GROWTH AND FEEDING HABITS OF SUBYEARLINGS OF GRASS CARP(CTENOPHARYNGODON IDELLUS(C. V.))

The present paper deals with the subyearlings of grass carp under culture condi-tions, concentrating on their growth and feeding habits at different stages of develop-ment. The relationship of body length (L)/age (t) falls on a straight line, but that ofweight (W)/age (t) is exponential. The regression equation of length or weight and agewas determined through calculation. Two stages are noticed in the growth of subyearling, i.e., the fast- and the slow-growing stage. The demarcation line between these two stages seems to fall around thetime when the subyearling has reached 77 mm. in length. The growth rate of the juvenileis clearly related with the transformation of its feeding habits. The general equation ofthe subyearlings, based on the measurement of 1224 individuals, can be expressed asW=0.00003186 L2.9303. Analysis of the feeding habits of the subyearlings indicates thatthe fry feeds on zooplankton exclusively, it becomes omnivorous when scales startto appear on its body surface and then when its body length exceeds 72mm., it turnsherbivorous.