Marisia - Maros Megyei Múzeum Évkönyve 29-30/2. (2010)
Zoology
Gabriela GRIGORAS _________________________________2— Tab. 3: The Condition Factor in relation with the weight in genuine grass carp juvenile, Ctenopharyngodon idella (Valenciennes, 1844) (Kirpicinikov & Berg quoted by Nikolski, G., V., (1962) [13] Body weight (g)____________> 25________________15-25________________< 15________ Condition Factor, К________2,5-2.6________________2J__________________2J)________ Georgescu, R. and others (1991) [6] note the next values of the Condition Factor for some cyprinids species as index of good physiological state reached before the cold season: 2.2— 3.15 in common carp, 1.22-1.9 in silver carp, 1.34—1.63 in grass carp. Gheracopol, O. (1971) [7] assessed the variation of the Condition Factor in common carp juvenile under wintering conditions as is shown in table 4. Tab. 4: The Condition Factor dynamic in relation with the weight in two juvenile common carp races (Cyprinus carpio Linnaeus, 1758) (Gheracopol, O., 1971) [7] _______Common carp - Lausitz race______________Common carp - Galitia race_______ Biometric index Autumn Spring Modification Autumn Spring Modification degree degree Fulton Factor ____3.53________2.95_________14.43_______3.41_________3.19_________6.45_____ Weight (g) 50.65 43.25 14.61 48.49 42.88 11.57' There is not yet an agreement referring to the ways by which data are gathered for Condition factor calculation. An old method uses the formula К = W/L3 for Condition Index assessment. Several authors [8, 9] discuss, however the method’s employment and conclude it does not permit the comparison of results obtained from individuals with distinct sizes, because the use of the exponent 3 (the coefficient b = 3.0 corresponds to izometric growing) is not a real representation of the length and weight relationship for the great majority of fish species, the fish condition shows a variation in function of their length. As an alternative, the greater part of the cited authors propose the use of Allometric Condition factor by means of the expression К = W/Lb. Some of the authors estimate this coefficient from only one equation which links all the analysed individuals from the subsamples [2, 3, 14]. Others calculate a b value to each subsample, separating, for instance individuals catched in distinct seasons [5] or distinct genders [1]. In connection with the subject of present paper regarding the assessment of the juvenile cyprinids condition state under seasonal factors influence, significant are the results obtained by Lima-Jr, S., E., (2002) [9]. By calculating the Allometric Condition Factor of the fish with the same length range from the distinct seasons, there is a directly proportional relationship between К and weight. Consequently, the higher is the weight of individuals with the same length, the higher would be their Condition Factor. From such concept, since individuals in a sample show no statistically distinct length, the Condition Factor variation should follow the weight variation of these individuals. But the weight/length relationship can show a positive or negative allometric grow. The results cited in the scientific literature [9] shows that by applying two different methods for Fulton Factor assessment (based both on constant b coefficient, calculated for all individuals from the samples collected during on four seasons and variable b coefficient, calculated for each subsample that is seasonally extracted), it can see the predicted results of weight/length relationship for the first method and distorted values for the 2nd method. In this paper, it analyzed the distortions induced by the different calculating methods of b coefficient corresponding to the fish sampled during the experiments. 86
