The change of sex in fish

The Change of Sex in Fish
Paulina Bernáldez De Loera
CEDI A.C.

Abstract
In the animal kingdom, there are a lot of specimens and species that share the ability and capacity of changing their sex. Many of these animals or better said most of them are aquatic animals. These species are capable to do so thanks to the hormones produced by their endocrine system and their simple sex organs. Therespecific terms to name the changes of sex going from male to female and vice versa, as well two different types of hermaphroditism. There are also many ways in which the change of sex is manifested in these species. Some of them change their size when they change of sex. Some others change their coloration. This ability is used basically by fish as a strategy to maximize their survival.

TheChange of Sex in Fish
The change of sex as an ethical conflict among the society
There has always been polemic about how women are so much complicated and how it is so difficult for men to understand them. On the streets we see men dressed up and behaving as if they were women and we see women behaving as men. Then we see men mating with other men and women mating with other women. Now a day wehave advanced in modifying sex either on men as in women, but this is done in an unnatural way.
The change of sex in animals
Nevertheless there are organisms (in the majority aquatic) with very simple reproductive systems, which experience a change of sex at some point in their lives. Some examples are nematodes worms, shrimps and mollusks. Inclusively there are also some complex organisms likethe fish that have also the ability to change sex, some of them can act as sequential hermaphrodites. In fact the change of sex is a common strategy in aquatic organisms for survival.
Hermaphroditic fish
When a fish has the capability to change from male to female, from female to male or even have both genders at the same time they are called hermaphroditic. There are two types of hermaphroditicfish. The first type of hermaphrodites could potentially mate with any other individual in their species because their sex organ is divided into both male and female. Their sexual cells (testes and ovaries) occur in the same individual. Other fish are sequential hermaphrodites and these fish change sex at some point in their lives (Jungwi, 2009). There already exist specific terms for determiningthe patterns for sex-change. We called them protandry those fish that are males and switch to females. And for those fish that are females and switch to males the term applied to them is protogyny. Some other species can change their sex more than once, going back and forth between genders (Jungwi, 2009).
How they change of sex
Change of sex in the fish is due to the many hormones orchemical substances that are produced by their endocrine system. The gonads which are the sex organs of the fish receive hormones released by the endocrine system. As the same time, thanks to their simple structure they secrete also hormones in exchange these hormones stimulate the hypothalamus, which in turn, stimulates the pituitary to release specific hormones that have the function to make a femalegonad into a male gonad or vice versa.
Color manifestations of sex’s change
There are different manifestations in the change of sex in fish like a change of coloration, shape or size. One of these manifestations is the change of color, which is also due to secretion of hormones produced by the endocrine system. Some fish change of color when they change of sex. For example the female fish of thecoris julis are hermaphrodites when they are young and they become males when they are adults. They change their brown spine and transversal line to more showy colors like green or orange. Also the fish parrot Scarus altipinnis goes through three phases to change their sex with three different colorations from faded as colors to brilliant colors like green, blue and yellow. At first they are at...