Trends in Relative Fecundity Estimation and its Relationship with Body Length and Weight in Himalayan Prawn Macrobrachium dayanum

摘要

Fecundity is the total no. of eggs produced by a female with reference to body weight during the average life span. The eggs were found attached to the body of the female inside the brood chamber. During the estimation of fecundity it was found that Macrobrachium dayanum spawned twice in a year (i) from May to July and (ii) Nov to Dec. It was observed that the no. of eggs spawned varied considerably with total length and body weight. The length of berried females, considered for the present study, ranged from 4.2 cm to 5.7 cm. The generalized trend as recorded during the present investigation revealed that the number of eggs showed an increasing trend (98-104) with the length increment (4.2-4.5 cm). Increasing trend of the egg number in relation to body length was in the order: 4.2 cm: 90; 4.3 cm: 99.5; 4.5 cm: 102. Following this, however, a decline is evident as the number of eggs was found to be 78 when the mean body length was 4.6 cm. The mean fecundity calculated was 50.75 ± 9.02 for the mean total body weight of 1.95 ± 0.47 g with average no. of eggs recorded as 95.6 ± 9.14. In Macrobrachium dayanum the breeding capacity ranges from 78 to 104 and increases with an increase in all the body parameters. The straight-line relationship has been observed between the fecundity and prawn length/weight. The fecundity was more dependent on body weight than the body length.