Migratory Characteristics and Passage Efficiency of Fishes at Two Dams on the Alabama River, Alabama

Abstract

Fish passage facilities are a widely accepted mitigation tool at many dams in the United States to assist migratory fish species to upstream spawning areas on the U.S. Atlantic and Pacific coasts. Here we investigated the potential to move fish through two locks on the Alabama River-- Millers Ferry Lock and Dam and Claiborne Lock and Dam-- using specialized lock operations. We used manual tracking combined with submersible ultrasonic receivers (SUR) deployed both above and below each dam, as well as inside the navigational lock chamber to determine whether fish passage occurred. We recorded over 359,000 detections of 157 individuals with the SURs and 144 manual detections of 67 individuals. Most fish movement past dams occurred during the spring, when many riverine fish make spawning migrations. Our results suggest that specialized lock operations along the Alabama River increase opportunities for upstream fish passage although relatively few fish moved through the lock chambers.