The BSAF values were calculated for each pair of observations and then averaged. It is interpreted to mean that the higher the BSAF, the higher is the degree of accumulation. Additionally, this study having more than one independent variable, multiple regression was used to establish the best predictor variables in the concentration of Cu, Pb and Zn in the C. macrocephalus which could be utilized by future studies focusing on the Butuanon River as these equations would provide the relationship of metal concentration in the organism with several independent variables. Multiple regression is a straightforward way to accommodate ancillary variables