Funded by: Bangladesh Agricultural University Research System, Bangladesh Agricultural University, Mymensingh, Bangladesh

Project Period: 2018-2020

Project Description:

Oxygen is one of the most important constituents for energy and metabolism of air breathing organisms. For aquatic organisms, oxygen is more critical a factor since it should be dissolved in water at a sufficient concentration for comfortable water-breathing (Dejours, 1975). Therefore, hypoxia in aquatic habitats has become a natural event and occurs when oxygen consumption rate in water (respiration, decomposition, etc. by aquatic organisms) exceeds rate of oxygen production (Graham, 1990). Hypoxia in both freshwater and marine ecosystems has become common all over the world because of growing amount of anthropogenic nutrient and organic loading in natural waterbodies (Gray et al., 2002). Many commercially and ecologically important benthic organisms like mussels and oysters are one of the most affected aquatic communities to hypoxia since eutrophication can result in serious oxygen depletion in bottom of aquatic waterbodies (Jørgensen, 1996).
Freshwater Pearl Mussel Lamellidens marginalis is one of the most preferred freshwater bivalves utilized as food by many ethnic groups in Bangladesh, Nepal and India. Excessive exploitation, loss of habitat, aquatic pollution are some of the threats identified for decline in natural population of this important species in water of Bangladesh and other Gangetic plain (Madhyastha et al., 2010). For more than a decade, Bangladesh Fisheries Research Institute (BFRI) has been trying to develop pearl culture in freshwater utilizing this species (Hossain et al., 2004). Therefore, this species requires special attention with regard to its growing economic importance and due to suitability of this species to culture in open fresh waterbodies. While freshwater pearl mussel is cultivable in open freshwaters like ‘haor’ and ‘beel’ wetlands and as well as in bound waters like ponds and ‘baors’, its potential risks of being stressed by hypoxia due to ehtrophication from agriculture and domestic swages should also be considered and studied.
Broad objective: A detailed understanding on how hypoxia in fresh waterbodies due to anthropogenic activities can stress growth, survival and other physiological factors in freshwater pearl mussel L. marginalis.
Specific objectives:

(i) To study growth and survival of freshwater pearl mussel exposed to hypoxia;

(ii) To observe development of reproductive organs of pearl mussel in hypoxic waters;

(iii) To examine whether hypoxia is capable of affecting hatching & spawn survival and can cause developmental deformities; and

(iv) To investigate physiological alterations in different internal organs of pearl mussel exposed to hypoxia.