Mahimahi (Dolphinfish) (Coryphaena hippurus)

• Population estimates are high, and no overfishing appears to be occurring.
• Mahimahi are one of the most common recreationally caught pelagic species in the U.S.
• Mahimahi is low in saturated fat and is a good source of vitamin B12, phosphorus, and potassium and a very good source of protein, niacin, vitamin B6, and selenium. For more on nutrition, see Nutrition Facts. (USDA)
• Between 66 million and 88 million pounds of mahimahi are delivered to the global market each year.

Sustainability Status

Biomass: There are no current estimates of biomass.
Overfishing: No (South Atlantic and Gulf); Unknown (Pacific)
Overfished: No (South Atlantic and Gulf); Unknown (Pacific)
Fishing and habitat: Any effects are minimal and temporary.
Bycatch: Regulations in the South Atlantic Fishery Management Council's Dolphin-Wahoo FMP for the Atlantic address requirements to reduce bycatch and mortality of bycatch. Longline vessels must also comply with sea turtle protection measures.
Aquaculture: There is currently no commercial aquaculture of mahi mahi in the U.S.

Science and Management

Dolphinfish from Maine to Florida are managed through the South Atlantic Fishery Management Council's (SAFMC) Dolphin Wahoo Fishery of the Atlantic Fishery Management Plan (FMP), in cooperation with the Mid-Atlantic and New England Councils. The SAFMC adopted a precautionary and risk-averse approach to management for this fishery. The goal of the FMP is to maintain current harvest levels and ensure that no new fisheries develop. Commercial fishing regulations include a 1.5 million pound (680 metric ton) cap on commercial landings, designations of essential fish habitat, minimum size limits, gear restrictions, and permitting requirements. The dolphin-wahoo fishery is also an important recreational fishery in the Atlantic. Recreational regulations include a minimum size limit, bag limit, and some permitting requirements.

Dolphinfish is also mentioned in the Fishery Management Plan (FMP) for the Coastal Migratory Pelagic Resources in the Gulf of Mexico and South Atlantic Region as part of the fishery, but it is not included in the management unit so no specific regulations apply.

On the Pacific coast of the U.S., dolphinfish are managed by the Pacific Fishery Management Council as part of the Highly Migratory Species category. Under the current FMP, there are no quotas, and the population is presumed to be healthy, given the large number of interactions with the species. The U.S. fishery only catches a small portion of the larger Pacific stock, and this fishery is mostly recreational.

A much larger fishery in the central and western Pacific is managed by the Western Pacific Fishery Management Council in their Pelagics FMP. The fishery includes commercial troll (rod and reel), handline, and longline fishing gears, with the latter two mostly targeting tunas. Recreational troll fishing is also important, though poorly quantified. To date, no management measures have been put in place specifically for this species because catch trends have indicated they are not necessary. Commercial landings in the region were about 1,200 metric tons (2.6 million pounds) in 2006.

Life History and Habitat

Life history, including information on the habitat, growth, feeding, and reproduction of a species, is important because it affects how a fishery is managed. The life history of dolphinfish suggests the species may be able to withstand a relatively high rate of exploitation.

• Geographic range: In tropical and subtropical waters of all oceans
• Habitat: Oceanic pelagic fish; generally restricted to waters warmer than 68 degrees Fahrenheit
• Life span: Short, maximum is 5 years; males live longer than females
• Food: Dolphinfish are voracious predators and feed in surface water during the day. They eat a wide variety of species including small pelagic species (living in the water column) such as flying fish, halfbeaks, man-o-war fish, Sargassum fish, and rough triggerfish, juveniles of large pelagic species (tunas, billfish, jacks, and dolphin), and pelagic larvae of nearshore, bottom-living species (flying gurnards, triggerfish, pufferfish, and grunts). Dolphinfish also eat invertebrates such as cephalopods (octopus, squid, etc.), mysids (small, shrimp-like creatures), and scyphozoans (jellyfish), which suggests they are essentially non-selective, opportunistic foragers.
• Growth rate: Growth is extremely rapid. Specific rates vary among regions and are sensitive to water temperatures.
• Maximum size: The largest dolphinfish length reported is almost 7 feet; the maximum weight reported is 88 pounds.
• Reaches reproductive maturity: Dolphinfish reach maturity at 4 to 5 months.
• Reproduction: Dolphinfish are prolific spawners, reproducing repeatedly. Recent research suggests that they may spawn every 2 to 3 days for the duration of the entire spawning season, perhaps even year round. Females may have 33,000 to 66,000 eggs per spawning event.
• Spawning season: Spawning is thought to occur year round in waters with temperatures above 75 degrees Fahrenheit, but peaks vary with latitude. For example, in the Florida current, spawning occurs from November through July and during June and July in the Gulf Stream near North Carolina. Off southern California and Mexico, peak spawning occurs from August to September.
• Spawning grounds: In the central North Pacific, dolphinfish appear to spawn in waters less than 50 nautical miles from islands and banks. Off the continents, they appear to spawn on the continental shelf. There does not seem to any spawning in the open ocean in the Pacific. In the Atlantic spawning occurs under Sargassum patches.
• Migrations: Young dolphinfish school, but older individuals are more solitary. Adults make seasonal north-south migrations.
• Predators: Predators include large tuna, rough toothed dolphin, marlin, sailfish, and swordfish (particularly preying on juveniles).
• Commercial or recreational interest: Both
• Distinguishing characteristics: Bright turquoise, green, and yellow patterns; can be distinguished from the pompano dolphin by its 55 to 66 dorsal fin rays and a very wide, square tooth patch on the tongue.

