FISHERY IMPACTS ON STOCK | HABITAT IMPACTS | BYCATCH | MANAGEMENT EFFECTIVENESS
Fishery Impacts on Stock
Mahi mahi, found worldwide in tropical and subtropical waters, are prolific spawners and have extremely rapid growth, which helps them remain fairly resilient to fishing pressure. However, since mahi mahi in the Atlantic are drawn to a floating brown alga that hides food, they often accidentally eat all kinds of garbage tangled in the alga. Currently mahi mahi in the Atlantic are not being overfished although the population status in the Pacific is unknown, according to the National Marine Fisheries Service.
In Hawaii, mahi mahi are caught using various hook and line gear, including trolls, which have minimal environmental impact on the seafloor. Surface longline gear and purse seines used in the fishery also avoid seafloor damage.
Extent of Bycatch
Purse seines that catch mahi mahi while targeting tuna can also catch sharks and juvenile tuna. According to the Blue Ocean Institute, the longlines used to catch mahi mahi have high shark bycatch rates and efforts have not been undertaken yet to reduce them. Bycatch from longlines also includes sea turtles, marine mammals, and sea birds. The largest mahi mahi fishery is near Ecuador, where fishermen use handlines that have minimal bycatch.
Management plans have been adopted in Ecuador but there are none yet in Costa Rica, Guatemala or Peru. All of these countries’ mahi mahi fisheries are engaged in Fishery Improvement Projects, according to the Monterey Bay Aquarium’s Seafood Watch. Mahi mahi in the U.S. Atlantic is managed by the South Atlantic Fishery Management Council, which has size limits set on the fish in Florida, Georgia and South Carolina. Fishery managers in the South Atlantic and Gulf of Mexico removed mahi mahi from the region’s fishery management plan although they can still collect catch data. In the Pacific, general management measures apply to the fisheries that target the fish. Overall there is a lack of comprehensive stock assessment data for mahi mahi and no plans currently exist to scientifically monitor or research the stock in the future.