Contacts
Joanne Grady, 573-876-1909
Columbia Fish and Wildlife Management Office
Louise Mauldin, 573-876-1909
Columbia Fish and Wildlife Management Office
The subject is the pallid sturgeon
(Scaphirhynchus albus). It is a bizarre, prehistoric looking fish
found in parts of the Missouri and Mississippi rivers. Scientists
believe that its roots in these rivers extend back as much as 70
million years. Modern-day pallid sturgeons have been known to
grow up to six feet and weigh as much as 80 pounds. They are an
endangered species. The U.S. Fish and Wildlife Service is working
with many partners to bring them back.
"The pallid sturgeon was first
recognized as a species in 1905 and was listed as an endangered
species in 1990," said Joanne Grady of the U.S. Fish and
Wildlife Service's Fish and Wildlife Management Assistance Office
(FWMAO) in Columbia, Mo. "It's an ancient fish species that
evolved in turbid, free-flowing large rivers with braided
channels, sandbars and extensive backwater habitats."
Grady, the Columbia FWMAO and their
partners hope to halt and reverse declines in pallid sturgeon
populations by conserving and restoring the fish's vital habitat
on the Missouri River.
One initial part of that effort involves
long-term monitoring of several sites on the Lower Missouri River
to document impacts and benefits of Missouri River operations.
Other groups helping in this work are the Nebraska Game and Fish
Commission, the Iowa Department of Natural Resources and the
Missouri Department of Conservation.
The data that is being collected will be an
important component to state and federal decision-making
regarding modifications to Missouri River operations, mitigation
site development, habitat restoration and land acquisition.
As noted, the Missouri and Mississippi
rivers historically provided ideal habitats for the species.
However, in the Missouri and Mississippi rivers of today the fish
face habitat alteration, modifications to the rivers' natural
hydrography and hybridization of the species that has occurred
with the shovelnose sturgeon.
"Our staff has worked for the last
five years to document the occurrence and habitat preferences of
pallid sturgeon," Grady said. "This includes a
multi-state project to identify pallid sturgeon habitat and
refine capture techniques and equipment for this uncommon
fish."
From 1996 through 2000 the Columbia FWMAO
worked with the states of Nebraska, Iowa and Missouri and
Southern Illinois University to cooperatively sample pallid
sturgeon in the Lower Missouri and Middle Mississippi rivers.
"Sturgeon had last been extensively
sampled in the Lower Missouri and Middle Mississippi rivers in
the late 1970s," Grady said. "In the recent study,
sampling crews targeted river reaches in which historic pallid
sturgeon catches were noted or in which juvenile pallid sturgeon
stocked by Missouri Department of Conservation's Blind Pony
Hatchery were recaptured."
During the sampling, seven presumed-wild
pallid sturgeon and two hatchery-reared pallid sturgeon were
collected in the Lower Missouri River. Eleven hatchery-reared
pallid sturgeon and two presumed-wild fish were collected in the
Middle Mississippi River.
"Sampling documented declines in
pallid sturgeon numbers coupled with the increased hybridization
rate," Grady said, "This indicates a need to step up
efforts to benefit the species."
The most recent sample, when compared to
earlier sampling, showed that the ratio of wild pallid sturgeon
to all river sturgeon collected dropped from about 1 in about 400
in 1985, to 1 in nearly 650.
Seven pallid-shovelnose hybrids were
collected in the Middle Mississippi River while 15 were collected
in the Lower Missouri River. In this sampling, the rate of
hybridization increased from 1 in 365 in the late 1970s to 1 in
235 in the 1990s.
But there were some slight indications that
the pallid sturgeon might be holding its own in some areas of the
rivers.
The first documented evidence of natural
reproduction of the species in the lower Missouri River was
collected in August 1998. Service staff collected three larval
pallid sturgeon in an ongoing monitoring study of the Lisbon
Bottoms Unit of the Big Muddy National Fish and Wildlife Refuge
on the Lower Missouri River.
A total of 44 larval sturgeon were
collected from 1997 through 2000 in a seven-mile stretch of the
Missouri River. Three larval sturgeon were identified as pallid
sturgeon, seven were identified as probably being pallid
sturgeon, three as shovelnose sturgeon and 31 could not be
determined if they were pallid or shovelnose.
"Our staff will continue work to
provide the pallid sturgeon population information needed by
Missouri River managers and policy makers over the next several
years," Grady said. "These efforts we hope will lead to
stronger pallid sturgeon populations and continued habitat
conservation and restoration in our river systems."
NOTE TO EDITOR: Electronic
images of these fish can be obtained by contacting the U.S. Fish
and Wildlife Service Minneapolis Office of External Affairs at
612-713-5360
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