The plight of the Thunnus thynnus thynnus - the Atlantic bluefin tuna - is stirring up the international fish business. Prized by the Japanese, fished by East Coast sportsmen, and the livelihood of the small New England fishing industry, the tuna suddenly has been judged in short supply. So short, in fact, that an international conference has invoked a two-year moratorium on fishing the species, beginning early in 1982.
The ban shouldn't affect US tuna prices, since Americans prefer the ''white albacore'' variety, but the impact on New England could be significant. Observers say the ban would cost the region's economy millions of dollars a year.
Jerry Abrams, owner of Fresh Water Fish in Boston, stands to lose $500,000 a year in bluefin business. Hardest hit will be the region's half dozen large bluefin fishing concerns. Also affected, says Mr. Abrams, are ''companies who sell bait and gear, trucking companies, and airlines.'' State tax revenues will be pinched, as well as motels, tourist-related industries, and charter boat companies conducting bluefin fishing trips for sports fishermen, observers predict.
Oddly enough, the bluefin ban will also affect the Rev. Sun Myung Moon's Unification Church, whose members operate a number of seafood-related businesses in Gloucester, Mass. The church's summer program, where its young members learn to fish for bluefin, stands to lose an estimated $100,000 a year.
In the United States, commercial bluefin fishing is comparatively small. Atlantic bluefin boats last year hauled in about 1,500 tons of bluefin during the three-month summer season, compared with the 250,000 tons of other tuna caught.
But the Japanese fish the Gulf of Mexico heavily for the bluefin tuna.New England fishers say Japan is to blame for overfishing the bluefin, since its boats haul in thousands of young school fish in the Gulf before they are able to spawn farther up the East Coast. In Japan, the dark meat fish is a highly valued delicacy, and is sold at premium prices.
The ban, invoked last month at a conference in the Canary Islands, was proposed by the US delegation to the International Commission for the Conservation of the Atlantic Tuna (ICCAT). The proposal was based on scientific data showing that the species already may be depleted beyond the point where it can replenish itself.
Although ICCAT members approved the ban, the commission does not have power to enforce the it. Some New England fishermen are concerned that Japan may ignore the ban and deplete tuna stocks anyway, while US boats sit at the docks.
In light of the scientific data, however, the ban was the only alternative, says Carmen Blondin, director of the National Marine Fisheries Service and a delegate to the 19-member-country ICCAT.
Regulations governing the ban have not been drafted yet, which gives the US bluefin industry is time to conduct its own study of tuna stocks. If the industry's study concurs with ICCAT's, fishers will probably go along with the ban in order to preserve future fishing stock.