The effects of 17α-ethynylestradiol (EE2) on immature and mature males of the gilthead seabream (Sparus aurata L.) were studied. Gilthead seabream specimens were fed for 1 month with diets containing EE2 (5, 50, 125, 200 μg/g food). EE2 exposure altered the appetite, survival and digestive system in immature fish, and caused changes in the gonadal development, growth, survival, and some somatic indexes in mature males. The highest EE2 doses showed acute toxic effects (50% mortality) and liver injury. Gonad size was also drastically reduced
