Posts: 8772
| sworrall - 1/29/2010 10:49 AM
The transition from cone to rod vision begins before the sun sets. By dark, the fish's eye is adjusted to 100% rod vision, and no color is available. The transition back to cone vision begins around dawn and is at 100% color receptor around sunrise or so. This process happens on a biological clock for the fish, and doesn't change as the days shorten in the fall through winter, which is interesting.
That certainly IS interesting. If there's a period of time after sunset in the fall where they are still relying on their cone receptors, does that also mean that they probably have a very difficult time finding prey during that time unless they can rely on the lateral line? And in the morning, since it gets light later, they've already made the transition from rod vision back to cone vision, but with no available light to help them see color...
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