Salinity Tolerances of Native and Non-Native Crayfishes from Near-Coastal Habitats in South Carolina, USA

Abstract Many freshwater ecosystems are at risk due to the detrimental impacts of increasing salinity. This is particularly true for coastal freshwater wetlands where increasing tropical cyclone intensity and sea level rise are threatening these habitats. Little is known, however, about salinity tolerances of many coastal freshwater species. The hammock crayfish, Procambarus lunzi (Hobbs), for example, inhabits coastal hammock islands and maritime forested wetlands in South Carolina, USA. Procambarus lunzi and other native crayfish are also at risk due to invasion by the red swamp crayfish, Procambarus clarkii (Girard), a species with a high salinity tolerance. The objective of this study was to document P. lunzi’s response to chronic salinization under field conditions and to test acute salinity tolerances of two native and one invasive crayfish species under experimental conditions. Under field conditions, monthly sampling of a mesohaline wetland (range: 0.5-6.1 psu) revealed the presence of P. lunzi throughout the year. Seven-day experimental trials on acute tolerance revealed high survival probabilities (>50%) of all three species at 30 psu. These results show high acute salinity tolerance for multiple crayfish species, but some indications that chronic salinization may be detrimental, demonstrating that salinization and non-native species may threaten coastal biodiversity.