A comprehensive study on biological parameters of Osteobrama cotio (Hamilton, 1822): Conservation strategy

Osteobrama cotio, commonly referred to as Dhela locally, is one of the most essential sources of nourishment for humans. The present study was conducted at the Freshwater Station of the Bangladesh Fisheries Research Institute in Mymensingh to learn more regarding the sex ratio, length-weight relationship, condition factor, gonadosomatic index, and fecundity. Fish samples were taken monthly, and their total length and weight were measured and noted. Among the 310 samples of fish evaluated, 201 (64.85%) and 109 (35.15%) were found to be females and males, respectively (F: M= 1.88: 1). The chi-square test findings showed that there was no statistically significant difference between the two sexes in the sex ratio study (χ2= 0.164, df= 1, p>0.05).  It was shown that there was a substantial relationship (r2=0.76 for females, r2=0.96 for males, p<0.05) between fish fecundity and length. Positive allometric growth was observed in the length-weight relationships for both females and males (b=3.05 and 3.01, respectively; independent t-test; p<0.05). Throughout the study, the condition factor values for both sexes were more than 1, suggesting that both sexes are in excellent fitness (F=1.66 and M=1.67).  Males and females showed GSI values ranging from 0.001 to 0.33 and 0.25 to 10.96, respectively. The gonadosomatic index scores for both sexes maximum in June while minimum in November. The range of fecundity was 297 to 6529; where June having the highest egg count, while November having the lowest.