Hemimysis anomala
The “bloody-red shrimp” Hemimysis anomala, is a new aquatic invader first reported in the Great Lakes from samples collected in Muskegon, Michigan in November of 2006. It is a small shrimp-like crustacean (order Mysidacea) native to the low-salinity margins of the Black Sea, the Azov Sea and the eastern Caspian Sea and most likely was brought into the Great Lakes via ballast tanks. Mysids are also used by aquarists as a high-nutrition food for aquarium fish, although we have not found any records that Hemimysis is used this way. Mysids are often called opossum shrimp because females typically carry their eggs in a pouch. These Mysids are free-swimming when not resting on the bottom or other surfaces and have eight pairs of legs rather than the five typically found on larger shrimps and other decapods. This species appears to have established multiple reproducing populations in the Great Lakes. The impact of this species on the Great Lakes is yet unknown, but based on its history of invasion across Europe, significant impacts are possible.
Photo Credit: Photo Credits: NOAA, Great Lakes Environmental Research Laboratory.
The NOAA National Center for Research on Aquatic Invasive Species (NCRAIS) is coordinating a rapid research response to define the range, distribution, and impact of Hemimysis anomala in the Great Lakes. Help is needed to document and prevent the spread of this species! Hemimysis anomala is difficult to locate because it is nocturnal, preferring to hide in rocky cracks and crevices near the bottom along the shoreline during daylight. This species sometimes exhibits swarming behavior, especially in late summer, forming small dense reddish-tinged clouds containing thousands of individuals concentrated in one location and visible just below the waters surface in a shallow zone. This is the basis for a new survey and monitoring program being established which is asking for public assistance in locating other occurrences of this organism. Click here (Hemimysis Survey and Monitoring Network) for information about how to participate and report your observations.
For more information: [Brochure] [Scientific Factsheet]