Temporal Variation of Relative Growth Pattern and Condition of Glossogobius giuris (Hamilton, 1822) in the Garai River, SW Bangladesh

The present study designates the length-frequency distributions (LFDs), temporal variations of relative growth pattern and relative condition factor (KR) of the Glossogobius giuris, which are evidently lacking in the literature. Sampling was done in the Garai River, southwestern Bangladesh using traditional fishing gears (Doar and Cast net) from March 2016 to February 2017. Total length (TL) was measured by digital slide calipers, while individual body weight (BW) was determined using digital electronic balance. A total of 972 specimens (male = 446, female = 526) ranging from 3.4 to 28.0 cm TL and 0.3 to 212.0 g BW were analyzed in this study. The LFDs showed that the 6.99 – 9.99 cm TL size group was dominant for both sexes, constituted 46% for males and 41% for females of its population, respectively. The allometric coefficient (b) values were 2.89 for males and 2.92 for females, which indicated that the relative growth pattern was negative allometric (b< 3.00) in both sexes. The LWRs were significantly different between males and females (ANCOVA, p < 0.001). Minimum value of KR was found in April and maximum value in December for male. For the female, minimum value was found in January and maximum value in December. The KR were not significantly different between males and females (ANCOVA, p=0.9745). These results will help further studies on the population assessment as well as stock assessment of the G. giuris. Furthermore, this research has established a strong base for monitoring the biological changes of this important species due to high fishing pressure, climate changes or other reasons within the Garai River ecosystem or elsewhere.