Animalia Life

Coryphaena hippurus
FAMILY
Coryphaenidae
TAXONOMY
Coryphaena hippurus Linnaeus, 1758, type locality not specified.
OTHER COMMON NAMES
English: Dolphin, dorado, mahi-mahi; Spanish: Dorado; Hawaiian: Mahi-mahi; Japanese: shiira.
PHYSICAL CHARACTERISTICS
Elongate and fusiform body. A long dorsal fin, with 58–66 soft rays, arises above the eye and extends to the caudal peduncle. The anal fin is concave, has 25–31 soft rays, and extends from the anus to the caudal peduncle. The pectoral fin is more than half the length of the head, and the caudal fin is forked. Adult males have a pronounced bony crest on the front of the head. Brilliantly colored, with metallic greens and blues on the back and flanks, gold on the flanks, and yellow and white shades on the venter. Juveniles and young adults have vertical bars on the flanks. Grows to longer than 83 in (210 cm) but lives for only about 5 years.
DISTRIBUTION
Tropical, subtropical, and warm temperate waters worldwide.
HABITAT
Inhabits pelagic surface waters but ventures inshore to forage. Reported to enter brackish waters, such as estuaries.
BEHAVIOR
Forms highly migratory schools, aggregations, or groups. Attracted to boats, ships, and floating objects, such as palm fronds or tree trunks. Also attracted to fish aggregation devices.
FEEDING ECOLOGY AND DIET
A predator upon smaller fishes and squids but also takes pelagic crustaceans and even macroplankton.
REPRODUCTIVE BIOLOGY
This species matures sexually in the wild at only 4–5 months. Females mature at about 13.5 in (34.3 cm) and males at 16.5 in (42 cm) fork length (the distance between the snout and the midpoint in the “fork” of the caudal fin). Eggs are pelagic, buoyant, spherical, about 0.05 in (1.4 mm) in diameter, and clear in color; the oil globule is yellow. Eggs hatch after 1.5 days and larvae measure just under 0.16 in (4 mm) at hatching. Melanophores develop on the head, trunk, and tail soon afterwards. Larvae begin to feed upon planktonic copepods after the yolk sac is absorbed, and growth is rapid.
CONSERVATION STATUS
Not listed by the IUCN, but may be vulnerable to overfishing. Recognized under Annex I of the 1982 Convention on the Law of the Sea because of its migratory habits.
SIGNIFICANCE TO HUMANS
A highly prized commercial and game fish that also is taken in subsistence fisheries. Reported to be ciguatoxic in some areas. Ciguatera poisoning is caused by the cumulative deposition of a class of polyether toxins within the tissues of fishes. The toxins are produced by certain microscopic dinoflagellate organisms of the genus Gambierdiscus, and are transmitted by the mechanism of the food chain, increasing in intensity by a factor Coryphaena hippurus Nematistius pectoralis of ten in each successive level within the chain. The common dolphinfish acquires these toxins from prey fishes, which in turn acquire them from smaller fishes or zooplankton that have ingested dinoflagellate during feeding. If this fish is consumed by man, the concentrated poison contained within its tissues causes neurological damage that may be fatal.

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