An indirect benefit of my research for salmon-fishing information was what I learned from Dr. Stephen Easter, a professor in the Zoology Department of the University of Michigan. Most important was that his laboratory fish favoured red. Common sense suggested this would likely also hold true with wild gamefish. A red lure would be the first to consider. If, however, red rays were filtered out at the planned fishing depth or at a certain time of the day, it would be necessary to identify the next best colour.
Visibility varies with water depth, light intensity, and, of course, water clarity.
Colours below their visibility range show as grey or black. Naturally, clear water and ample light are musts for fish to see true colours. Although the Great Lakes and larger inland lakes qualify as clear, this is not so for many inland waters. Limnologists have found smaller and usually more fertile lakes vary in turbidity. On lakes stained brown or obviously cloudy, anglers should not rely on this colour-selection idea.