Fecundity and population.
Bagenal ( 1978) telling that beside absolute fecundity there [is] also population fecundity that is amount of all egg from all absolute fecundity [of] female fish to be prolific, that is all egg which to be [released] in one season of breeding. In this [relation/link] [of] specific age fecundity ( fecundity specific age) representing component of fecundity population. If/When known [by] structure old age from the population and amount of each its member [is] known, hence population fecundity can know.
[At] per annum unegual population fecundity. this Causes variation [of] relate to age composition, environmental factor like supply of food, density of population, territorial water temperature, dissolve oxygen, and others. Fishs which [is] life [at] less fertile territorial water [of] its egg production lower. Attempt with [gift/ giving] of rabon [at] fish of salmon, Scott in Bagenal ( 1978) getting that reduction of food cause reduction of its egg amount and [at] fish of stickleback, reduction of food result international of membikan become shorter but its egg size measure [do] not have an effect on. Water temperature influence fecundity indirectly. So also depth of water and dissolve oxygen [do] not represent resistor factor to fecundity. Environmental in a condition yang-menguntungkan egg [released] too many for one unfavourable in a condition.
According to Nikolsky ( 1969), for certain species, [at] age which different each other show fecundity which vary referring to supply of annual food. This influence happened also for [is] same fairish individual and earn also for population as a whole. Some of mentioned influence influence egg and supply of egg. Thereby clear now that fecundity [at] certain fairish fish or certain group [of] its big variation [of]. If one population in a few its amount year become very decreasing effect of arrest ( mortalitas) for example, matter this means will improve;repair supply of food for population of[is rest of. In the reality from its mentioned remains population it[him] progressively increase, while when complete still mentioned population or its big amount, its [of] small him.
A marked difference [at] fecundity from a[n generation happened also [at] [is] same fish [of] its size measure but having different fat content. Fish or fattest individual have fecundity relative or higher level absolute than thin fish. Usually fattest old fish than young fish. Also population fecundity can differ from year to year caused by fishs which [is] breeding [do] not [at] annually or him [him/ it] after some year.
new River fish become dweller of reservoiar which is just made, which [is] supply of food [at] first yrs. usually causing, many that fish quickly cook gonad [at] young and there are accretion of good fecundity [of] fecundity relative and also is absolute. But this matter [is] later;then followed by amount of prolific become to decrease so that the amount of entire/all egg [released] by fish individual become to decrease also.
Beside that fishs which [is] life [in] its river [of] him have [relation/link] highly water. If certain yrs. until high water level always, its [of] high him also, in comparison with other year which [is] its water level lower. Possible [is] same occurence earn happened also for fishs which [is] life [in] bog, because often water level of unegual bog from year to year effect of inclusion of erratic water.
Factors influencing fecundity and also miscellaneous related to that, Nikolsky ( 1969) making especial method as follows
1. Until certain age [of] that fecundity will increase downhill later;then again, fecundity relative downhill him before happened degradation of absolute fecundity [of] him. fecundity relative maximum happened [at] young fish faction. Old fishs sometime breeding [do] not every year. Individual which grow and cook quicker have dead mainstream in advance.
2. absolute fecundity or relative often become small [at] age class or fishs which [is] its amount happened, many for species having difference of food among size measure group
3. Arrangement of fecundity many in berespon to supply of food relate to egg yielded by fish which quickly its growth, fattest [of] bigger clan. Its mechanism relate to ripening of oosit and suction of egg. Increase, population fecundity earn because of maturity of gonad earlier of individual which grow quickerly.
4. Fish which its for small ripely earlier gonad and also its [of] high him possible because of food content and of predator in gross.
5. Difference of fecundity among species population which [is] life [at] condition of environment which different each other, form its migran [of] bigger him 6. fecundity accomodated automatically [pass/through] metabolism performing [a] reaction of to change of supply of food and yield the change in growth, like size measure [at] certain age and so do size measure and egg amount or inbreeding cycle amount one year.
7. Fecundity increase in performing [a] respon to repair of food [pass/through] maturity of gonad earlier that happened, adding individual maturity [at] fattest individual and lessen [among/between] breeder cycle
8. Quality of egg especially fill egg yolk base on age and supply of food and can differ from one population to other population.
source : M. Ichsan Effendie
