In Asid Gulf (2417 km2), Masbate (Philippines), five major commercially important pectinids are exploited for foreign and domestic markets.The species exploited are the most diverse and production volume the highest from any single area in the Philippines.Bulk of its production (1-5 mt adductor muscle/day) is primarily Decatopecten striatus constituting about 60% of the total annual harvest.Toward the objective of managing the scallop resource in the gulf, biological information is vital to provide scientific basis for a sustainable harvest policy.