By John Bartlett
GoErie.com- Times News
Posted 09/20/2002
Bob Wellington was fishing for walleye about eight miles
northeast of Gull Point on Aug. 31 when he thought he got
lucky.
The drag was heavy as he reeled in what he thought must
be a big fish. Soon he noticed what looked like sheets of
paper hanging from his fishing line, and his rod eyelets
were clogged.
It wasn't paper, though. It was thousands of fishhook water
fleas linked together — the first confirmed sighting
of the invasive species of water fleas in local Lake Erie
waters.
Wellington took several samples to confirm his initial identification,
which proved correct.
Wellington's fish got away as he struggled with his line
and the globs of fishhook water fleas hanging from it.
"I decided right then I didn't like them," said Wellington,
an aquatic biologist with the Erie County Department of
Health. "I knew they could be a real nuisance, but they
were much worse than I expected. They are worse than the
spiny water flea by 10 times at least."
The fishhook water flea is native to Eastern Europe, and
first reached the Great Lakes in 1998 when it was first
discovered in Lake Ontario, presumably having hitched a
ride in the ballast water of an ocean-going ship.
It was found in Lake Michigan a year later.
It reached Lake Erie in 2001 when Igor Grigorovich, an exotic
species researcher at the University of Windsor, Ontario,
Canada, found it in the lake's western basin near the outflow
of the Detroit River.
The fishhook water fleas' spread throughout the Great Lakes
was expected, said Rochelle Sturtevant of Michigan Sea Grant.
She set up in early 2001 a monitoring program to track the
spread, location and population densities of the fishhook
water flea and its cousin, the spiny water flea, which entered
the Great Lakes in the 1980s and soon became well-established.
"(The fishhook water flea) is clearly expanding its range
in Lake Erie and the other lakes, but the reports have been
sporadic and the locations scattered," Sturtevant said.
Both the fishhook water flea and the spiny water flea are
about a centimeter long. A loop, or hook, on the end of
its long spiny tail that makes up about 80 percent of its
total length distinguishes the fishhook water flea. The
barbed-tail of the spiny water flea is without a hook. The
barbs and hooks on the tails catch, pulling the tiny creatures
into large blobs or sheets and enabling them to attach to
fishing lines.
Fishhook water fleas — Cercopagis pengoi — and
the spiny water flea — Bythotrephes cedestroemi —
are zooplankton, the group of tiny animals that help anchor
the food chain, said Chuck Murray, a Pennsylvania Fish and
Boat Commission fishery biologist.
Among the problems posed by the two invasive species is
their potential to displace native species and disrupt the
food chain. They feed on other tiny species and compete
with natives to become the dominant species, Murray said.
Some researchers are also concerned that the two invasive
species are not as nutritious as the native water fleas
and other tiny animals they are displacing. There are also
reports that small fish have trouble consuming them or don't
digest them well, Murray said.
Then there are the issues anglers have with them.
"I had a pretty decent fish on my line when I got tangled
up with them," Wellington said. "I know that sounds like
a fishy story about the big one that got away, but the fishhook
water fleas are a real pain."
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