Magic of the Mahi-Mahi
by Steve Hicks
Spectacular color patterns are a given on many saltwater gamefish, but most pale in comparison to the rainbow effect of a hooked dolphin as it leaps and spins, spraying a shower of iridescent green, gold, blue, silver, and yellow. Beautiful as they are when "lit up" during the fight, the rainbow effect quickly fades after you land the fish-and it disappears altogether once the fish is dead. How do dolphin make this neon-like display, and why does it end so abruptly?
Some fish, like grouper and flounder, change colors because pigments in their skin are triggered when the fish are stressed, excited, or in need of some quick camouflage. But this phenomenon does not apply to dolphin, which have a dull silver skin pigment. The dolphin owes its multi color splendor to its three-dimensional scales, which reflect light yet are not themselves pigmented. The scales react to signals from the fish's nervous system, actually moving in response to the dolphin's surroundings and level of excitement. These tiny movements allow the scales to catch and reflect light at different angles like a prism. During the mating season, for example, the scales "light up" to attract the opposite sex. When excited by a pack of baitfish or scared by a large predator (or a hook in the jaw), dolphin become agiated-and those scales move. Once the dolphin is removed from the water, its nervous system overloads, the scales stop moving, and the colors fade to a silver-gray.
How can understanding this effect help you catch more fish? When you see a dolphin in your chum line or eyeballing bait, pay attention to its colors. If they,lre dull, the fish probably isn't turned on by your enticements. Try casting something different or ripping one along the surface.
On the other hand, if the fish is already lit up when you see it - hang on!