Life-history traits and ecological characteristics of the ornamental shrimp Neocaridina denticulata (De Haan, 1844), recently introduced into the freshwater systems of Israel

Introduction rates of alien freshwater organisms are increasing worldwide. In Israel, freshwater habitats suffer from heavy anthropogenic stress resulting in numerous records of introduction to date. During 2014 a non-native caridean shrimp was found in several locations in the Jordan River system and in the Yarqon Stream. These systems represent different basins, hydrologically disconnected. Using both DNA analysis (mitochondrial genes COI and 16S) and morphological tools the species was identified as Neocaridina denticulata, an ornamental species originating from South-East Asia. Phylogenetic analyses of 56 Israeli and 18 Japanese specimens revealed no geographical differentiation among Israeli specimens, affiliated to a single haplotype, in contrast to the division of two groups within Japanese specimens. It is therefore possible that this species had been released by aquarium hobbyists. Field and laboratory observations revealed a highly reproductive and environmentally tolerant populations, reaching a reproductive stage within few months and releasing more than 70 larvae per ovigerous female. In addition, N. denticulata was found to be significantly larger in comparison to the native Atyidae shrimp Atyaephyra orientalis. We suggest that N. denticulata may expand its geographical distribution into similar freshwater systems in Europe and other Mediterranean countries, where suitable environmental conditions exist. We further provide tools for taxonomic identification and field observations for effective detection and inspection protocols.