It’s their proper name, but you can imagine that fisheries managers say it with feeling: bloody red shrimp, a.k.a Hemimysis anomala.
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| The bloody red shrimp as seen under a dissecting microscope. Photo: Courtesy of NOAA, Great Lakes Environmental Research Laboratory. |
They’re among the most recent aquatic Great Lakes invaders: binge eaters of zooplankton, which are the sustaining food of small fish, which in turn are the primary food source of our most prized commercial and recreational fish species. In other words, bloody red shrimp are a serious threat, and fisheries managers are working hard to perfect standard procedures for detecting, tracking and measuring the impact of the bloody red shrimp invasion in Lake Ontario, including:
• Testing the most efficient method for trapping the shrimp, including developing and refining zooplankton and phytoplankton nets.
• Using these collection methods to map the distribution and habitat preference of the bloody red shrimp. Densities of the shrimp in Lake Ontario can range from zero to 200 per square metre. “Clouds” of bloody red shrimp can sometimes number in the millions.
• Documenting the nature of the food webs in areas with and without the shrimp, to measure differences and to have a “before” picture from which to assess what happens when an area is invaded.
• Examining fish stomach contents to detect differences in the diets of fish in non-invaded and invaded areas. Ecological tracers are also being used to reveal linkages between prey and predators in food webs. For example, are contaminants being absorbed and moved from prey to predator?
• Monitoring the growth of algae and algae blooms. Zooplankton eat algae. If the shrimp devour zooplankton, will algae volumes increase?
• Studying fish consumption of bloody red shrimp. Researchers have discovered that so far, it is relatively low, possibly because fish are learning about this new “food” and because shrimp hide during the day and fish feed during the day, at dawn and dusk.
Click here to view a map of the project area
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About the Bloody Red Shrimp
• The bloody red shrimp is the 185th aquatic invader in the Great Lakes —another ship ballast-water hitchhiker from the Black and Caspian Sea areas of eastern Europe.
• The shrimp grow up to one centimetre in length and prefer rocky bottoms near the shore, often close to docks and retaining walls where they shelter in the shade during the day.
• The name “bloody red,” is not derogatory, but descriptive. When these tiny, omnivorous crustaceans swarm in the water – the only time they can be easily spotted – they appear as a red cloud. Loosely related to true shrimp (which are not know to swarm), these invaders were first reported in U.S. waters in Lakes Michigan and Ontario in 2006 and have now spread to the Canadian side of Lakes Ontario, Erie and Huron.
Partners:
- Fisheries and Oceans Canada
- Cornell University, Syracuse, New York
- Queen’s University, Kingston
- Ontario Power Generation
- Ontario Ministry of Natural Resources
- St. Lawrence River Institute, Cornwall
- U.S. Geological Service
For more information, contact:
- Tim Johnson, Great Lakes Research Scientist, Aquatic Research and Development Section, Ministry of Natural Resources, Picton (613) 476-7718
- Jeff Brinsmead, Invasive Species Biologist, Biodiversity Branch, Ministry of Natural Resources, Peterborough (705) 755-5424
- Alastair Mathers, Lake Ontario Canada-Ontario Agreement Basin Coordinator, Lake Ontario Management Unit, Ministry of Natural Resources, Picton (613) 476-8733