Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

49.  TYPES AND OCCURRENCE OF PHYSICAL ANOMALIES IN SCAPHIRHYNCHUS SPECIMENS OF THE LOWER AND MIDDLE MISSISSIPPI RIVER.

Bradley R. Lewis*, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, EE-A, Vicksburg, MS 39180-6199; Phone 601-634-3481; Fax 601-634-3560; Bradley.R.Lewis@erdc.usace.army.mil

Catherine E. Murphy, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, EE-A, Vicksburg, MS 39180-6199; Phone 601-634-4233; Fax 601-634-3560; Catherine.E.Murphy@erdc.usace.army.mil

Steven G. George, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, EE-A, Vicksburg, MS 39180-6199; Phone 601-634-2897; Fax 601-634-3560; Steven.G.George@erdc.usace.army.mil

Jan Jeffrey Hoover, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, EE-A, Vicksburg, MS 39180-6199; Phone 601-634-3996; Fax 601-634-3560; Jan.J.Hoover@erdc.usace.army.mil

K. Jack Killgore, U.S. Army Engineer Research and Development Center, 3909 Halls Ferry Road, EE-A, Vicksburg, MS 39180-6199; Phone 601-634-3397; Fax 601-634-2398; Jack.Killgore@erdc.usace.army.mil

Sturgeon belong to an ancient and robust group of fishes whose form has withstood the tests of evolutionary time and environmental pressure.  Specimens encountered in the wild that exhibit visible signs of gross physical trauma often look to the naked eye to be in otherwise good condition.  Frequency and type of visible physical anomalies were observed in 153 pallid (Scaphirhynchus albus) and 4301 shovelnose (S. platorynchus) sturgeon specimens captured in the middle (St. Louis, MO to Cairo, IL) and lower (below Cairo, IL) Mississippi River from 1997-2004.  Frequency of anomaly for all specimens was approximately 5%.  Frequencies among the types of anomalies differed between the lower and middle river sections.  In the lower river, injuries from foreign objects (typically rubber bands) comprised over 25% of the anomalies observed and may have contributed to other types of anterior injury including notched rostra, reduced eyes, deformed barbels and misshapen pectoral fins.  This combined group would comprise over 80% of the lower river anomalies.   In the middle river, over half of the observed anomalies involved damage to the caudal peduncle, usually a missing tail.  Simple length-weight relationships were compared for anomalous and non-anomalous specimens and demonstrated no obvious disparity.