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cercopagis pengoi invades lake ontario fact sheet: october 1999
Ontario Federation of Anglers and Hunters


Actual size = 1cm.

credit: Ontario Federation of Anglers and Hunters

Cercopagis pengoi is a tiny member of a large group of organisms called crustaceans which includes species like crayfish and shrimp. It is also a relative of the spiny water flea which was introduced to the Great Lakes in the 1980s. Originating from the Caspian Sea in Eastern Europe, Cercopagis has invaded lakes in Finland and Russia, and was discovered in Lake Ontario in August 1998. Its most probable route of introduction to the Great Lakes was via the ballast water of ocean crossing ships.

Cercopagis is a tiny organism that is only about 1 cm in length. Cercopagis like its relative the spiny water flea, has a long spiny tail. This tail comprises almost 80 percent of its body length. Using a microscope it is possible to identify Cercopagis by a unique loop at the end of its tail, as well as a pointed brood pouch which may contain eggs. To the casual observer however, these characteristics are unlikely to be seen.

Anglers are most likely to encounter Cercopagis on their fishing lines in clumps of hundreds of individuals. The long spiny tail of Cercopagis can become entangled on fishing lines, creating havoc for anglers as the first line guide of their fishing rod becomes clogged with hundreds of Cercopagis. Anglers have reported having to cut their lines because they are unable to reel them in. These masses of individuals look and feel like wet cotton batten. Tiny black dots in these masses are the single eyes of each individual.

Confirmed reports of Cercopagis have been limited to Lake Ontario, Lake Michigan and several inland lakes in New York State. It is likely that Cercopagis will spread to the other Great Lakes. We are seeking the public╠s help in reporting other locations where this organism is found.

Cercopagis feeds on tiny aquatic organisms called zooplankton which are also an important food source for fish and invertebrates, especially juvenile fishes.

Although it is too early to verify the impacts that Cercopagis may have on the Great Lakes ecosystem, scientists are concerned that its high reproductive rate will lead to high densities of this crustacean. Cercopagis can produce up to 13 offspring at one time, reproduce numerous times in one season, and produce "resting eggs" which can remain dormant over the winter. Potential ecological impacts of this new introduction could include the decline of native zooplankton species when Cercopagis numbers become high. As a consumer of zooplankton, Cercopagis could affect not only juvenile and small fish populations but also larger fish that feed on these smaller fish. In addition, it is believed that smaller fish will be unable to eat Cercopagis due to its long spiny tail as has been the case with spiny water flea. More research is vital to determine the full impact of Cercopagis on the biodiversity and ecology of our lake ecosystems. In Lake Ontario, Cercopagis has already had detrimental effects on recreational anglers and charter boat operations. In addition, the commercial fishing industry could be impacted if Cercopagis fouls fishing nets.

Although Cercopagis has become established in several parts of Lake Ontario, its spread can be prevented or slowed to other Great Lakes and our inland lakes. Please take the following precautions to help prevent the spread of Cercopagis and other exotic species.

Inspect your boat, trailer and boating equipment and remove any visible plants or animals before leaving any waterbody.
Drain water from motor, live well, bilge and transom wells while on land before leaving the waterbody.
Empty your bait bucket on land before leaving the waterbody. Never release live bait into a waterbody, or release animals from one waterbody into another.
Wash/Dry your boat and equipment to kill harmful species that were not seen at the boat launch. Some species can survive for several days out of water, so it is important to:
  • rinse your boat and equipment with hot tap water (>40 C); or
  • spray your boat and equipment with high pressure water (250 psi); or
  • dry your boat and equipment for at least five days, before transporting to another waterbody.

is native to the Caspian Sea.
However, the invader spread within Europe and then to North America.

visit our seiche article Our Lake Has Fleas


Other exotic species pages:

AIS: An Educator's Information and Materials Guide (PDF download)
A Field Guide to Aquatic Exotic Plants and Animals
Eurasian Watermilfoil Factsheet
Eurasian Watermilfoil ID Card
Exotic Aquatics Traveling Trunk
Exotic Flowering Rush
Exotics To Go! CD
Fishhook Waterflea
Is it a White Bass or a White Perch
Purple Loosestrife ID Card
Purple Loosestrife: What You Should Know, What You Can Do
Round Goby ID Card
Round Gobies Invade North America
Ruffe: A New Threat to our Fisheries
Ruffe ID Card
Rusty Crayfish: A Nasty Invader
Sea Grant Nonindigenous Species Compact Disk Information
Sea Lamprey: The Battle Continues
Spiny Tailed Bythotrephes
Three-State Exotic Species Boater Survey
Threespine Stickleback
Zebra Mussel ID Card
Zebra Mussel Overview

Related Seiche articles:

One Million Exotics ID Cards Available!
Aquatic Exotics: Highlights of the Ninth International Zebra
    Mussel and Aquatic Nuisance Species Conference
Ballast Water Filtering Project Comes to Minnesota
"Bone-Cold Café" Suits Ruffe
Escaping Classroom Routines with Exotic Species
Exotics To Go! Presentations and Publications to Prevent the Spread of Aquatic Nuisance Species
Force of 3 to Cooperate on ANS, Food Web,
    and Fisheries Issues
Giving Exotic Species a Taste of Their Own Medicine
Goby Population Found in Duluth-Superior Harbor
Habitattitude™ Hopes to Stem Releases of Aquatic Plants and Fish
Highschoolers Write about Eurasian Species
Invasive Aquatic Plant Field Guide
Invasive Crayfish Discovered in St. Louis Bay
Lake Superior's Native Lampreys
Mail-Ordering Aquatic Plants Can Be Dangerous
Major Zebra Mussel Infestation in Harbor Impacts
    Native Mussels, Boaters
Marketing Lamprey in Europe: A Good News/
    Bad News Story
New Exotic Species Projects Funded
Our Lake Has Fleas
Preparing for Purple Eaters
Romancing the Sea Lamprey (Love Potion Number 3KPZS)
Ruffe Bibliography Available
The Smell of Fear: Ruffe "Alarm" Pheromones
Tubenose Goby "Leaps" to Duluth/Superior
Two Exotic Species Projects Funded
Water Gardeners and Businesses Concerned about Invaders
Where Have All the Purple Flowers Gone?
Workshops Benefit from New Training Video
Zebra Mussels "Pulse" in Duluth-Superior Harbor
return to the exotic species index
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 www.seagrant.umn.edu/exotics/fishhook.html modified January 26, 2010