The pallid sturgeon, Scaphirhynchus albus, inhabits open channels in large, turbid
rivers. It occurs in the Missouri River and the Mississippi River below the mouth of the
Missouri River. In these rivers, pallid sturgeon live on the bottom in strong current, but
may also be found along sand bars and in deep scour holes along wing dams. The
pallid sturgeon was designated a Federally endangered species in October, 1990
because its survival was jeopardized by over-fishing, habitat destruction, and
hybridization. Young-of-the-year (Y-O-Y) pallid sturgeon were not documented from
the wild.

On 24 July 1998, we collected a Y-O-Y pallid sturgeon from the Mississippi River at
river mile 49.5L, approximately 2.5 miles south of Cape Girardeau, Cape Girardeau
County, Missouri. The specimen, measuring 79 mm, fork length, was captured in an
experimental bottom trawl. The experimental trawl is a modification of the standard
Long Term Resource Monitoring Program (LTRMP) slingshot balloon trawl. The trawl
is 4.8 m wide x 4.5 m long with 18 mm mesh (16 feet x 15 feet with 3/4-inch mesh). We
attached a 4-mm (3/16-inch) delta style mesh to the outside of this net to more
effectively capture small fish, particularly Macrhybopsis chubs. A standard trawl
sample is 350 meters (1,148 feet) long.

The pallid sturgeon was collected over primarily a sand substrate; some gravel was
present. Bottom dunes to 31 cm high were recorded at the sample site. The water
averaged 2.7 m deep and the bottom water velocity averaged 0.55 m/s. Surface water
velocity averaged 1.07 m/s. The water temperature was 29.6øC.

The collection site is classified as main channel border-unstructured strata (no
revetment or wing dams) and was located on an inside bend. Typically, inside bends in
the Mississippi River near Cape Girardeau have large sand flats with a point bar at the
downstream end. Sand dunes occurring in these areas range from 15 cm to 1.2 m
high. We determined substrate types by dragging a metal pole on the bottom.
Substrate firmness could be estimated as the pole ascended and descended a dune.
In general, the substrate was soft to firm sand when ascending a dune and firm sand or
cobble/gravel in the trough below the dune. We do not know if the pallid sturgeon was
captured on or below a dune or in some interstitial space between dunes.

We captured 46 fish along with the pallid sturgeon at the collection site. Species
composition was 52% channel catfish (Ictalurus punctatus), 32% blue catfish (Ictalurus
furcatus), 9% unidentified sturgeon, 2% gizzard shad (Dorosoma cepedianum), and 2%
sicklefin chub (Macrhybopsis meeki). Three of the four unidentified sturgeon were 100
- 150 mm long (these were probably Y-O-Y); the other was 258 mm long (probably age-
1). All of the other species captured were Y-O-Y.

We sampled 105 sites with the experimental trawl in 1998. Nineteen samples
produced 32 unidentified sturgeon that were less than 258 mm long; 28 were less than
150 mm long. Twelve of the 19 samples (63%) occurred at inside bends and 20 of the
32 unidentified sturgeon were captured in inside bends (62%). This suggests that Y-O-
Y sturgeon may be using inside bends as rearing habitat from June through October.
More research is needed to determine sturgeon distribution throughout the seasons
and over its entire historical range.

The Y-O-Y pallid sturgeon we collected was killed during the trawl sample, probably the
result of trauma. The specimen has been preserved and is in icthyological collections
at the University of Alabama. Bobby Reed (Louisiana Department of Wildlife and
Fisheries), an active member of the Louisiana Pallid Sturgeon Recovery Team, made
the initial verification of the vouchered specimen. The specimen was also verified by
Dr. Richard Mayden (University of Alabama).

Mike Petersen and David Herzog, Missouri Department of Conservation, Fisheries
Research, Assessment, and Monitoring Section, Long Term Resource Monitoring
Program, Open River Field Station, 3815 East Jackson Boulevard, Jackson, MO
63755, Phone: 573-243-2659, E-mail: Michael_Petersen@usgs.gov or
David_Herzog@usgs.gov