Influence of Ecotoxicological stressors on shrimp community dynamics in a polluted Niger Delta Estuary - Iko River, Eastern Obolo, Nigeria

Shrimps are highly nutritive seafood widely consumed in the Niger Delta. As benthic feeders, they interact with sediments that may contain environmental toxicants capable of altering their habitat’s physicochemical balance. To evaluate the ecotoxicological effects of environmental pollution on shrimp community dynamics in the Iko River Estuary, Eastern Obolo, Nigeria. Standard procedures were used to assess physicochemical parameters of water and sediments, and to determine shrimp diversity, abundance, and population structure as indicators of ecological health. Water temperature (27.50–28.05°C) and pH (7.13–7.55) were within limits, while conductivity, salinity, total dissolved solids, total hydrocarbons (122.39–141.60 mg/L), and nutrients exceeded NESREA standards, suggesting hydrocarbon and nutrient enrichment. Sediment pH (6.31–6.74) was slightly acidic with high conductivity and hydrocarbon content (139.09–156.14 mg/kg), dominated by sand (62.39–76.28%). Seven shrimp species were recorded, ranked in abundance as P. atlantica>P. setiferus>P. sculptilis>P. kerathurus>N. hastatus>M. rosenbergii>P. monodon. Sex ratios deviated significantly (χ², P < 0.05), and females showed higher condition factors. Low diversity indices (Simpson 0.63–0.74; Shannon 0.14–1.51) correlated negatively with hydrocarbon levels, indicating pollution-driven shifts. Shrimp communities in the Iko River Estuary exhibit low diversity and altered structure due to toxic contamination, emphasizing the need for sustained ecotoxicological monitoring and pollution control.