Aug 22, 2008

EARLY CYCLING LIFE FISH



EARLY CYCLING LIFE FISH.

Attention to processs which there are in growth early fish life represent piquancy because relating to the fish population stability in a[n territorial water. Mortalitas in the early growth of fish life generally very big where fluctuation of mortalitas have big share in determining variation [of] produce [at] annually. However this matter still need digs of furthermore research to be developed [by] its benefit. More to fishs species of tropik, a lot of which not yet been laid open.

Spawn with its sharess. Vertebrate egg, pursuant to to amount of deutoplasma ( egg yolk, etcetera) which there are in cytoplasma, can be divided [by] two ( Nelsen, 1953


a. egg of Homolecithal ( isolecithal).
this Egg faction only there are [at] mammalia. Amount of scanty deutoplasma especially in the form of fat items and biggest egg yolk in cytoplasma.

b. egg of Telolecithal.
In egg of this faction there are a number of egg yolk gathering [at] one of [the] its pole. fish of Ganoid have egg which kinds of him [is] equal to kinds of egg of amphibia which [do] not have foot/feet ( Gymnophiona) where amount of its egg yolk relative many and gather [at] one of [the] its pole. Romer ( 1955) naming egg faction that way by the name of mesolecithal. Egg [at] fish of Teleostei and Elasmobranchia its it massif. Protoplasm of this egg later will participate [at] some first bisection, its amount a few/little. Egg yolk [do] not partake in bisection processs, while growth of [its] embryo limited to cytoplasma found on pole of anima.


spawn of Ovipar which not yet fruit ( Picture 11), its exterior [is] arranged in layers by named [by] membrane [is] capsule membrane or of chorion. Below/Under chorion.terdapat again named [by] second membrane [of] membrane of vitelline. third membrane encircle egg plasma and the membrane named [by] plasma membrane. Third [of] all these membrane [of] him patch one another and [do] not there are room among others. Part of egg which there are cytoplasma usually gather [in] side upper egg which named [by] pole of anima. Undercarriage [of] him that is [at] adversative pole there are a lot of egg yolk. Polar this named [by] pole of vegetatif. In fact egg yolk [at] this fish almost fill entire/all volume of cell. Egg yolk exist in middle shares [of] its situation more condensed than egg yolk exist in part of periphery caused by cytoplasma. Beside that cytoplasma many there are [at] around core of egg. [At] chorion there are a micropyle that is a[n its pullin puncture [of] sperma into egg when happened impregnation.









( Picture 11),



If new egg [of] exit of mains body and come into contact with water there [is] two matter to happened is. First [of] membrane of chorion will escape with membrane of vitelline and form room. This room [is] named [by] room of perivitelline ( Picture 12). Entry of water into egg because of difference of pressure of osmose and of imbibisi protein found on surface of egg yolk. membrane of Vitelline represent barrier entry of water don't seep into egg.
( picture 12 )
Second process [is] ossification of membrane of chorion. needed to time ossification of membrane of chorion unegual base on ion of calsium which there are in water. According to Hoar ( 1957) egg which [is] incubated in pregnant water [of] chlorida calsium 0,0001 M, its membrane [of] him will be more ossify from [at] incubated egg [in] water refine. Ossification of this chorion will prevent the happening of impregnation of polyspermi. With existence of room of perivitelline below/under hard chorion, hence egg can make a move more free during its growth. Influence waving to position of embryo which [is] expanding very tereduksi caused by room of perivitelline that.

Impregnation In course of impregnation, spermatozoa come into egg [pass/through] hole of micropyle found on chorion. Every spermatozoa have [is] same opportunity for fruit one egg. However because place room the happening of impregnation that is meeting of egg with spermatozoa [at] fish of ovipar very big, hence opportunity of that spermatozoa to come in contact with egg in fact very small. To overcome [the] mentioned [so that/ to be] success impregnation, spermatozoa the [released] [by] its amount very [is] big compared to the amount of egg to fruit. optimum in a condition fish spermatozoa which is just [released] from body have strength to make a move in water during 1 - 2 minute.

Pursuant to to research which have been [done/conducted] by Hartman as well as by Motalenti ( Hoar, 1957), and egg of sperma which is just [released] from mains body, [releasing] chemical Iihat vitamin which useful in impregnation process. According to most literature of America, Iihat vitamin [released] by and egg of sperma named [by] Gamone. Gamone coming from egg [is] Gynamone I and of Gynamone II. Gamone coming from spermatozoa [is] Androgamone I and of Androgamone II. functioning Gynamone I to quicken to movement and draw spermatozoa of [is] same species by chemotaksis. functioning Gynamone II to collect and arrest;detain spermatozoa [at] surface of egg. Function of Androgamone I [is] to depress spermatozoa aktifitas when still stay in masculine fish genital channel. While functioning Androgamone II to make surface of charion become flabby as against from function of Gynamone II.

Relatively egg coat which have in water [is] ossifying and cannot be penetrated by spermatozoa except passing micropyle which its for like funnel. big Funnel hole located in small hole and exterior [in] interior. That hole that way the so small so that not possible (to) earn to be passed by by sperma more than one in one time. When spermatozoa come into funnel hole, that represent cork to the other and after head of spermatozoa that enter, shares its tail escape. Thereby impregnation [at] fish generally monosperma where if have entered one spermatozoa will quickly happened change [at] part of micropyle.

Even so happened impregnation of polyspermi, only one molten spermatozoa consist with the core of egg. While the other sipped by egg upon which its food. Momentary after happened impregnation, egg content rather a little a few/little because breaking of cavity of alveoli which there are in egg. With occurence [of] cavity of perivitelline more big so that fruit egg which have can perform [a] movement of giration during its growth hatch.

source : M. Ichsan Effendie, 1997
















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