Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

15.  ASSESSMENT OF SCAPHIRHYNCHUS SPP. SPAWNING AND REARING LOCATIONS IN THE MIDDLE MISSISSIPPI RIVER: INSIGHTS FROM COLLECTION OF LARVAL AND YOUNG-OF-THE-YEAR FISHES.

David P. Herzog*, Missouri Dept. of Conservation, Open Rivers and Wetlands Field Station, Jackson, MO 63755;  Phone 573-243-2659; FAX 573-243-2897; David.Herzog@mdc.mo.gov

Robert Hrabik, Missouri Dept. of Conservation, Open Rivers and Wetlands Field Station, Jackson, MO 63755; Phone 573-243-2659; FAX 573-243-2897; Robert.Hrabik@mdc.mo.gov

Ron Brooks, SIUC Fisheries and IL Aquaculture Center, Life Sciences 2 Room 173, Carbondale, IL, 92901-6511; Phone 618-453-6072; FAX 618-453-6095; rbrooks@siu.edu

Timothy W. Spier, WIU Department of Biology, 1 University Circle, Macomb, IL, 61455; Phone 309-298-1266; FAX 309-298-2270; tw-spier@wiu.edu

David Ostendorf, Missouri Dept. of Conservation, Open Rivers and Wetlands Field Station, Jackson, MO 63755; Phone 573-243-2659; FAX 573-243-2897; David.Ostendorf@mdc.mo.gov

Joe Ridings, Missouri Dept. of Conservation, Open Rivers and Wetlands Field Station, Jackson, MO 63755; Phone 573-243-2659; FAX 573-243-2897; Joseph.Ridings@mdc.mo.gov

Jason Crites, Missouri Dept. of Conservation, Open Rivers and Wetlands Field Station, Jackson, MO 63755; Phone 573-243-2659; FAX 573-243-2897; Jason.Crites@mdc.mo.gov

Collin Beachum, Missouri Dept. of Conservation, Open Rivers and Wetlands Field Station, Jackson, MO 63755; Phone 573-243-2659; FAX 573-243-2897; Collin.Beachum@mdc.mo.gov

Rob Colombo, SIUC Fisheries and IL Aquaculture Center, Life Sciences 2 Room 173, Carbondale, IL, 92901-6511; Phone 618-536-7761; FAX 618-453-6095; rcolombo@siu.edu

In 1998 the Open Rivers and Wetlands field station developed a small mesh benthic trawl (e.g., Missouri trawl) to sample small-bodied fishes in large river systems.  Young-of-the-year pallid sturgeon (Scaphirhynchus albus) were detected for the first time in the Middle Misssissippi River (MMR) using this technique.  After these captures, we sampled the MMR from 1998 through 2004 to document spawning timing, location, and duration of Scaphirhynchus spp using two sizes of Missouri trawls, plankton nets, and egg trays.  We were unable to document egg deposition using egg tray samplers and captured no larval Scaphirhynchus spp. using plankton nets.  However, eggs of several fish species and larval Scaphirhynchus spp. were captured in the Missouri trawls.  Our findings indicate that successful reproduction of shovelnose sturgeon (Scaphirhynchus platorynchus) and pallid sturgeon (S. albus) is occurring in the MMR.  However, because we capture few age 1 Scaphirhynchus spp, we suggest that successful recruitment to age 1 may be a limiting factor for long-term viability in the MMR.