Seasonal Abundance and Distribution of Freshwater Snails in Different Beels of Gopalganj District, Bangladesh

Abstract

In Bangladesh, there are thousands of beels (a natural deep depression) exist in different sizes. Most of these large beels have become shrunken quite considerably in recent decades. Those beels are the potential source of snails. Gopalganj district of Bangladesh has lots of beels from where people collect huge amount of Mollusca species from the time immemorial. At present, the abundance is decreasing drastically due to uncontrolled catch. The seasonal abundance and distribution of Mollusca species in selected beel areas has been studied to know the real scenario. Surveys was conducted at summer (May-June), rain (September-October) and winter (December-January) season year round based on the observations and sampling in each six points (each of 16m2 area per point) of a beel, As such six selected beels in each Upazila of Gopalganj district have been considered under study. Sampling was done with the help of Sieves (0.2 mm, 2.0 mm and 4.75 mm), Cast nets, small hand nets and hand-picking methods and count. In this study, five snail species were found throughout the survey period where Lomba shamuk (Lymnaea stagnalis) was exhibited the highest in number than others. The highest average number (600 no/16m2) of snail was found in Gopalganj sadar Upazila at rainy season and the species comprised of only lomba shamuk. In case of Chakti shamuk (Macrochlamys indica), the highest average number (519 no/16m2) was also found in Gopalganj sadar upazila at the same period. The abundance of average number of Ghecho shamuk (Lymnaea luteola) was found low for all studied Upazila and this species was totally absent in Muksudpur. These findings may help the concern authority to take proper decisions on meaningful steps. Ultimately these findings may help the nature from the extinction of Mollusca species.