Lakes in gravel pits are usually relatively unproductive but Ruth's Lake near Marshalltown was found to have a larger fish population than has been reported for any other water, except for carp ponds where the fish are artificially fed. When this lake was treated with rotenone, over 1200 pounds of fish per acre, were collected, compared to the 100 to 400 pounds per acre found in most lakes and ponds (Carlander, 1950).
Proceedings of the Iowa Academy of Science
©1951 Iowa Academy of Science, Inc.
Carlander, Kenneth D.
"An Unusually Large Population of Fish in a Gravel Pit Lake,"
Proceedings of the Iowa Academy of Science, 58(1), 435-440.
Available at: https://scholarworks.uni.edu/pias/vol58/iss1/55