Nevertheless, regression analysis revealed the sampling season to be the main factor affecting PCB 153 levels, in accordance with results reported by Serrano et al., 2008a.As regards to the collection site effect, interestingly, PCB 118 presented significantly higher values in fish collected from open seas, while PCB 28 and PCB 52 present significantly higher values in fish collected from closed seas. Furthermore, PCB 28 appeared to be mainly influenced by farming site, besides sampling season, in the regression analysis models carried out in our study.