The invasive mysid Hemimysis anomala: an up-to-date review of its biology, ecology, distribution and ecological impacts

The “bloody-red shrimp” species Hemimysis anomala , native to the Ponto-Caspian Region, has spread rapidly and adapted over recent decades to new aquatic ecosystems worldwide, causing many ecological alterations. The reported impacts associated with this invasion are numerous, including overall food web structure modifications. This review focuses on H. anomala , examining its biology, ecology, distribution and ecological impacts. The species’ rapid success is attributed to its high fecundity, fast growth rates and broad adaptability to various habitats. Recent observations suggest that its distribution may expand further, especially in Western European lakes, reservoirs and the Laurentian Great Lakes. We present insights into its habitat, seasonal dynamics and influence on trophic interactions within native zooplankton communities. Additionally, we discuss methods used to study H. anomala , including citizen-science initiatives that enhance data collection and community engagement. The objective of this research is to provide up-to-date pieces of information on H. anomala ’s ecology, including new data on its habitat preferences collected through scientific diving and participatory research. By characterising the spatial and temporal variation in its occurrence and abundance, we identify key environmental and biotic factors that may limit or support its further spread. We also highlight knowledge gaps and research priorities for future studies to better assess its impacts on the food webs of invaded ecosystems.