Dolphin Fish (Mahi-Mahi) Facts

Bull dolphin fish or mahi-mahi
Bull dolphin fish or mahi-mahi. Stephen Frink / Getty Images

The dolphin fish is not a dolphin. Unlike dolphins, which are mammals, dolphin fish are a type of ray-finned fish. The dolphin fish most likely got its confusing common name because it was previously classified in the genus Dolfyn. It also has a melon-shaped head, much like that of a true dolphin. In the modern classification system, the fish belongs to the genus Coryphaena.

If a restaurant menu includes "dolphin," it's referring to the dolphin fish, not the mammal. Some restaurants use the alternative names mahi-mahi and pompano to prevent confusion.

Fast Facts: Dolphin Fish

  • Scientific Name: Coryphaena hippurus (common dolphin fish); Coryphaena equiselis (pompano dolphin fish)
  • Other Names: Dolphinfish, dolphin, mahi-mahi, dorado, pompano
  • Distinguishing Features: Brilliantly colored fish with single dorsal fin spanning the length of the body; males have protruding foreheads
  • Average Size: 1 meter in length and up to 40 kilograms (88 lb) weight
  • Diet: Carnivorous
  • Life Span: Up to 5 years, but usually less than 2 years
  • Habitat: Temperate, subtropical, and tropical oceans worldwide
  • Conservation Status: Least Concern
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Perciformes
  • Family: Coryphaenidae
  • Fun Fact: The dolphin fish is a very fast swimmer, reaching speeds of nearly 60 mph.

Description

There are two species of dolphin fish. The common dolphin fish (also known as mahi-mahi or dorado) is C. hippurus. The other species of dolphin fish is C. equiselis, which is also known as the pompano dolphin fish.

Both species in the genus Coryphaena have a compressed head and single dorsal fin running the full length of the body. Both the anal and caudal fins are sharply concave. A mature male (bull) has a prominent protruding forehead, while a female has a rounded head. Mature females are smaller than males. Their long, slender bodies are well-suited to fast swimming. Mahi-mahi swim up to 50 knots (92.6 kph or 57.5 mph).

Pompano dolphin fish are sometimes mistaken for juvenile common dolphin fish or mahi-mahi because they are small, reaching a maximum length of 127 centimeters (50 in). Pompano dolphin fish are bright blue-green with silver-gold sides. The fish fade in color to dull gray-green when they die.

A typical mahi-mahi reaches a length of one meter and a weight of 7 to 13 kg (15 to 29 lb), but fish over 18 kg (40 lb) have been caught. These fish are brilliantly colored in shades of blue, green, and gold. Pectoral fins are iridescent blue, the back is green and blue, while flanks are silvery-gold. Some individuals sport red spots. Out of water, the fish appears golden (giving rise to the name dorado). Upon death, color fades to yellowish-gray.

Distribution

Both species of dolphin fish are migratory. The common dolphin fish prefers coastal and open water from sea level to a depth of 85 meters in temperate, subtropical, and tropical oceans worldwide. The pompano dolphin fish range overlaps that of the common dolphin fish, but it usually lives in the open ocean and occurs as deep as 119 meters. The fish form schools and tend to congregate in seaweed and under floating objects, including buoys and boats.

Diet and Predators

Dolphin fish are carnivores that prey upon zooplankton, squid, crustaceans, and smaller fish. The fish is prey to other large oceanic predators, including billfish and sharks. Both species are important for commercial and sports fishing. The fish are generally considered safe to eat, but they are moderately contaminated with mercury and can serve as a vector for ciguatera poisoning.

Reproduction and Life Cycle

Dolphin fish grow and mature very quickly. Fish reach maturity between 4 and 5 months of age and start spawning when they reach a length of about 20 centimeters. Spawning occurs throughout the year when water currents are warm. Females spawn two to three times each year, producing 80,000 to a million eggs each time. Pompano dolphin fish have a life span of up to 3 to 4 years, but most live less than 2 years. Mahi-mahi live up to 5 years, but rarely exceed 4 years.

Conservation Status

Both the common dolphin fish and pompano dolphin fish are categorized as "least concern" on the IUCN Red List. Its population is stable. However, the fish face threats from declining habitat quality. The species has high commercial value and is extensively harvested. Many countries have imposed bag limits and size limits to support sustainable fishing.

Sources

  • Collette, B., Acero, A., Amorim, A.F., Boustany, A., Canales Ramirez, C., Cardenas, G., Carpenter, K.E., de Oliveira Leite Jr., N., Di Natale, A., Fox, W., Fredou, F.L., Graves, J., Viera Hazin, F.H., Juan Jorda, M., Minte Vera, C., Miyabe, N., Montano Cruz, R., Nelson, R., Oxenford, H., Schaefer, K., Serra, R., Sun, C., Teixeira Lessa, R.P., Pires Ferreira Travassos, P.E., Uozumi, Y. & Yanez, E. 2011. Coryphaena hippurusThe IUCN Red List of Threatened Species 2011: e.T154712A4614989. 
  • Gibbs, R.H., Jr. and Collette, B.B. 1959. On the identification, distribution, and biology of the dolphins, Coryphaena hippurus and C. equiselisBulletin of Marine Science 9(2): 117-152.
  • Potoschi, A., O. Reñones and L. Cannizzaro. 1999. Sexual development, maturity and reproduction of dolphinfish (Coryphaena hippurus) in the western and central Mediterranean.: Sci. Mar. 63(3-4):367-372.
  • Sakamoto, R. and Kojima, S. 1999. Review of dolphinfish biological and fishing data in Japanese waters. Science Marine 63(3-4): 375-385.
  • Schwenke, K.L. and Buckel, J.A. 2008. Age, growth, and reproduction of dolphinfish (Coryphaena hippurus) caught off the coast of North Carolina. Fish. Bull. 106: 82-92.