Seaweed farming is an important part of the economy , with two major species ''Eucheuma alcarezii'' and ''Eucheuma spinosium'' introduced to the local lagoons from the Philippines in 1977. It competes with collection of the black-lipped pearl oyster (''Pinctada margaritifera'') and shellfish, which are dominated by the strombid gastropod (''Strombus luhuanus'') and Anadara cockles (''Anadara uropigimelana''), whereas the stocks of the giant clam (''Tridacna gigas'') have been largely exhausted.