| 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
WHAT
ARE THEY?
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. WHERE
ARE THEY?
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 publicÌs help in reporting other locations where this organism is found. WHAT
DO THEY EAT?
Cercopagis feeds on tiny aquatic organisms called
zooplankton which are also an important food source for fish and invertebrates,
especially juvenile fishes. WHAT ARE THE IMPACTS?
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. BOATERS AND ANGLERS
- YOU CAN HELP
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.
Cercopagis
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 | 
