Discipline: Veterinary Medicine
The importance of Laguna de Bay in Luzon, Philippines as a natural resource necessitates routine monitoring of its environmental quality. In addition to water quality tests, however, there should also be a focus on the impact of existing conditions on the aquatic biota. There is currently a paucity of published data on the biologic impact of pollutants in the lake. The present study measured the biomarkers of exposure to pollution, namely, hepatic melanomacrophage centers (MMCs) and hepatosomatic index (HSI), in male common carps (Cyprinus carpio, Linnaeus, 1758) caged for 30 days along the east and west bay of the lake. In comparison to the reference group, caged fish exhibited a greater number of MMCs (p<0.01) that were also of bigger size (p<0.05). Further evaluation revealed the presence of lipofuscin, hemosiderin and melanin pigments in the treatment groups although a greater percentage of the last two pigments was noted in caged fish. HSI, which is also used as an indicator of nutritional and energy status in fish, was also low in this group (p<0.05). The results suggest differences in the environmental quality to which the treatment groups have been subjected with observations in caged fish potentially attributable to pollutant exposure.