Respiratory responses to salinity, temperature and hypoxia of six caridean shrimps from different aquatic habitats

The respiratory response of six caridean shrimp species under different salinity and dissolved oxygen concentrations (DO) has been carried out at 20 and 25 °C. The lowest mean specific oxygen consumption rates (MO2) were found for the less active benthic crangonids Crangon crangon and Philocheras monacanthus; whereas the highest ones corresponded to the two more mobile native palaemonids Palaemon longirostris and Palaemonetes varians. The level of oxygen regulation displayed by the different native species was mainly related with environmental characteristics of their common habitats: species with temporal (C. crangon) or permanent (P. varians) estuarine habitats tended to be more tolerant of salinity changes and/or hypoxia, than are fully marine (P. monacanthus) or freshwater (Atyaephyra desmarestii) species. The estuarine P. longirostris showed moderate oxygen independence, but rather independent of salinity and temperature fluctuations. The exotic shrimp P. macrodactylus seemed to have higher tolerance to hypoxia that its native counterpart P. longirostris at brackish waters, but only under moderate temperature (at 20 °C). Results of this study suggest that a simultaneous evaluation of respiration rates and their dependence on DO could be an integrative way of determining the potential effects of increased salinity, temperature and hypoxia on aquatic species with different mobility and/or from different habitats.