To evaluate the impact on biota of the release of ~2 million liters of bunker oil off Guimaras Island, central Philippines, the penaeid shrimp populations in a protected island mangrove (Tandog) and a riverine mangrove (Sibunag) were surveyed by pocket seine 2-3 months after the August 2006 spill; results are compared to 1993 baseline data. A total of 529 individuals belonging to three penaeid species were collected – Metapenaeus anchistus in Tandog, and M. ensis and Penaeus merguiensis in Sibunag. Shrimp densities were significantly higher In Tandog Island in 2006 compared to 1993 but remained similar in the riverine mangrove. This suggests that protection may have a greater impact than the Oil Spill per se because Tandog is part of the protected Taklong National marine Reserve. In contrast to abundance, shrimp sizes (carapace length) were significantly smaller in 2006 comparted to 1993 for both sites.