Nearly 200 fish were released below Lock and Dam 2 (LD2) in the Upper Mississippi River and tracked to determine both whether and how they passed through this structure, and if passage could be explained using a computational fish passage model (FPM) which combines hydraulics with fish swimming performance. Fish were either captured and released downstream of LD2 in Pool 3 or captured in Pool 2 (upstream of LD2) and displaced below LD2. Tagged fish were tracked using 13 archival receivers located across LD2. Approximately 90% of all fish approached LD2 many times with the displaced species likely attempting to home. Of 112 common carp, 26% passed through LD2 with 15% (most) going through the lock and 6% through the spillway gates. Similar values were seen for bigmouth buffalo. In contrast, although 42% of 31 channel catfish passed through the lock, only 3% went through the gates. Finally, of 22 walleye, only 14% passed through the lock and none through the gates. Ninety percent of all documented passages through the spillway gates occurred when the gates were out of the water and water velocities through these gates were at their lowest levels, an attribute described and predicted by the FPM at LD2. This study strongly suggests that fish passage through spillway gates of LDs is determined by water velocity and can be predicted with a FPM, whereas passage through locks is determined by species-specific behavioural preferences. Both attributes could be exploited to reduce passage of invasive carp at certain locations.
Bibliographical noteFunding Information:
We thank the Minnesota Department of Natural Resources (MN DNR) and U.S. Fish and Wildlife (USFWS) for funding this work through a Minnesota Outdoor Heritage Fund allocation and an USFWS grant. We are grateful to Reid Swanson, Justine Dauphinais, and Daniel Krause for their advice and assistance in the field. We also thank Connor Erickson, Gavin Aguilar, Lucas Lagoon, Dalton McGowan, and Rosemary Daniels for their help sampling and tracking fish. The U.S. Army Corps Engineers and MN DNR provided much helpful advice and data. Finally, we acknowledge help from both the Minnesota Supercomputing Institute and the Institute for Cyber‐Enabled Research.
- fish passage model
- lock chamber
- open river
- spillway gates
- swimming performance