Bloody Red Shrimp, Killer Shrimp and Freshwater Shrimp

Table of contents:

• Aquatic invaders
• Pathways of invasion
• Threats to the environment, the economy and society
• Focus on an invader
• What you can do

• What to do if you find aquatic invasive species?

Bloody Red Shrimp

(Hemimysis anomala)

Photo credit: S. Pothoven Great Lakes Environmental Research Laboratory

Characteristics

• females up to 1.7 cm and males up to 1 cm
• large, prominent black eyes
• square tail with 2 spines at the end
• red or orange body, partly translucent with pigmented red sports; colour varies depending on the light and water temperature

Origin

Bloody Red Shrimp is a small crustacean native to the coastal regions of the seas of central Europe. It was first intentionally dispersed in Europe between the late 1940s and the 1980s to increase fish productivity. Its dispersal has since continued via the ballast waters of ocean-going vessels. It was detected in 2006 in the Great Lakes (except Lake Superior), the St. Lawrence River in 2008, and in the Ottawa River in 2019.

Habitat

Although it can tolerate brackish waters, Bloody Red Shrimp lives mostly in fresh waters with weak or moderate currents. It is often found near docks, ships, and maritime structures, finding refuge in bottoms strewn with rocks and shells. It moves in swarms and can shift very quickly when disturbed. During the day, the Bloody Red Shrimp migrates in deep water to avoid light and rises to the surface at night to feed on insect larvae and plankton.

Similar species

Bloody Red Shrimp resembles a native shrimp found in the Great Lakes, Opossum Shrimp (Mysis diluviana). However, the tail of the Opossum Shrimp is forked. Using a magnifying glass helps to see this difference.

Opossum Shrimp

Killer Shrimp and Echinogammarus ischnus (Freshwater Shrimp) are 2 small invasive scuds (gammarids). They have the appearance of curved shrimps with laterally compressed bodies.

Characteristics

Origin

These 2 species are native to central Europe and Asia. Killer Shrimp has not yet been recorded in North America. However, E. ischnus was first observed in the Detroit River in 1994. It was introduced in the ballast waters of ocean-going vessels. Through watersports and recreational fishing, it has since spread to the Great Lakes and the St. Lawrence River.

Habitat

Killer Shrimp and E. ischnus are species found in lakes and rivers, where the current is weak or moderate. They are able to live in both fresh and brackish waters because they can tolerate large variations in temperature and salinity. They usually colonize rocky, gravelly or shell-strewn bottoms that provide shelter. E. ischnus can be found on bottoms with sand and clay, near solid surfaces like docks and submerged structures.

Similar species

The Killer Shrimp and E. ischnus resemble several native gammarids such as Gammarus fasciatus. It is very difficult to tell them apart without a microscope and, usually, only experts can do it.

Gammarus fasciatus