After many fish changing sex pollution in Nashville, the transformed male emerges from its lair larger than before, bearing testes, a huge bulbous forehead, and an aggressive nature. Researchers are also probing the consequences of intersex for fish health.
However in other species, the sex skew can be more extreme: in the Potter Angelfish, Centropyge potterifor example, all fish start out lives as females, and all males were at one point female. Though less common than protogyny, male-to-female sex changes are found in a wide variety of fish, including the Australian barramundi Lates calcarifergilthead seabream Sparus aurata and the black porgy Acanthopagrus schlegeli.
One environmental estrogen is ethinyl estradiol—a chemical found in birth control pills. It fish changing sex pollution in Nashville less prevalent in largemouth bass—about 27 percent.
They were conducting a post-mortem examination to determine the causes of a smallmouth bass die-off when they found male fish with female egg cells fish changing sex pollution in Nashville their testes. Now even larger than the existing dominant male it had previously mated with when female, the new male defeats the aged alpha in a violent battle for dominance.
Amphibians, reptiles and fish employ a variety of methods to determine the sex of the offspring.
Experts say the new discovery in protected wildlife refuges is worrisome because it suggests that pollution may be even more pervasive than previously thought. We like to think of the far wilds of northern Vermont or Maine as pristine, explains Iwanowicz, yet the newest study serves as a reality check.
Exposures to endocrine disrupting chemicals in drinking water, food, and household products have been linked to health problems in people too, including reduced fertility, developmental delays in children, and some cancers. Other factors, such as chemical pollutants, changes in the acidity of the water, and the bacterial intestinal parasite Wolbachia can all affect the activity of aromatase in developing fish embryos.
However, no tests have occurred yet to identify specific chemicals. Some chemicals of concern include estrogens from birth control pills, the plasticizer bisphenol A, and the herbicide atrazine.