Please have a look at this researchgate link also.

https://www.researchgate.net/post/What_is_the_physiological_definition_of_sexual_maturity_in_fish/1

Please check this useful link also.

https://www.researchgate.net/post/Are_there_simple_and_non-invasive_tests_for_the_maturity_status_of_fish/1

Kindly check..

https://www.researchgate.net/post/What_is_the_physiological_definition_of_sexual_maturity_in_fish

See also..

http://www.fishbase.org/manual/fishbasethe_maturity_table.htm

Check here too..

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132000000400014

Please see through this also..

http://www.tandfonline.com/doi/full/10.1080/19425120.2011.555724

More info..

https://en.wikipedia.org/wiki/Fish_reproduction

Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood. In humans, the process of sexually maturation is termed puberty. ... It may also be accompanied by a growth spurt or other physical changes which distinguish the immature organism from its adult form.sexual maturation" to describe the physiological process from puberty to spawning. This is a complex, continuous process, including e.g. endogenous and exogenous vitellogenesis in females, and by looking at gonadal development, one can define stages of sexual maturation.

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