Estimation of Population Parameters of Glossogobius giuris in the Rabnabad Channel, Southern Bangladesh: Implications for Sustainable Management

The tank goby Glossogobius giuris is a commercially important dominant fish species in the Rabnabad Channel in southern Bangladesh. However, information on the population parameters of this species is not available to support its sustainable management. Therefore, the present study was undertaken to estimate the population parameters to understand both the current status and yield, and to suggest sustainable management measures for this species, using monthly samples collected from September 2021 to August 2022. Our results showed that the size of this species at first sexual maturity was 8.5 cm in total length (TL). The gonadosomatic index indicated a prolonged spawning season, with three peaks in January-February (minor peak), April-May (minor peak), and August-November (major peak). Recruitment occurred at similar to 8.2 cm TL for an extended period of the year with three pulses in March (major pulse), May-June (minor pulse), and December (minor pulse). The von Bertalanffy growth parameters were TL infinity = 25.0 cm and K = 1.10 year(-1). The growth performance index and longevity were 2.84 and 2.7 years, respectively. The estimated fishing, natural, and total mortalities were 0.42, 2.00, and 2.42 year(-1), respectively. Therefore, the exploitation rate was 0.17, and the maximum sustainable yield was 0.37, indicating that the stock of G. giuris was not subjected to overexploitation. Hence, management intervention is not needed at this moment. Rather, a substantial amount of fishing pressure could be increased to obtain the maximum benefit.

Automated summary

This study estimated the population parameters of the tank goby Glossogobius giuris in the Rabnabad Channel and suggested sustainable management measures. The size at first sexual maturity was 8.5 cm TL. The species had a prolonged spawning season with three peaks and recruitment occurred at 8.2 cm TL with three pulses. The growth parameters, mortality rates, and exploitation rate indicated that the stock of G. giuris was not overexploited and could tolerate increased fishing pressure for maximum benefit.