MORPHOLOGICAL OBSERVATION AND LENGTH-WEIGHT RELATIONSHIP OF THREATENED NONDI BALE Paragobiodon echinocephalus (Rüppell, 1830)

Abstract

The study describes the length-weight relationship, length-length relationship, condition factor and hepato-somatic index of Paragobiodon echinocephalus. Forty samples were collected from Mongla at Bagerhat, Bangladesh. Total length, standard length, body weight and liver weight were measured by standard units. The body weight showed a positively correlation with total length and standard length with the regression equation of BW = 2.05TL-9.35 (r2 = 0. 89) and BW = 2.30SL -8.55 (r2= 0.85) respectively. Total length and standard length were found highly correlated with the regression equation of SL = 1.11TL + 0.48 (r2 = 0.93). A weak positive correlation was observed between body weight and liver weight with the r2 value of 0.15. Hepato-somatic index showed very weak correlation with condition factor (r2= 0.01), indicating that the species is in an endangered condition. The b values indicated negative allometric growth pattern which ranged from 2.05 to 2.30 (b<3) for body weight with total length, standard length and hepato-somatic index & condition factor relationship. Whereas, positive allometric growth was observed in case of liver weight and body weight relationship (b= 12.41). This study suggests that necessary steps need to be taken for the improvement of physiological and ecological conditions for higher growth and better survival of P. echinocephalus.