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-- D o l p h i n s --
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| Q 1. | ||
| How does the dolphin fish change color? |
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| Q 2. | ||
| Is a dolphin a fish or a mammal? |
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| Q 3. | ||
| Have dolphin fish ever been kept in captivity? |
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| Q 4. | ||
| Are baby dolphin fish frequently found? |
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| Q 5. | ||
| Is a dolphin a fish or a mammal? |
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| Q 6. | ||
| I have eaten dolphin roe and I understand that a dolphin is a mammal. How is this possible? |
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| Q 7. | ||
| I recently heard some talk about the pompano dolphin. Is this a type of pompano or is it a dolphin? |
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| Q 8. | ||
| Recently one member of a charter boat party fishing off Stuart hooked a female dolphin and was bringing it up to the boat when a shark began chasing the fish. All at once a big dolphin appeared, instantly changed color from the usual green-gold to blue and attacked the shark, butting it repeatedly. The male failed to drive off the shark, which grabbed the female dolphin and sank. The bull dolphin made a circle, took one of the baits and was boated. It weighed thirty pounds and was still blue when brought in to the dock. Was this incident unusual? |
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| Q 9. | ||
| Please tell me if the enclosed newspaper strip drawing called the “Sea Bream” is what we call the dolphin. It looks like the fish that we all call dolphin, but the artist has named it “Sea Bream.” |
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| Q 10. | ||
| What about the worms I find in dolphin fish caught off Miami? I found so many worms in 28-pound bull dolphin that I had to dispose of the entire fish. In others, both large and small, I found perhaps six or seven worms that I was able to cut away. I know of the worms often found in groupers but these are different. We caught dolphin outside Marathon, in the Florida Keys, and found no worms. I wonder if this was unusual, or did I just happen to catch worm-free fishes? |
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| Q 11. | ||
| Is there some “rule of thumb” formula that would enable sportsmen to distinguish between the pompano dolphin and the common dolphin. Unlike professional marine biologists, the average sport fisherman is either unwilling or unqualified to count gill rakers, or make other detailed checks. Isn't there some simple method of determining which is which? |
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| Q 12. | ||
| The dolphin-fish has brilliant iridescent colors while being caught on hook and line, but turns a dull gray at death. Is the iridescence caused by fright during the struggle on the line, or is it maintained during normal undisturbed periods? |
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| Q 13. | ||
| The interesting subject article, “Dolphin Spectacular,” in Sea Frontiers, Vol. 17, No. 4, states that... “It has been demonstrated that dolphin can be successfully reared...” and “The possibilities that this great fish offers for aquaculture are equally exciting.” Can you suggest a source of information dealing with the facilities and procedures best suited to the successful raising of dolphin in captivity? |
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| Q 14. | ||
| In the enclosed bottle is a small fish (preserved in alcohol) that I caught at Jupiter Inlet, Florida. When alive, it was either black or dark brown on the lower half of its body from the lateral line down, with the upper half pink or rose colored. Its vertical stripes are still visible. The fish was swimming on the surface when caught and did so in the aquarium for a few days. Was this natural behavior? |
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| Q 15. | ||
| How did the dolphin-fish (Coryphaena spp.) happen to be called dolphin when mammals of the same name also existed? |
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| Q 16. | ||
| Which marine animal was named dolphin first the mammal or the pelagic fish? |
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| Q&A 1. | How does the dolphin fish change color? |
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| Anyone who has fished for dolphin (Coryphaena hippurus) will recall the remarkable play of colors which takes place in the fish’s skin as it dies. This change in color is accomplished by the myriad chromatophores (color cells) in the skin of the fish. Chromatophores containing blue, green, yellow, brown, and other pigments are capable of alternately expanding and contracting, being so closely crowded together that as certain ones contract and others expand, the effect will be a sudden or gradual change in the hue of the fish. Dolphins are normally a brilliant blue-green or bright green above with bronze-tinted yellow sides covered with a peppering of blue dots when alive, but after death all the chromatophores tend to contract, leaving the fish a pale grayish-brown in color. |
