The common dolphin is the larger of the two very similar species in the family Coryphaenidae, both of which are cosmopolitan in warm seas. This fish is one of the top offshore gamefish among anglers and is an excellent, hard-fighting species that puts on an acrobatic show once hooked.
dolphinfish, common dolphinfish, mahimahi, mahi mahi, dorado; Chinese: fei niau fu, ngau tau yue; French: coryphéne commune; Italian: lampuga; Japanese: shiira, toohyaku; Portuguese: doirado, dourado; Spanish: dorado, dorado com ún, lampuga.
Identification Of Common Dolphin
The body is slender and streamlined, tapering sharply from head to tail. Large males, called bulls, have high, vertical foreheads, while the female’s forehead is rounded. The anal fin has 25 to 31 soft rays and is long, stretching over half of the length of the body. The dorsal fin has 55 to 66 soft rays. Its caudal fin is deeply forked; there are no spines in any of the fins; and the mouth has bands of fine teeth.
Coloring is variable and defies an accurate, simple description. Generally, when the fish is alive in the water, the common dolphin is rich iridescent blue or blue-green dorsally; gold, bluish-gold, or silvery gold on the lower flanks; and silvery white or yellow on the belly. The sides are sprinkled with a mixture of dark and light spots, ranging from black or blue to golden. The dorsal fin is rich blue, and the anal fin is golden or silvery. The other fins are generally golden yellow, edged with blue. Dark vertical bands sometimes appear when the fish is attacking prey. The color description of the dolphin is difficult because it undergoes sudden changes in color, which occur in an instant, often when the fish is excited. When the fish is removed from the water, however, the colors fluctuate between blue, green, and yellow; the brilliant colors that were apparent when in the water fade quickly. After death, the fish usually turns a uniform yellow or silvery gray.
Size/Age Of Common Dolphin
The average size is 5 to 15 pounds, although larger catches up to 50 pounds are not uncommon. The alltackle world record is an 87-pounder caught in Costa Rica in 1976, and it has been rumored that fish up to 100 pounds have been caught by commercial longliners. The maximum length is reportedly 82 inches. Dolphin are fast growing and short lived. Few common dolphin live longer than 4 years, and most live just 3 years. Males grow larger than females and are capable of growing to 60 pounds in just 2 years, although this is exceptional and the result of consistently favorable warm water temperatures and abundant food.
The common dolphin is a prolific spawner and grows rapidly, meaning that it must by nature be an eating machine. Spawning season begins primarily in the spring or early summer and lasts several months in warmer waters. Dolphin reach sexual maturity in their first year of life and produce a large volume of eggs. Dolphin are schooling fish and are often congregated in large numbers, sometimes by the thousands. They are almost always between the surface and 100-foot depths, but they are encountered by anglers on or just under the surface and are probably the most surface-oriented of all big-game fish. This, plus the fact that they are visually oriented feeders that primarily forage in daylight, helps endear them to anglers. Offshore anglers frequently encounter packs of dolphin and are able to elicit strikes from several fish in quick order. These fish are evidently also migratory. It is believed that dolphin in both hemispheres migrate away from the equator in the spring and the summer and toward the equator in the fall and the winter.
Common dolphin are extremely fast swimmers and feed in pairs, small packs, and schools, extensively consuming whatever forage fishes are most abundant. Flyingfish and squid are prominent food in areas where these exist, and small fish and crustaceans that are around floating sargassum weed are commonly part of the diet, especially for smaller dolphin. Dolphin are very aggressive feeders, and they can move extremely fast to capture a meal.
The common dolphin is found worldwide in tropical and subtropical waters. In the western Atlantic, it occurs in areas influenced by the warm waters of the Gulf Stream and has been caught as far north as Prince Edward Island and as far south as Río de Janeiro. In the eastern Pacific, it ranges from Peru to Oregon.
Common dolphin are warmwater pelagic fish, occurring in the open ocean and usually found close to the surface, although in waters of great depth. They sometimes inhabit coastal waters and occasionally areas near piers, but in the open ocean they often concentrate around floating objects, especially buoys, driftwood, and seaweed lines or clusters. The young commonly frequent warm nearshore waters in sargassum beds or other flotsam. In developing countries, commercial fishermen may place floating bundles of bamboo reeds, cork planks,
and the like in the water to concentrate dolphin before seining or gillnetting commences.