Behavior of American Shad, Alabama Shad, and Blueback Herring in Response to a Simple Attraction Flow within a Navigation Lock

Navigation locks are often the only means of passage for anadromous fishes.  However, the static nature of these systems provides no environmental cues to attract migrants.  From 2000 through 2006, we implanted American shad and blueback herring in the Santee-Cooper River System, and Alabama shad in the Apalachicola River and monitored their behavior in relation to artificial flow through the Pineopolis Lock and Dam and Jim Woodruff Lock and Dam.  We installed a simple siphon tube that produced a flow of ~1 m³/s at Pineoplis Lock and Dam and a pump system at Jim Woodruff Lock and Dam that produced ~0.5 m³/s.  Approximately 100 fish of each species were monitored over 2 seasons at each location.  All species showed an affinity to the attraction flow and an aversion to the walls and floor of the lock.  Bleuback herring concentrated in the volume of water from 1 – 4 m from the discharge, while American shad and Alabama shad preferred the volume of water from 3 – 10 m downstream of the discharge.  All species exhibited no directed movement in the absence of discharge.  Of shad entering the lock, passage exceeded 50%.