Bloody red shrimp
Hemimysis is a free-swimming, shrimp-like organism that was first spotted in Ireland in 2008. It has spread very quickly into a number of lakes on the River Shannon. It is typically small, ranging from 8-16mm in length. Body colour varies from translucent / ivory-yellow to deep red. The latter colour results from pigment-containing cells in the organism’s body. Hemimysis individuals can aggregate into locally dense swarms during daylight hours, normally in the shade of piers or harbour walls. These swarms impart a distinct red colour to the water where they occur. Hemimysis is a voracious predator and will significantly reduce aquatic insect species, which represent important fish food items, if they continue to spread at the current rate.
Distribution of bloody red shrimp in Ireland
Data from Biodiversity Maps held by the National Biodiversity Data Centre www.biodiversityireland.ie 2011