世界虾类年产量近20年来,一直在逐年增加(表1)。五十年代的虾类产量不足50万吨;六十年代平均年产量为67万吨,其中后五年(平均了8.3万吨)较前四年(52.9万吨)增长了48%;七十年代以来,产量急剧上升,年产量突破了100万吨,平均年产量为121.9万吨(1977年高达144.6万吨),七十年代较六十年代增长了81.9%。虾类产量逐年稳定增长的主要原因是国际市场对于对虾类的需要 The annual production of shrimp in the world has been increasing year by year for nearly 20 years (Table 1). The shrimp production in the 1950s was less than 500,000 tons; the average annual production in the 1960s was 670,000 tons, an increase of 48% over the last five years (an average of 83,000 tons) over the previous four years (529,000 tons); seventy Since the beginning of the 1990s, the output has risen sharply. The annual output has exceeded 1 million tons. The average annual output has reached 1,219,000 tons (up to 1,446,000 tons in 1977) and 81.9% in the 1970s compared to the 1960s. The main reason for the steady increase of shrimp production year by year is the need of shrimp in the international market