Bloody Red Shrimp

Bloody Red Shrimp - An Invasive Species in the Great Lakes Now Found in the St. Lawrence River
The bloody red shrimp (Hemimysis anomala) has invaded all of the Great Lakes except for Lake Superior. Sampling shows the highest numbers in Canadian waters are in the Port of Montréal.  Given its high level of activity, the port could represent a key source of Hemimysis moving into other locations in and out of the Great Lakes.

Montréal Harbour offers adequate habitat and is an important location for species monitoring. Sampling in 2009 and 2010 by Environment Canada showed very high-density swarms (above 1000 individuals per m2) of the shrimp at night in sheltered sites in the Port of Montréal. Lower densities (less than 5 individuals per m2) were reported in more exposed harbour sites along the river mainstream. Daytime collections did not result in any of the shrimp in the samples and the species was virtually absent at non-harbour sites in the St. Lawrence River near Montréal.

Five sampling surveys are underway (May to November 2011) in the St. Lawrence River, Lake Ontario and Lake Erie. Samples will be analyzed to elucidate the trophic position of this new invader in the food web and its potential impact on contaminants transfer. This species is potentially a new prey item for fish juveniles and adult planktivorous fish, such as alewife or lake whitefish, whose production may be enhanced in the future.