Mahi-Mahi

Mahi-mahi, aka "dolphinfish," are found worldwide in tropical and subtropical waters. They are prolific spawners and have extremely rapid growth, which helps them remain moderately resilient to fishing pressure. The stock status of mahi-mahi in the Atlantic Ocean is stable although a full assessment had not been conducted, according to a 2016 Seafood Watch report. Mahi-mahi are also assumed to be stable in the U.S. Pacific. Population data for the Western Atlantic and Gulf of Mexico are outdated. Stock status is also lacking for mahi-mahi caught in the Indian Ocean and throughout the Pacific Ocean. 

Hook and line gear is mainly used to target mahi-mahi in the U.S. Atlantic, which has minimal contact with the ocean floor. In the U.S. Pacific, mahi-mahi are primarily caught using troll and handlines that do not adversely affect the seafloor substrate, according to Seafood Watch. The surface-set pelagic longline and purse seine gear used to target the fish around the world also has a minimal impact on the ocean habitat. Free-floating algae in the Atlantic called sargassum is an essential mahi-mahi habitat that became protected by fishery managers in 2003. 

Bycatch is a major issue with mahi-mahi. The pelagic longline fisheries targeting the fish throughout the world are known to incidentally catch sharks, sea birds, and sea turtles. Some bycatch mitigation measures have been applied to fisheries in the United States, Canada, and Ecuador. Longline mahi-mahi fisheries in Guatemala, Costa Rica, Peru, Indonesia, Panama, and Taiwan catch sensitive species, but lack measures to address bycatch, prompting Seafood Watch to give them red ratings for that criterion. In the South Atlantic, longlines are known to interact with white-chinned petrel, leatherback turtles, loggerhead turtles, yellow-nosed albatross, and wandering albatross, which all have critical fishing mortality. A 2016 Seafood Watch report pointed to concern over bycatch that included sea turtles, silky and oceanic white tip sharks in the Atlantic Ocean floating object purse seine fisheries targeting mahi-mahi. Handline and troll gear is more selective and allows fishermen to release incidental catches quickly.

Mahi-mahi fishery management varies widely by country and region. The U.S. Atlantic mahi-mahi stock is managed by NOAA Fisheries and the South Atlantic Fishery Management Council in cooperation with the Mid-Atlantic and New England Fishery Management Councils. Measures include permit requirements, and size limits set on the fish in Florida, Georgia and South Carolina.

On the U.S. West Coast, mahi-mahi are managed by NOAA Fisheries and the Pacific Fishery Management Council under a fishery management plan for highly migratory species. Although there are no measures specific to mahi-mahi, fishermen in the longline fishery there must have permits, log books, carry a vessel monitoring system, and allow onboard observers from NOAA. Owners and operators are required to attend annual workshops about protected species. Seafood Watch called mahi-mahi management in the United States moderately effective overall.

In Canada, the stocks are managed by Fisheries and Oceans Canada. A 2016 Seafood Watch report called Canadian management for bycatch species insufficient compared to the United States. Although the mahi-mahi longline fishery in Ecuador has infrequent bycatch, Seafood Watch gave the country a good alternative rating for having a management framework in place to address the impact on mahi-mahi stocks and species of concern.

Other mahi-mahi fisheries lack effective management. Panama has some bycatch measures in place, such as voluntary circle hooks and a national plan for shark preservation, but Seafood Watch called them inefficient to protect vulnerable species. In addition, as of 2016, there were no harvest control rules. Indonesia lacks bycatch management measures for mahi-mahi, and Seafood Watch expressed concern over compliance with other management measures in place there. In Taiwan, although mahi-mahi is managed by the Fisheries Authority of the Council of Agriculture, there are currently no measures. Costa Rica, Guatemala and Peru are engaged in a fishery improvement project, but lack fishery management plans for mahi-mahi.