Physiology and reproduction in fish

All living species of fishes existing in the world at present a wide variety of patterns of reproduction present as follow uni-sexuality bisexuality hermaphroditism and parthenogenesis. Like other vertebrates the fishes usually reproduce sexually and in a quite large number of them spermatozoa and eggs are formed in separate individuals and the gametes are expelled in the water where fertilisation occur. To increase and standardise an efficient hatchery system for producing the young fish of good quality insufficient numbers of a given species it is essential to know the details of its natural breeding. It involves the study of sexuality of a given fish sexual dimorphism reproductive cycle time season and place of reproduction. Also fecundity spawning pattern parental care and larval life history. Reproductive physiology of fish (RPF) is a vast scientific field which directly concerns a set of physiological processes essential for reproduction beginning with egg fertilisation and ending with sexual behaviour and spawning. Processes include gonad differentiation puberty male and female gametogenesi timing of reproductive cycles.