Reproductive and morphometric traits of freshwater mussel Lamellidens marginalis and associated hydrology in the Ratargul freshwater Swamp Forest, Bangladesh

Abstract

A total of 300 freshwater mussels Lamellidens marginalis were sampled from the Ratargul Freshwater Swamp between December 2020 and November 2021 to investigate the relationships between length, weight, soft tissue wet parameters, sex ratio, condition indices, gonadal histology, and hydrological features of swamp forest habitat. The shell length and shell weight varied between 5.00 and 9.50 cm and 12.26–78.96 g respectively. The length at maturity Lm was recorded as 5.98 cm and the calculated value of χ2 suggested a dominant female stock at the study site (P < 0.05). The relationship between different morphometrics of Lamellidens marginalis and environmental parameters exhibits a very weak regression coefficient value (P < 0.05), suggesting a weak effect of seasonality on the growth metrics. Previtellogenic and vitellogenic oocytes were observed in the ovary, and mature spermatids were found in the testes in samples collected in the rainy season.

Keywords

• Sex ratio
• Condition indices
• Hydrological properties
• Morphometric traits
• Gonadal histology