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The Sea Lamprey -
With its eel-like body and round suction-cup
mouth filled with circular rows of teeth,
the half-metre long sea lamprey looks like
a creature from a horror movie. But this
monster is real, and the parasite's blood-sucking
attacks on Great Lakes fish are truly horrifying.
The lamprey wreaks its havoc by fastening
onto its prey with its teeth, rasping out
a hole with its rough tongue, and secreting
an anticoagulant to keep the wound open.
Only 1 in 7 fish survive a lamprey attack;
one lamprey can
kill up to 20 kilograms of fish in its
lifetime.
Fortunately for Lake Ontario fish -and
fishers - sea lamprey attacks now rare.
The parasites first appeared in the Lake
in the 19th century, but spread quickly
through shipping canals in the early 1900's.
By the time the sea lamprey population of
the Great Lakes reached its peak in the
1950's, fish stocks had been drastically
depleted. Scientist worked feverishly to
develop a remedy; in 1958, they discovered
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How to
Avoid Aquatic Hitchhikers
While a 30 kilogram Asian carp
isn't likely to hide in your
bait bucket, you may not notice
a few spiny water fleas attached
to your fishing line, a zebra
mussel glued to the bottom of
your boat, or a round goby swimming
in your bilge water. While most
invasive species have originated
from ocean-going vessels and
accidental release, recreational
boaters and fishers can help
to curb their spread to other
lakes and rivers.
Environment Canada advises
boaters that they should:
• Inspect their boat, motor
and other equipment and remove
any visible plant or animal.
• Drain water from the
motor, live well, bilge and
transom wells while on land.
• Wash/dry their boat,
tackle, down riggers, trailer
and other boating equipment.
• Use hot tap water, or
spray with high-pressure water,
and dry boats and equipment
for at least 5 days before entering
another body of water.
Sports fishers should:
• Empty bait buckets on
land before leaving any water
body.
• Never empty live bait
into a water body.
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that the chemical TFM was effective in
killing sea lamprey larvae in spawning streams.
Widespread lampricide application programs
were carried out, reducing sea lamprey populations
throughout the Great Lakes by 90%.
While sea lamprey populations in Lake Ontario
have been kept under control, the parasite
has recently re-emerged as a threat in the
St. Mary's River linking Lake Superior and
Lake Huron. Modern non-chemical lamprey
control measures are being applied, including
traps and the release of sterilized males.
Asian Carp: -
Will Asian carp be the next "big"
problem in Lake Ontario? The gigantic fish,
which can weight up to 60 kilograms, have
recently been found in the Chicago Ship
and Sanitary Canal that connects the Mississippi
River to Lake Michigan. The carp are thought
to be escapees from Southern U.S. fish farms,
where they were imported to control catfish
parasites.
Like an enormous aquatic vacuum cleaner,
the exotic carp (also known as silver carp),
can eat 2 to 3 times their weight in plankton
every day. If allowed to migrate to the
Great Lakes, the carp could compete aggressively
for food with juvenile game fish and bait
fish fry and fingerlings near the bottom
of the food chain.
An electrical barrier has been placed in
the Chicago canal in an effort to contain
the carp, but some biologists believe that
further measures, including noisemakers
and bubble curtains, will be needed to guarantee
the Great Lakes' safety.
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