Tolerance of Paramysis lacustris and Limnomysis benedeni (Crustacea, Mysida) to sudden salinity changes: implications for ballast water treatment

In order to draw implications for ballast water management, we tested the tolerance of two Ponto-Caspian mysid species Paramysis lacustris and Limnomysis benedeni to sudden salinity changes. The naturally stenohaline P. lacustris was more susceptible to higher salinities; its mortality rate at 19 PSU was 60%, whereas exposure to 23 PSU was 100% lethal. The euryhaline L. benedeni survived in salinities of up to 19 PSU, but experienced 100% mortality at 34 PSU. The return of both mysid species to fresh water after the 24 h exposure to higher salinities did not prevent further mortality. Considering the rather high short-term salinity tolerance of both species, a salinity of at least 30 PSU should be used as an appropriate biocide.