Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

41.  SWIMMING, SKIMMING, AND HUNKERING DOWN: STATION-HOLDING BY ACIPENSERIFORM FISHES AND ENTRAINMENT RISK BY DREDGES.

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

Doug Clarke, US Army Engineer Research and Development Center, Waterways Experiment Station, EE-W, 3909 Halls Ferry Road, Vicksburg, MS 39180-6199; Phone 601-634-3770, FAX 601-634-2398; Douglas.G.Clarke@erdc.usace.army.mil

Hydraulic dredges used in some rivers for sand-and-gravel mining and for channel maintenance create flow fields of varying size and strength.  Juvenile paddlefish and sturgeons inhabiting these rivers are not powerful swimmers and are believed susceptible to entrainment when in these flow fields.  Evaluating risk of entrainment, however, requires information on station-holding endurance and behavior of fish.  Laboratory swimming trials provide such data and allow development of empirical swimming performance models.  Studies on young-of-year paddlefish, lake sturgeon, and two populations of pallid sturgeon indicate that burst (escape) speeds of acipenseriform fishes are low (40-90 cm/s). Substantial variation exists in swimming endurance and behavior among species, among different sizes within a species, and between populations of the same species.  Superimposing appropriate swimming performance models on dredge flow field models allows the risk of entrainment to be estimated for different operational protocols and identification of the dredging protocol presenting the lowest threat of entrainment.