abstract:We measured concentrations of Ca2+ in tissues (hemolymph, hepatopancreas, cuticle, and muscle) of the whiteleg shrimp Litopenaeus vannamei (Boone, 1931) and recorded changes in tissue calcium levels at molting stages and different salinities. Calcium in tissues varied significantly with molting stage (p < 0.05). Salinity also affected Ca2+ concentrations in tissues (p < 0.05). The highest Ca2+ concentrations were found in the cuticle, followed by the hepatopancreas. Ratios of Ca2+/Na+ in tissues (except for muscle) varied with the molting stage and were higher in 4 g L-1 than in other salinities. Calcium entering the shrimp may initially be mineralized in the cuticle or stored in the hemolymph and hepatopancreas, after which it is released to support mineralization in the post-molt period. Muscles may take part in the growth of L. vannamei by storing calcium during the molting cycle.