Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

14.  A GUIDE TO THE GONADAL DEVELOPMENT OF THE SHOVELNOSE STURGEON

Robert E. Colombo*, Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6511; Phone 618-536-7761; Fax 618-453-6095; jgarvey@siu.edu

James E. Garvey, Fisheries and Illinois Aquaculture Center, Department of Zoology, Southern Illinois University, Carbondale, IL 62901-6511; Phone 618-536-7761; Fax 618-453-6095; jgarvey@siu.edu

The demand for domestically produced caviar has led to increased harvest of the shovelnose sturgeon.  To determine whether these populations can withstand increased harvest, detailed information regarding sexual demographics is needed.  We sexed 308 shovelnose sturgeon sampled in the Middle Mississippi River during September 2001 through December 2003 to develop a guide to reproductive development.  Using evisceration, histology and portable ultrasound, we identified three of the four stages developed for male lake sturgeon development in shovelnose sturgeon and all seven of the stages of female development.  A total of seven intersexual fish were sampled coinciding with a 2% intersexuality rate, which is similar to other studies conducted on this population.  Female fecundity was positively related to body weight.  However, no relationship between fork length and fecundity occurred.  The sex ratio of the shovelnose sturgeon in the MMR did not differ from one to one.  This guide will allow for the rapid inspection of the gonad for sex and stage of development for the shovelnose sturgeon.