COMPARISON OF RELATIVE GROWTH OF ORGANS, PARTS AND PROCESSING YIELD COMPOSITION IN TWO SPECIES OF CHINESE CARP

During the present study a total of 123 specimens of grass carp (Ctenopharyngodon idella) ranging from 10.7 to 54.5 cm in total length , and 11.48 to 1714.31g in wet body weight;127 specimens of silver carp (Hypophthalmichthys Molitrix) ranging from 6.6 to 52.6 cm in total length and from 2.49 to 2208.81 in wet body weight were investigated. Smaller and bigger sizes of both the species were represented by two distinctly different shapes of the fish weigh-length curves. All further analysis of followed these two phases. Accuracy of fish length measurement was observed up to 0.1cm. the sensitivity of weight measurements was upto 0.1 g and 0.0001g for fish and its organs, respectively. Growth of all the organs/parts was determined on the basis of isometry and allometry.\ud \ud Wet body weight of the species in smaller and bigger size groups was not consistent with the cube law and showed positive allometry. Residual factor was found to be highly correlated in all size groups except in smaller size of silver carp. Head weight was found to show negative allometry in all sizes except in smaller size of grass carp. Fork length, standard length, tail length showed isometry in smaller size and allometry in bigger size of both species. Gut length showed positive allometry and gut weight negative allometry with total length in both the sizes of grass carp and silver carp. Mouth dimensions in bigger size, mouth width in smaller size of grass carp and mouth gape in bigger size of silver carp also showed allometry with total length.\ud \ud Morphometric data of 24 different organs/parts indicated growth pattern with increase of body size in both the size of grass carp and silver carp. Trunk showed positive and eye ball, eye lens, brain expressed negative allometry with increase of body size in all groups in both species. Air bladder, heart, gonads and gills also showed positive allometry in bigger size groups of silver carp and isometry in grass carp. Scales were positive allometric in bigger sizes; head was isometric in smaller size and negative allometric in bigger sizes of both species except in silver carp against total length. Remaining organs showed variable growth pattern with wet body weight and total length or fish size. As a whole most of the visceral organs showed isometric or negative allometric whereas non-visceral organs showed isometric or positive allometric growth increase of fish size. Analysis of covariance was also used between the same size of different species.\ud \ud After the removal of head, all fish and viscera the remaining part of the fish was given the name as processing yield. It was observed that body constituents showed highly significant inverse correlation with percent water in all size groups except ash in bigger size group. Condition factor was found to behave differently with body size, fish species and body constituents. Body size was strongly correlated with totals mass of all the body constituents in different size groups of both the species. Smaller and bigger size of both the species showed positive allometry wit increase of fish size except in smaller size of grass carp where it was isometric. The predictive models have been developed. While comparing, different species showed non-significant different towards their constituents. Significant differences were found only n the percentages of fat and protein while bigger sizes were found to give better yield than smaller sizes. Within the name size all the constituents were uniformly distributed