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| Q&A 2. | Is a dolphin a fish or a mammal? |
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| The name “dolphin” is correctly applied to two different sea creatures, one a fish, and the other a mammal. “Dolphin” by itself usually refers to any of the various species of long-nosed, smooth-toothed porpoises, which are mammals related to the whale. The common “porpoise” of Florida waters is actually the bottlenosed dolphin, Tursiops truncatus. The other “dolphin” which is more correctly called the dolphin fish or dorado (Coryphaena hippurus), is a large oceanic fish known for its spectacular color changes when hooked. |
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| Q&A 3. | Have dolphin fish ever been kept in captivity? |
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| Because of their size and great activity, dolphin fish, Coryphaena hippurus, unless very small, usually do not survive for long if confined in a tank or small live car. However, in large pens maintained by the University of Hawaii, as well as in the oceanarium at Marineland, Florida, dolphin fish have survived for several months at a time. In captivity they appear to spend almost their entire time at the surface of the water, swimming rapidly with a constant sculling motion of the tail. They showed a number of their characteristic color changes, particularly when excited at feeding time. |
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| Q&A 4. | Are baby dolphin fish frequently found? |
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| A dolphin fish, (Coryphaena hippurus), measuring a half inch in length was captured in front of the Marine Laboratory building at Virginia Key on December 4th, and is now thriving in a small tank of sea water. The dolphin fish is one of the best known of tropical game fishes, and is also excellent eating. The colors are iridescent blue, green, yellow, and coppery, but these splendid hues fade rapidly to a dull brownish gray after death. |
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| Q&A 5. | Is a dolphin a fish or a mammal? Miami, Florida |
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| Both. A member of the porpoise family is called dolphin, while one of the most beautiful and interesting of Florida's fishes goes by this name. The dolphin (Coryphaena hippurus) can change its color with remarkable swiftness, and beautiful hues of lavender, green, purple, and yellow chase each other across the fish while it is active, particularly immediately after it is landed. Dolphin appear to travel in pairs at times and frequently when one fish is hooked its mate will swim around the boat, apparently grieving, and can often also be caught. In addition to providing exciting sport, the dolphin is an excellent food fish. |
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| Q&A 6. | I have eaten dolphin roe and I understand that a dolphin is a mammal. How is this possible? Miami, Florida |
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| “Roe” and “milt” are found only in fish. These are the names given to the ripe ovaries and testes of female and male fish, respectively. The source of confusion comes from the fact that two animals, one a fish the other a mammal, are both called “dolphin”. The reader apparently ate the roe of the dolphin fish (Coryphaena hippurus) which also is known as dorado. This dolphin is said to be the most beautiful of all game fish and is considered one of the fastest. It is iridescent bluish gold and blue-black toward the tail. The mammal which is called a dolphin is commonly known as a porpoise, and is known scientifically as Delphinus delphis. In some English-speaking countries, however, porpoises are referred to as dolphins. Porpoises, of course, do not have roe. |
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| Q&A 7. | I recently heard some talk about the pompano dolphin. Is this a type of pompano or is it a dolphin? Ft. Lauderdale, Florida |
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| A second species of dolphin (family Coryphaenidae) occurs in Florida waters along with the common dolphin, Coryphaena hippurus. The second species, Coryphaena equisetus, is often called pompano dolphin because its lateral profile is somewhat broader than the common dolphin. The pompano dolphin is sometimes called the little dolphin and is a true dolphin. The dolphin is one of the species of fish being studied at the Marine Laboratory of the University of Miami. In order to determine the relative numbers of the two species in the catches, the Marine Laboratory would be grateful for information on the capture of the pompano dolphin. |
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| Q&A 8. | Recently one member of a charter boat party fishing off Stuart hooked a female dolphin and was bringing it up to the boat when a shark began chasing the fish. All at once a big dolphin appeared, instantly changed color from the usual green-gold to blue and attacked the shark, butting it repeatedly. The male failed to drive off the shark, which grabbed the female dolphin and sank. The bull dolphin made a circle, took one of the baits and was boated. It weighed thirty pounds and was still blue when brought in to the dock. Was this incident unusual? Stuart, Florida |
