The spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) as an inhabitant of the Baltic Sea — experimental evidences for its invasion of brackish waters

The main aim of the present study was to determine the effect of low salinity conditions (3 PSU and 7 PSU) on the hatching success, growth and mortality of Orconectes limosus. The results revealed that berried females survived exposure to salinities of 3 PSU and 7 PSU whilst incubating their eggs. The reproductive success reached 100% at both salinities. The length increment of young crayfish per molt was larger at 7 PSU than at 3 PSU — but their condition was affected by higher salinity. The mortality among juveniles reached approximately 50% within 5 weeks of hatching at both salinities.