Abstract
Salinity tolerance and osmotic regulation were studied using two mytilid bivalves:Limnoperna fortunei fortunei, a freshwater species, and L. fortunei kikuchii, a brackish water species.L. fortunei fortunei tolerated rather lower salinity levels, 0-3%, while L. fortunei kikuchii, euryhaline species, survived in 0-30%. In media with concentrations of >3%, hemolymph osmolalities of L. fortunei kikuchii increased; at lower salinities, this species was a hyperosmotic regulator. The concentrations of Na, Mg, Ca, K, NPN and ammonia in hemolymph were also increased at lower salinity levels. These results suggest that L. fortunei kikuchii has osmoregulative ability.