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| Dr. C. Richard Robins of the University of Miami Institute of Marine Science reports that on numerous occasions he has observed pairs of dolphins and various species of jack around fishing boats. Frequently when one member of the pair is hooked the second fish will follow it to the surface. On one occasion, Dr. Robins recalls, a jack struck the line, possibly by accident. With these observations in mind the dolphin behavior that you described seems quite reasonable. |
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| Q&A 9. | Please tell me if the enclosed newspaper strip drawing called the “Sea Bream” is what we call the dolphin. It looks like the fish that we all call dolphin, but the artist has named it “Sea Bream.” Chevy Chase, Maryland |
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| From your description and the enclosed drawing it seems apparent that the fish is, indeed, the dolphin Coryphaena hippurus. The dolphin has a world-wide range in warm seas and undoubtedly has had many names given to it through the years. It is known as the “dorado” in many Spanish-speaking areas, and as the “mahi mahi” in Hawaii. We have not seen it referred to as the “sea bream”, but apparently it is a local name, or possibly an editing error. |
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| Q&A 10. | What about the worms I find in dolphin fish caught off Miami? I found so many worms in 28-pound bull dolphin that I had to dispose of the entire fish. In others, both large and small, I found perhaps six or seven worms that I was able to cut away. I know of the worms often found in groupers but these are different. We caught dolphin outside Marathon, in the Florida Keys, and found no worms. I wonder if this was unusual, or did I just happen to catch worm-free fishes? Miami, Florida |
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| There is considerable variation in the numbers of parasites in a species of fish in different areas, at different seasons and in different years. Virtually all fishes are hosts for some parasites, however. Infected dolphin can be safely eaten, but it is advisable to cook the fish well. For an article on this subject, see Sea Frontiers, Vol. 10, No.5, Christmas, 1964. |
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| Q&A 11. | Is there some “rule of thumb” formula that would enable sportsmen to distinguish between the pompano dolphin and the common dolphin. Unlike professional marine biologists, the average sport fisherman is either unwilling or unqualified to count gill rakers, or make other detailed checks. Isn't there some simple method of determining which is which? New Orleans, Louisiana |
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| There is no “rule of thumb” formula for distinguishing these fishes, but the following characteristics may help. Pompano dolphin have a greater body depth than common dolphin; the body depth at its greatest is more than one fourth the distance between the tip of the snout and the fork of the tail. This depth occurs near the middle of the body instead of just behind the head as in the common dolphin. The tail fin of the pompano dolphin is much more forked, the pectoral fin is much smaller, only barely extending past the pelvic fin rays, and the dorsal fin is proportionately much higher. The pompano dolphin has less than 56 dorsal fin rays and the common dolphin has more than 56. When alive, the pompano dolphin is more silvery and swims with a more snakelike motion. |
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| Q&A 12. | The dolphin-fish has brilliant iridescent colors while being caught on hook and line, but turns a dull gray at death. Is the iridescence caused by fright during the struggle on the line, or is it maintained during normal undisturbed periods? Northeast Harbor, Maine |
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| The blue, yellow and green colors of the dolphin, gleaming with iridescent tinges, are the natural colors of the fish and are apparently maintained during normal undisturbed activity. As you know, the colors begin to fade almost immediately when the fish dies. The common dolphin, Coryphaena hippurus, and the pompano dolphin, C. equiselis, are the subjects of an interesting article in the July-August, 1971, issue of Sea Frontiers. |
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| Q&A 13. | The interesting subject article, “Dolphin Spectacular,” in Sea Frontiers, Vol. 17, No. 4, states that... “It has been demonstrated that dolphin can be successfully reared...” and “The possibilities that this great fish offers for aquaculture are equally exciting.” Can you suggest a source of information dealing with the facilities and procedures best suited to the successful raising of dolphin in captivity? Lantana, Florida |
