Q: This was the largest of several lookdowns we recently caught while casting around some rocky islands. My question has to do with its shape being nearly two-dimensional, as this photo - taken by my friend Dwayne - shows. Not very many fish (at least those that swim upright, unlike flounder) have this shape. Why have lookdowns evolved this way? What's the advantage?
Cecil Roy Glomstrobber
El Paso, Texas
A: Lookdowns are truly the epitome of the flat shape. But they're just the last step in the evolution of this design among the jacks. They have a close relative, the moonfish, which approaches the lookdown in these extreme dimensions. Many other jacks, like the permits and pompanos, are also relatively flat. One can only speculate as to how this design benefits the species. The prevailing wisdom is that flatness enhances quick turning and maneuverability, but lookdowns are also endowed with flashy pigments, and they are almost always in tight, very acrobatic schools. Somehow all this must play to their advantage in being a very successful species despite their oddly beautiful appearance.
- Bob Shipp