Estimation of Fecundity and Gonadosomatic Index (GSI) of Somileptes gongota (Hamilton, 1822) from the River Padma in Rajshahi District, Bangladesh

The study focused on assessing the fecundity and gonadosomatic index (GSI) of the Gongota Loach species, scientifically known as Somileptes gongota, during the period spanning from April 2019 to March 2020. The fecundity of S. gongota exhibited a range of values, spanning from 3375 to 73459.75. Out of a total of 36 specimens, 16 were identified as male while 20 were identified as female. The typical length of female specimens varies between 5.4 cm and 12.5 cm, with a corresponding body weight range of 3.72g to 19.52g. The recorded mean GSI values for the twelve-month period from April to March were as follows: 0.158, 0.231, 0.225, 0.242, 0.176, 0.00, 0.00, 0.13, 0.00, 0.00, 0.00, and 0.134. The lowest mean GSI value of 0.00 was observed during the months of September, October, December, January, and February. Conversely, the highest mean GSI value of 0.242 was recorded in the month of July. According to the monthly mean GSI of female individuals, the observed spawning season for this species spanned from April to July throughout the duration of the study, with the peak season occurring in July. The highest recorded level of fecundity was observed in the month of July, reaching a value of 73459.75. Conversely, the lowest level of fecundity was recorded in August, with a value of 3375. The study revealed a significant correlation between fecundity and body weight, as represented by the equation F=4.51BW-40115, with a coefficient of determination (r2) of 0.835. The observed fecundity values varied between 3375 and 73459.75, while the corresponding body weights ranged from 3.72g to 19.52g. The correlation between fecundity and standard length was determined to be F=0.012 SL3.628 (r2=0.794). The results of the regression analysis revealed a cubic relationship between fecundity and standard length, as well as a linear relationship between fecundity and body weight. A comprehensive understanding of fecundity and gonadosomatic index (GSI) is imperative for effective fish management.