Estrogenic Effects in Feral Male Common Carp (Cyprinus carpio) from Laguna de Bay, Philippines

This study was conducted to measure 17β-estradiol (E2) levels in Laguna de Bay, Philippines and to examine feral male common carp for evidence of exposure to estrogenic pollutants. Analysis of water samples revealed E2 concentrations of 630 and 550 ng/L from the east and west bay of the lake, respectively. Plasma vitellogenin (VTG) in captured fish ranged from 506 to 4083 ng/mL. In comparison to the reference and west bay groups, fish from the east bay had higher plasma VTG concentrations and reduced gonadosomatic index (GSI). Ovotestis was not observed although some individuals had endocrine-related histopathological alterations in the testis. The degree of biologic effects induced by estrogenic pollutants in tropical freshwater systems like Laguna de Bay need to be further investigated to provide a better comprehension of the fates and effects of these compounds under tropical conditions.