A Comparison of Stress Responses in Sea Urchins and Sea Cucumbers Exposed to Salinity and Handling Stress

Any animal that is kept in aquaculture conditions experiences stress, which can potentially have a negative impact on growth, disease resistance, and production. Sea urchins and sea cucumbers are both increasing in demand as a source of protein and marine based pharmaceuticals, which has caused a greater interest in culturing these species. While both sea urchins and sea cucumbers are valuable, it is beneficial to know which is more likely to be less susceptible to certain stressors that might be encountered in an aquaculture facility. To ascertain which of these species is more capable of resistance, the results from analysis of the hemal fluid obtained for the sea urchin Stronglocentrotus purpuratus in conditions of low salinity stress and handling stress were compared to the results obtained from the hemal fluid of the sea cucumber Parastichopus californicus kept under identical conditions. Based on the results obtained, sea urchins kept in handling and salinity stress conditions showed significantly increased stress and reduced immune responses than those kept in control conditions. Conversely, sea cucumber kept in the same stress conditions did not show any significant differences from the controls. These results could indicate that sea cucumbers are more resistant to exposure to stress than sea urchins, and are therefore likely to be more successful in an aquaculture environment