PHYSIOLOGICAL RESPONSES TO HYPER-SALINE WATERS IN NECORA PUBER (VELVET CRAB)

Abstract

Brine (hypersaline solution) is increasingly discharged into coastal areas as the result of solute mining and desalination schemes. Therefore, more information on physiological and biochemical responses of marine organisms to those solutions is needed to clarify their tolerance to salinity changes. However, this information is lacking, so the goal of the present study was to assess how velvet crab responds physiologically to such solutions. Methods: Adult crabs were placed in large, plastic tanks filled with 35 psu water, 10 crabs were removed for blood collection. At the completion of sampling, the salinity was raised to 40 psu and held at 40 psu for 4 days and 10 more crabs were sampled. This basic procedure was repeated at 50, 55 and 60 psu and there were a control group at salinity 35 for each experimental group. Results: At higher salinities (55 and 60 psu), the levels of haemolymph total proteins, glucose, lactate and total ammonia increased significantly with respect to the control groups. Moreover, at higher salinities, haemolymph ion levels rose significantly. In contrary, significant decreases ofhaemolymph pH and haemocyanin were observed at higher salinities. Conclusion: Salinity stress induced physiological and biochemical changes in the haemolymph of velvet crabs, therefore, this study gives attention to the importance of finding ways for determine the optimal dilution of hypersaline brine discharges into water to minimize any impact on its communities.