الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
With increasing the populations all over the world and the increase
in food demands especially for protein sources, fish are considered to be an
important and more valuable source of animal protein characterized by
high nutritional value. The fish catching from natural sources, marine and
fresh water is no longer enough to satisfy such high demands. which has
led to wide-spread and practicing of aquaculture in all countries of the
\\-orld including Egypt. To produce high quality production from fish, we
should have a full detail !cnowledge of the reproducti\e processes in fish
especially those mostly beE1g cultivated.
RPproctu~u·on in Ti + ; • roou’at?d h\· ev•ernol efl\”J”ronmontal fa~ror· ....., £ \... ! ~ ~ ~·~·· .~ ”-~ 1~ .._ .._.~ _....._L .._ ._.::...~ .._ ~._.._.._..__. .._ _,_ I... .. ~
that trigger internal mec:·.a:1isms into action. Em ironmental factors that
have been shown to play :; ;;igrrificant role in the reproductive cycle are:
photoperiod: water temper&cure and water quality !e.g .. dissolved oxygen.
pH, hardness, salinity .. Jkalinity: nutrition). The final event of the
reproductive cycle. the release of eggs and sperms resulting in spawning .
can be controlled by either placing the fish in an appropriate environment
or by changing the fish i:Jternal regulating factors by injecting fish with
hormones or other sub;,t.mces. The internal mechanisms that regulate
spawning are similar for 1~” ’t fish (Rottmann el a/ . . 1992).