Abstract Salinity is a critical factor which deacrease with freshwater inputs from rivers or heavy rainfall events, influencing marine bivalves living in estuaries and intertidal marine areas. Most studies on salinity influence are focused on short-term experiments, which cannot detect the effects on species when conditions are constant for extended periods. This study investigated the long-term response of the coastal bivalves Ruditapes decussatus, Ruditapes philippinarum, and Chamelea gallina exposed to different salinity treatments over 21 days.At salinities between 15 and 20 g/L, bivalve mortality shows a 'turning point', meaning, from this point there are distinct patterns in mortality, with significantly abrupt reduction of mortality when salinity is above. Beyond this point, mortality decreases significantly, although tolerance varies by species and exposure duration. After seven days of exposure, survival at low salinities (0–5 g/L) was higher in R. decussatus compared to R. philippinarum and C. gallina. At 15 g/L, mortality decreased in all species, particularly in R. decussatus, which showed full survival at 20 g/L. However, after 21 days, high mortality was observed at the lowest salinities, with R. decussatus displaying increased tolerance until 20 g/L, while R. philippinarum and C. gallina did not show reduced mortality until 25 and 30 g/L, respectively. Median Lethal Concentration analysis revealed that C. gallina had lower tolerance to prolonged hyposaline conditions. Overall, R. decussatus showed superior survival in low salinity environments, suggesting that it is more resilient to environmental fluctuations, a trait that could be critical for its conservation under climate change scenarios.
García et al. (Thu,) studied this question.
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