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Shad Cam: Through the Viewing Window

Shad Cam is focused on the viewing window at the exit channel of the fishway. If you’re seeing a fish on Shad Cam, that means that it successfully swam through the fishway and is about to re-enter the James River just upstream of the dam.

Interpreting what you see…

  • Water flows from the right (upstream of the dam) to the left, past the window and through the remaining section of the fishway.
  • The viewing window is four feet wide, seven feet tall, and has five inch thick glass so that it is durable enough to stand up to the underwater conditions.
  • The white background board is used to estimate the size of fish as they pass by the window. Each of the vertical black lines on the board are spaced six inches apart so that we can accurately estimate a fish’s size.
  • A fish’s position between the background board and the viewing window can affect the size estimation to a small degree through forced perspective.
  • Behind the black panel on the left hand side are lights which allow for nighttime viewing. These lights don’t affect fish behavior but they do allow us to see nocturnal fish species that prefer to migrate at night, like Sea Lamprey.