In an effort to reduce the number of giant bluefin tuna killed by fishing fleets, the U.S. is putting out new rules about commercial fishing in the Gulf of Mexico and parts of the western Atlantic. The rules have special protections for giant bluefin — fish that have grown to 81 inches or more.

The new requirements were recently published by the National Oceanic and Atmospheric Administration, in a nearly 750-page amendment to its management plan. The agency hopes the changes will help rebuild the tuna population and improve data it gets from fishing vessels.

As NPR's Christopher Joyce reports for our Newscast unit, commercial fleets in the Gulf cannot target giant bluefin tuna, whose numbers have fallen since the 1970s. The Gulf is of crucial importance, as it is the fish's breeding ground.

"But fishing fleets can harvest other types of tuna and large fish using long-lines. These are lines loaded with hooks that float below the surface and can run 30 miles long. They often accidentally hook and kill giant bluefin tuna."The new rules will lower the allowable number of these accidental killings, called 'by-catch.' They also will require video cameras on fishing vessels to record full time what's being caught. The rules cover long-line fishing in the Gulf and parts of the Atlantic coast."

The new rules were welcomed by the Pew Charitable Trusts' ocean conservation unit, with director Lee Crockett saying, "NOAA Fisheries deserves great praise for significantly increasing protections for bluefin while allowing fishing for yellowfin tuna and swordfish to continue."

The group also lists some of the things that set the bluefin apart:

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