Role in the Ecosystem

Dolphinfish are called apex predators, a designation that means they feed high on the food chain while having only a few predators. These fish are abundant and wide ranging throughout the tropical and subtropical oceans. They support important commercial, artisanal, and recreational fisheries around the world. Dolphinfish are also a large component of the bycatch of the tuna purse-seine and longline fisheries in the Pacific. They are commonly found near natural and artificial floating objects, a trait which facilitates their capture.

Larger males seem to prefer open ocean habitat while females and smaller males remain associated with Sargassum (in the Atlantic) and floating debris. It has been theorized that males are more active feeders than females and are substantially heavier, so a greater amount of food is required to sustain their metabolism, leading to more voracious feeding. This theory holds that the open ocean habitat provides larger prey for the larger male dolphinfish.

Additional Information

Market name: Mahimahi
Vernacular names: Dorado, Common dolphinfish
Mahimahi is also the market name for Pompano dolphin (Coryphaena equiselis)

Biomass

Biomass refers to the amount of dolphinfish in the ocean. Scientists cannot collect and weigh every single fish to determine biomass, so they use models to estimate it instead. These biomass estimates can help determine if a stock is being fished too heavily or if it may be able to tolerate more fishing pressure. Managers can then make appropriate changes in the regulations of the fishery. There are no current reliable estimates of biomass, but the life history of dolphinfish suggests the species may be able to withstand a relatively high rate of exploitation. Both Atlantic and Pacific populations are presumed to be healthy.

Landings

Landings refer to the amount of catch that is brought to land.

Note: The landings presented are domestic commercial landings.

Biomass and Landings

Are landings and biomass related? Landings are dependent on biomass, management measures in the fishery, and fishing effort. Unfortunately, there are no current reliable estimates of dolphinfish biomass to compare with landings data.

Data sources:
Landings from NOAA's National Marine Fisheries Service (NMFS) Annual Commercial Landing Statistics using "DOLPHINFISH" as species and "ATLANTIC AND GULF" and "PACIFIC" as State

Important Dates

Late 1970s – Landings increase in the northeast from Maine to Virginia
1986 – Western Pacific Fishery Management Council's Preliminary Pelagics FMP revised to include dolphinfish. Final FMP implemented in 1987.
1994 - 1997 – Combined landings from all sectors of the dolphinfish and wahoo fishery in the Atlantic reach an all time high for the management unit, with the highest landings being reached in 1995
1995 – Commercial landings in the Atlantic exceed 2.2 million pounds/998 metric tons (doubling the 1 million pound/454 metric ton landings in 1989)
1999 – Total recreational harvest accounts for 91% of the total U.S. harvest
2002 – SAFMC proposes a revised FMP for Pelagic Sargassum Habitat to protect Sargassum as an essential fish habitat by prohibiting all harvest and possession of Sargassum in certain areas and limiting harvest all together
2004 – South Atlantic Fishery Management Council's Dolphin Wahoo FMP implemented
2004 – Pacific Fisheries Management Council's Highly Migratory Species FMP partially approved

Notes and Links

General Information:
NOAA's National Marine Fisheries Service (NMFS) Sustainability Species Identification for dolphinfish

South Atlantic Fishery Management Council (SAFMC) summary of dolphinfish and related regulations

NOAA Southeast Fisheries Science Center Summary table of dolphinfish

Fishery Management:
SAFMC summary of dolphinfish management and link to Fishery Management Plan for the Dolphin and Wahoo Fishery of the Atlantic (2003)

SAFMC and GMFMC Coastal Migratory Pelagics of the South Atlantic and Gulf of Mexico Fishery Management Plan

Pacific Fisheries Management Council Highly Migratory Species Fisheries Management Plan

Western Pacific Fishery Management Council's Pelagics FMP