Larger and heavier individuals of the invasive shrimp Palaemon macrodactylus in the Salado River, Argentina

Different populations of caridean shrimp species exhibit intraspecific variation in their life-history traits as a response to environmental heterogeneity. Although the invasive oriental shrimp Palaemon macrodactylus has been introduced worldwide relatively little is known of the basic biology of this species. Here we tested whether some basic biological characteristics of a recently reported population in a low-salinity environment in the Salado River, Argentina, differed from those reported elsewhere (including other invaded ecosystems). Individuals from the low-salinity Salado River were longer and heavier than those from fully marine areas of Argentina as well as from other habitats worldwide. The between-location differences reported in this study provide useful information to better understand the striking intraspecific variability of this invasive species.