Here's an article that might be of interest to mussel enthusiasts and for
those of you along the Cedar River.
Jane Clark
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DNR ATTEMPTS TO REINTRODUCE ENDANGERED MUSSEL INTO CEDAR RIVER
By Joe Wilkinson
DNR Information Specialist

Right about now, thousands of bio-hitchhikers are bailing out.  Tiny
glochidia - larval mussels no larger than grains of sand - are releasing
holds on host fish and settling to the bottom of the Cedar River.

With ideal conditions - and a whole lot of luck - a tiny fraction will
survive.  Over the next decade biologists will return, searching for growing
Higgins eye clams.

Their work here, and on tributaries of the Mississippi River, is a long
shot, but perhaps the last shot for the endangered Higgins eye.

The effort mixes tradition with experiment.  Studies pointed researchers to
the gravelly riverbed below the limestone bluffs, the palisades that give
Palisades-Kepler State Park its name.

"It gets down to why save any species.  There is untold genetic makeup that
might be lost," said Scott Gritters, fisheries biologist with the Iowa
Department of Natural Resources.

"Mussels are valuable biofilters.  This stretch of the Cedar River has a
history of Higgins eye and related species.  We are conducting different
experiments now to see what works."

The we includes the Iowa and Wisconsin DNR, the U.S. Fish & Wildlife Service
and the Army Corps of Engineers.  At two locations around Palisades-Kepler
State Park this month, crews released 793 smallmouth bass and 405 walleyes.
Attached to the inner gills of each fish were 150 to 200 glochidia, not
quite ½ a millimeter wide.

In nature, a female mussel will expel larvae into the face of the host fish
as it approaches.  After four to six weeks, they drop from their hosts,
hopefully into suitable locations where they will anchor themselves to the
bottom and grow.

To help that process along, biologists have cultured the endangered mussels
and actually inoculated them into the gills of the fish in the Fish &
Wildlife Service Hatchery at Genoa, Wis.

"We duplicate water conditions.  We learn, for instance, how many larvae
each fish can tolerate," said Wisconsin DNR biologist Kurt Welke.  If they
inject too many of the pinpoint sized larvae, they could irritate or stress
the fish.  Too few and it would be a waste of the time consuming effort that
goes into this laboratory hitchhiking routine.

Researchers use a variety of delivery methods, too.  In the fall, wild fish
from the Iowa River below Iowa City will be inoculated.  On the Wisconsin
River, inoculated fish are kept in cages over prime mussel beds.  As the
glochidia drop off, they stay close to home.

"It's like finding a needle in a haystack," said Welke.  "This way, at least
we reduce the size of the haystack; the area we search for mussels."

They are experimenting with different species of fish, different sizes of
fish, raising mussels in raceways, monitoring water temperature and
conditions.

"Fish culture has been around for centuries.  But mussel culture?  Some work
was done 100 years ago at Fairport (when Iowa mussels supported a robust
button industry), but other than that, there has been little," said Welke.

Much of their culture work now is with a similar mussel, the pocketbook
clam.

"It is a surrogate.  We can experiment, learn from mistakes and we aren't
affecting the Higgins eye.  When we learn, we might someday duplicate it."

All this, so Lampsilis higginsi doesn't disappear.  On the endangered
species list since the 1980s due to siltation and loss of rocky habitat, the
infamous zebra mussel has pushed it to the eco-brink and the dire "in
jeopardy" status.

Those zebras, accidentally introduced in the last decade by the shipping
industry, literally smother other mussels by attaching to them and
overpopulating mussel beds.

Because of that, the Corps of Engineers, with transportation responsibility
on the Great Lakes and Mississippi River system, is paying for the Higgins
eye recovery effort.

Under ideal conditions, the young mussels could be the size of quarters by
next fall.  In the meantime, a 2002 stocking is planned.

Results?  They will be several years away.  Optimistically, Gritters looks
for a colony in five years.  He realizes, though, it could be a decade.  And
as a biologist he looks beyond the obvious benefit.

"Mussels are strong in traditional walleye and smallmouth bass spawning
areas.  I can't help but think there's a symbiotic relationship there; that
they help each other survive."

In the meantime, the race for survival heats up*not just for the jeopardized
Higgins eye, but for other mussels that - quite literally - face a murky
future on Iowa rivers.

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