Filtration rates of the green-lipped mussel Perna viridis (Linnaeus, 1758) exposed to high concentration of suspended particles

High suspended loading is one of the environmental stressors which could affect survival rates and feeding activities of marine bivalves especially the coastal species. Therefore, this study aimed to examine the effects of suspended particles (SP) on filtration rates of the green-lipped mussel Perna viridis, which is a commercial bivalve species in Thai coastal waters. The large and small mussels were subjected to 250 mg and 500 mg of SP/l, and a control treatment (0 mg of SP/l) in the experimental laboratory. Filtration rates of the mussels were measured at day 0, day 15, and day 20 after the exposure to SP. The results showed that filtration rates of two class-sizes of the mussels significantly decreased after the exposure to SP for 15 and 20 days. Before the exposure to SP (day 0), the large mussels had significantly greater filtration rates than the smaller individuals, indicating the size-dependent effects. Filtration rates of the mussels decreased with increasing concentrations of SP. Gill abnormalities, e.g., loss of cilia on the gill lamella, were detected in the selected mussels at 500 mg of SP/l. The small mussels exhibited less capability in maintaining filtration rates compared with the larger mussels under high SP concentration. Moreover, changes in filtration rates over the exposure time were also discussed based in our study. Overall, the results can reflect deleterious effects of high SP on the mussels, particularly in filter-feeding activities. These findings could raise environmental concerns over high SP that could damage cultured mussels and coastal ecosystems.