Jumat, 15 Agustus 2008

measuring fecundity with fish length

population fecundity relative from one hundred, a thousand or ten thousand individual of certain age group. Amount of fish in every age class multiplied [by] mean fecundity of that age. Result of which [is] got from suming all age group give fecundity relative. this fecundity can differ from year to year because many individual which is not prolific annually. If in one year, there are individual in number many will cause low fecundity in the year the other.

fecundity with length.
fecundity [is] often attributed to length than weighing, because its decrease length [of] infinitesimal relatip [do] not like weight able to decrease easily. Matter which must be paid attention in making [relation/link] of fecundity with length if taking sampel which repeatedly have to take a care, because if taken fish when gonad [is] growing this matter [do] not represent growth of somatik. Become here difference there must be [among/between] growth of somatik with growth of gonad. Most [all] writer plot absolute fecundity with fish length and that [relation/link] [is]:

F = fecundity,
L = long [of] fish,
and a of b represent got konstanta of data.
The equation if [is] likened into to logarithm will get equation of straight line regresi

Log F = log a + b log L

Price Exponent of b range from 2,34 - 5,28 and most gyrating above 3 ( Bagenal, in Gerking, 1967). There [is] also making Correlation [among/between] fecundity with length by ordinary regresi later;then dites seen its correlation coefficient. Hoyt ( 1971) getting equation for the length of fish with amount of ripe egg of fish of silver jaw ( Bucata Ericymba) that is

Y = (- 1379,3 + 32,74 X )
with correlation coefficient of r = 0,89.

This correlation show strong and positive [relation/link] from both variable. Additional [of] length have correlation [to] with accretion of egg. Healy ( 1971) getting linear correlation almost [among/between] fecundity with fish length of sand goby ( Minutes pallas Gobius), but variation [of] among fish Which [is] of uniform length, fecundity different each other and its correlation coefficient lower that is r = 0,55. In investigating fish of fall fish ( Corporalis Semotilus), Reed ( 1971) getting [relation/link] [among/between] fecundity with fish length [is].

F = - 14.913,3 + 76,7 L

with correlation coefficient of r = 0,958.

Dennison and of Bulkley ( 1972) during twice accurate summer [of] potency reproduce fish of bullhead ( Ictalurus braze) [in] Clear Lake Iowa, for example getting that [there] no correlation [among/between] fecundity with body length ( Picture 7). Correlation coefficient got for year 1969, r = 0,19 and for year 1970, r = 0,09. Lowering of got correlation possible because of extreme rotation boundary of fecundity [at] [is] same size measure represent matter which [do] not habit. Batts ( 1972) getting low r [at] fish of skipjack poor (Katsuwonus Pelamis ), showing fecundity which vary [at] [is] same footage.

sumber. M. Ichsan Effendie

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