Effects of the Ixtoc I Oil Spill on the Intertidal and Subtidal Infaunal Populations Along Lower Texas Coast Barrier Island Beaches

Pre-spill (August 4 to 11, 1979) and post-spill (September 24 to 29, 1979) sampling of intertidal and subtidal infaunal populations along lower Texas coast sandy beaches was conducted to determine the impact of the Ixtoc I oil spill. Transects sampled between the Rio Grande and Port Aransas produced 52 species of macroinfauna primarily dominated in abundance and diversity by polychaetes and haustoriid amphipods. Analyses revealed visible, though not significant, decreases in pooled intertidal population densities and significant reductions in pooled subtidal population densities. Numbers of species did not significantly change. Population density changes may have been caused by Ixtoc I impact, tropical depression/storm beach erosion, seasonal fluctuations, beach cleanup techniques, or a combination of these.