| In this study, the retention efficiency (RE) of Meretrix meretrix, Mercenaria mercenaria, and Ruditapes philippinarum were measured by adding sediment or unicellular algae to adjust the concentration of suspended particles. The results showed that in natural seawater, the RE of M. meretrix, M. mercenaria, and R. philippinarum reached maximum retention when the particle sizes were 8 μm, 6 μm, and 6 μm, which were 51.1%, 59.6%, and 62.6%, respectively. With an increase in particle number concentration, the minimum particle sizes for maximal retention in M. meretrix shifted to approximately 9 μm, 13 μm, and 14 μm in low (4.32×107 cells/L), mid (5.27×107 cells/L) and high (6.65×107 cells/L) particle number concentration, respectively. The relative standardized RE decreased to 49.7%, 33.4%, and 26.2%. As in M. meretrix, the minimum particle sizes for maximal retention in R. philippinarum shifted from 6 μm to 9 μm, 12 μm, and 14 μm with the change in particle number concentration, but the change in maximal retention was not significant. The change in maximal retention in M. mercenaria was not significant; however, the minimum particle sizes for maximal retention shifted to approximately 8 μm, 9 μm, and 10 μm, respectively. With the increase in particle concentration, the change in maximal retention and minimum particle size for maximal retention was not significant in three different particle concentration, low (5.7 mg/L), mid (11.8 mg/L) and high (23.3 mg/L), retention of M. mercenaria changed significantly, 60.7%, 27.6%, and 25.5%, respectively. The results indicate that the RE of M. meretrix and R. philippinarum were more sensitive to particle concentration, while the RE of M. mercenaria was more sensitive to organic content. |