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| In the article “Dolphin Spectacular,” the author was speculating on the possibility of rearing dolphins. These fish have been successfully reared from subadult to adult in several commercial marine aquaria, including the Miami Seaquarium and Marineland. Rearing dolphins commercially for food, however, poses different sorts of problems. They must be raised in quantity and command a high price in the marketplace in order to turn a profit. At present, the market for dolphin is extremely limited. Techniques for inducing females to spawn and subsequent hatching of the eggs under artificial conditions must be developed. One of the most critical stages in rearing any marine animal is the period when the larvae switch from yolk nourishment to active feeding. Abundant food of the proper type must be readily available. Water quality must be carefully controlled and maximum capacity of the rearing ponds or tanks determined. The dolphin is a voracious eater and abundant food, cheaply obtained, must be available. These are a few of the numerous problems that have to be worked out for every animal that is to be raised on a commercial basis, and to the best of our knowledge, none of these has been studied for this fish. However, some experimentation on rearing techniques for dolphin has now begun at the University of North Carolina in its Sea Grant Program. |
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| Q&A 14. | In the enclosed bottle is a small fish (preserved in alcohol) that I caught at Jupiter Inlet, Florida. When alive, it was either black or dark brown on the lower half of its body from the lateral line down, with the upper half pink or rose colored. Its vertical stripes are still visible. The fish was swimming on the surface when caught and did so in the aquarium for a few days. Was this natural behavior? North Palm Beach, Florida |
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| The fish is a young of Coryphaena hippurus, the dolphin, which can be distinguished from the closely related C. equisetis, the pompano dolphin, in a number of ways. The dolphin has a pattern of alternating dark and light bars, and a dark pelvic fin, while that of the pompano dolphin is clear. It also has a dark caudal fin except for the tips of each lobe, whereas in the pompano dolphin the posterior half of the caudal fin is usually unpigmented. Young Coryphaena sp. are often collected at the surface at night using a night-light, and sometimes they are collected in the daytime at the surface with a plankton net. It does not appear unusual, therefore, for young dolphin to be swimming at the surface. Good references on this subject are “On the Identification, Distribution, and Biology of the Dolphins, Coryphaena hippurus and C. equisetis” by R.H. Gibbs, Jr. and B.B. Collette in Bulletin of Marine Science of the Gulf and Caribbean, 9(2): 117-152, and “Dolphin Spectacular,” Sea Frontiers, Vol. 17, No. 4, July-August, 1971. |
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| Q&A 15. | How did the dolphin-fish (Coryphaena spp.) happen to be called dolphin when mammals of the same name also existed? Miami, Florida |
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| The misapplication of the name dolphin to both the fish and mammal exists only among English-speaking peoples, and the reason for this can only be inferred. Perhaps early English explorers in unfamiliar tropical seas were confused by the behavioral similarities of these animals (both tend to school, leap out of the water, and swim at the surface with their head breaking the water's surface). On the other hand, these explorers often gave common names to plants and animals for no better reason than that it reminded them of something with which they were familiar. They were desperately trying to create some order out of their encounters with entirely new faunas and floras, and did not realize the confusion that might arise at a later date. |
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| Q&A 16. | Which marine animal was named dolphin first the mammal or the pelagic fish? Birmingham, Michigan |
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| In the ancient sense of the word, a dolphin is a marine mammal. From bas-reliefs and sculptures, it is clear that, to the Greeks, delphinus was the marine mammal now known as dolphin. The English word dolphin, derived from Greek and Latin, was in use as “dolfin” for the marine mammal as early as the thirteenth century. The use of the term dolphin for the fish Coryphaena hippurus is much more recent. It may have resulted from an error on the part of early English explorers who confused dorado, the Spanish name for the fish, with dolphin. According to The Oxford English Dictionary, the first recorded use of the word dolphin for the fish may have been in 1627 when Captain John Smith reported using hooks to catch dolphins, or dorados. The naming error spread, and the beautiful fish was referred to in English poems by Lord Byron and Elizabeth Barrett Browning as a dolphin, rather than as a dorado. |
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Rosenstiel School of Marine & Atmospheric Science Library
University of Miami, FL USA 4600 Rickenbacker Causeway, Miami, Florida 33149 Phone: 305 421 4060 Fax: 305 421 9306 E-mail: libcirc@rsmas.miami.edu |
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