ecology influences contamination risk. Morphometric and gut content analyses were conducted to determine trophic guilds, while microplastic presence was assessed from the digestive tracts of the sampled species. Results revealed that omnivorous, insectivorous, and planktivorous species showed higher rates of microplastic ingestion (up to 40% occurrence), while herbivorous species had no detectable plastics. Relative Gut Length (RGL) analysis supported the ecological principle of “form follows function,” with herbivores exhibiting longer guts suited for fibrous diets and carnivores' shorter ones for protein digestion. Findings demonstrate that feeding ecology significantly influences exposure risk to microplastics, posing threats to aquatic biodiversity, food safety, and fisheries sustainability. This research establishes a vital baseline for integrating morphology, diet, and pollution studies in Nigerian inland fisheries and provides recommendations for sustainable management and pollution control.