|
Higgins'
Eye Mussel Restoration
|
|
|
Photo
courtesy of Illinois Natural History Survey, Labels
by Doug Betz
|
Biology:
Glochidia, larval stages of the mussel, are released
by the female and must attach to the gills of the host
fish before dropping off several weeks later. Higgins’ eye provide cover for many aquatic species, provide
food for fish and mammals, and help biologists monitor
aquatic health of rivers.
Diagram
courtesy of North Carolina Freshwater Mussels
Distribution:
Historically, Higgins’ eye were found in the Mississippi
River in Pool 24 Louisiana, MO to Pool 3 Prescott, WI,
as well as in several tributaries such as the Kankakee,
Sangamon Rock and Illinois rivers in IL, the Cedar,
Wapsipinicon and Iowa rivers in IA, and the St. Croix,
Wisconsin and Black rivers in WI. The best bed was in
Pool 10 near Prairie du Chien, WI in the East Channel.
Presently,
the species is limited to sites between Pool 22 near
Hannibal, MO and Pool 7 in the Mississippi River and
the St. Croix, Wisconsin and Rock rivers.
Higgins’
eye generally live in medium to large rivers with high
current velocity in a sand-mud-gravel substrate and
are host specific. Fish hosts of the Higgins’ eye
include sauger, walleye, freshwater drum, smallmouth
and largemouth bass.
Reasons
for Decline:
Higgins’ eye were never common, but alteration
of their habitat such as impoundment, dredging and increased
turbidity and sedimentation probably decreased their
range and abundance. The greatest threat to their existence
occurred in the 1980’s with the introduction of
zebra mussels. This invasive species competes for food
and oxygen and can attach to the shells of native species
in large numbers.
 Reasons
for hope:
Genoa NFH propagates the Higgins’ eye each spring
by having divers collect gravid females; biologists
then remove the glochidia from the mussels; and fish
are infected with glochidia. The fish are released directly
into the river or are held in underwater cages over
suitable habitat. These artificially propagated Higgins’ eye are restoring populations in Pools 1-4 and 11 of
the Mississippi River and the Black, Wisconsin, Iowa,
Wapsipinicon, and Cedar rivers.
Mussel
Restoration photo essay.
Into
the outdoors TV program on Higgins' Eye mussels.
Guide
to Freshwater Mussels.
Freshwater
Mussels of the Upper Mississippi River System
The
point of contact for this project is:
Pam Thiel Pam_Thiel@fws.gov
(608) 783-8431
or or Mark_Steingraeber@fws.gov
(608) 783-8436
|
