The Color Dolphin

You see green. I see GOLD!

FSF Staff May 21, 2010

While offshore fishermen are extremely opinionated, there’s certainly one thing we can all agree on—the shear popularity of dolphin. Five or 55-pounds, everyone loves them. These fast growing, relatively short-lived carnivores are abundant in tropical and subtropical seas throughout the Atlantic, Indian, and Pacific Oceans. They are routinely taken in the Gulf of Mexico, throughout The Caribbean and as far away as the Mediterranean and Sea of Japan.

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Photo: www.jasonarnoldcollection.com

Dolphin live for one sole purpose—to reproduce, and they do so repeatedly. Recent research suggests that mature dolphin may spawn every two to three-days for the duration of the entire spawning season, perhaps even year-round. Females may produce 70,000 eggs per session. Multiply that by an average lifespan of two or three-years, and the number of offspring from each spawning female can range into the millions.

Dolphin, like many game fish, are blessed with a coloration scheme called countershading, which they use to their advantage when sneaking up on flying fish and eluding predation.

To fuel their hectic libido, dolphin maintain a healthy appetite. They are typically aggressive, always hungry, and always on the move. They strike a variety of natural and artificial offerings with ferocity, fight just as hard as any other game fish, and are agile enough to swim circles around marlin. To top it off, grilled, fried, broiled or baked, fresh dolphin is delectable no matter how it’s prepared. While every fish can at times catch a severe case of lockjaw, it really is hard to imagine an all around better game fish.

Astonishingly, for a popular pelagic predator that already has so much going for it, dolphin also claim the prize as the most colorful and easily recognizable “big game” target on the planet. Their dramatic neon patterns are recognized around the globe by avid and novice anglers alike. Tourists embarking on charters out of every tropical port can’t help but go wild when a mean, green killing machine invades the spread and takes to the air. Many of these vacationers rarely see the ocean let alone a jumping game fish, so you can’t blame them for getting so hyped up. With volumes already written about how to catch these magnificent fish, it’s dolphins’ spectacular color patterns that I wanted to further investigate.

Contrary to what you may be thinking, dolphin do not actually have green skin. They are more transparent than anything else. What’s actually under the skin is what performs the magic. Dolphin are covered in pigment-containing, light-reflecting cells known as chromatophores, which are generated in the neural crest during embryonic development. The chromatophores are under muscular control and as they expand and contract, mechanisms translocate pigment and reorient the reflective plates within the chromatophores, allowing the fish to change from blue to green to gold. The process is quite remarkable and is called physiological color change.

While we generally associate dolphin with the color green, a great deal of underwater footage reveals that in their natural environment, packs of hungry ‘phins often cruise and hunt in hues of iridescent blue. If it weren’t for their gold tails stealthily slicing through the water, they would be nearly impossible to discern against the cobalt backdrop. Perhaps when dolphin are on the move in the azure depths in search of rich feeding grounds they blend in with their surroundings as a means of avoiding detection—a masterful chameleon sneaking up on prey while simultaneously avoiding succumbing to the same fate.

Dolphin, like many game fish, are blessed with a coloration scheme called countershading, which they use to their advantage when sneaking up on flying fish and eluding predation. These open water hunters feature light colored undersides, usually white or pale yellow, with dark green or blue shoulders and topsides. Seen from below dolphin disappear in the sunlight-filled waters above. Seen from above they dissolve into the azure depths below—an ingenious defense mechanism.

Once unsuspecting prey is located, dolphin light up like a neon sign—their broad bodies dominated by vibrant greens and yellows sparkling with vertical bands and random spots of electric blue, gold and shimmering silver. And while they all appear extremely similar; no two dolphin are exactly alike.

Set the hook in a fooled ‘phin and instinctively the majestic fish leaps skyward, dancing across the surface in an attempt to rid itself of the foreign tether and ultimately elude capture. As they defy gravity the fish’s acrobatic abilities and vibrant coloration are awe-inspiring, certainly leaving me convinced that dolphin are one of Mother Nature’s greatest gifts to anglers.

Commonly encountered to 30-pounds, true trophies exceeding the coveted 50-pound mark are prized the world over and continue to rank as one of the greatest achievements in any offshore angler’s career, regardless of what type or class of tackle the monster fish was subdued on. Mature males or “bulls” are easily distinguished by their high, flat forehead and are typically larger than females or “cows.” Adults travel alone or in pairs. Adolescents and minors referred to as “peanuts” and “schoolies” travel in packs, which can range from a few fish to several dozen. The kids don’t spend too much time with mom and dad for one simple reason; they’re on the menu.

Sink a gaff into a beaten ‘phin and it’s lights out. Vibrant, neon greens and metallic gold quickly fade into pale yellows and dull blues as life inevitably turns to death. But why exactly do dolphin portray such distinct hues across the color spectrum, and what special purpose do these particular patterns serve? Understanding that even with the soundest science we’ll likely never know all of the answers, for now we can only speculate.

Does the color dolphin play a role in some form of communication system? It’s a known fact that sailfish work in unison to corral bait-balls. They communicate with one another by body posture and skin coloration, raising their sails while simultaneously illuminating vertical bands as they charge in for a kill. Unless I missed the greatest discovery of mankind, dolphin sure as heck aren’t communicating with one another like you and I do. Thus, it’s safe to assume that subtle hue alterations and pattern changes are, in fact, an indication of their next move to the remainder of the pack.

Colors in the aquatic kingdom also indicate hierarchy and dominance, like the most colorful fish eats first kind of thing. This leads us to believe that precise color patterns may also relate to mating purposes with unique shades or patterns indicating maturity and determining which male is the real stud of the pack.

While there are still many mysteries, what we do know for certain is that dolphin change color and alter their hues depending on mood changes and to confuse predators and prey. Aggression, excitement, fear and spawning all trigger pattern and color adaptations. Light of day also affects how they appear, as a decrease in sunlight means a decrease in reflective index.

It’s important to remember that while we see dolphin as green, the fish’s perspective is altogether different. Dolphin have developed eyes that only detect colors typical of their environment. Open ocean pelagic fish have limited color vision and detect only a few colors if any other than black and white. This is not surprising from a biological point of view, because offshore waters appear mainly blue and contain few other colors.

In closing, it doesn’t take a Ph.D. in Marine Biology to know that color plays an important role for fish. We’ve all watched Discovery’s Life. Countless aquatic species rely on camouflage to capture prey and escape the same fate, and dolphin are no exception. Some species use alluring coloration to attract mates, while others use false eyes to confuse predators. As far as we’re concerned, regardless if it’s for reproductive, hunting, survival purposes or a combination thereof, it’s clear the color dolphin serves numerous purposes. This game fish’s spectacular canvas is clearly a work of evolutionary art and maybe, just maybe, the color dolphin is nature’s way of rewarding us and reminding anglers in every ocean to be responsible stewards of the sea and to appreciate every fish we catch.

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