日本鮪魚需求及對臺灣輸日冷凍鮪魚需求之研究

Abstract

我國超低溫鮪釣漁業在近幾年發展迅速，其漁獲物絕大多數外銷日本作生魚片使用，對日本市場的依賴性極重。所以日本市場的變動將會對我國鮪漁業的經營與發展有很大影響。本研究主要目的在於透過相關資料蒐集，對日本鮪魚需求進行分析與研究，其結果將可作為政府決策及業者經營之參考，以決定未來發展之道。 本研究利用經濟理論之需求體系(demand system)，假設鮪魚需求量為鮪魚價格、其他鮮魚、牛肉、豬肉及雞肉等替代品價格及所得之函數，資料經過相對變動率的轉換，求得鮪魚之需求函數： q1＝-0.0136-1.0289p1+0.4888 p2-0.4054 p3-0.072 p4-0.2058 p5+1.2234x 鮪魚需求量（鮪魚）（鮮魚）（牛肉）（豬肉）（雞肉）（所得） 顯示鮪魚價格及所得對其需求量均有顯著影響，其他肉品則不具替代性。同時，鮪魚本身價格彈性及所得彈性都高，顯示其需求面之潛力。 其次，利用單一方程式雙對數分析日本冷凍市場中主要供應國家鮪魚的需求模型。在同一價格下，冷凍大目鮪需求量之大小依序為日本、臺灣、其他國家及韓國。對臺灣而言，冷凍大目鮪供給量從1981年八千公噸穩定成長到1993年三萬公噸，價格也逐年提高，可能係品質提高使得售價提高，需求曲線有上移的趨勢。冷凍黃鰭鮪需求則以臺灣產品的所得彈性及價格彈性最高。臺灣及日本的黃鰭鮪間具有替代性。對臺灣而言，歷年輸日黃鰭鮪價格有下降的趨勢，而量則逐年成長，歷年的實際值大都在需求曲線上變動。

The Taiwanese tuna deep longline fisheries developed rapidly these years, and most of the catches were exported to Japan for sashimi. Therefore, the fluctuation of Japanese market will influence Taiwanese tuna fisheries. The objectives of this study are to analyze the demand of tuna in Japan, and offer market strategies for government and fishermen. Under the demand theory, the study assumes that the demand quantity of tuna is the function of the price of tuna, other fish, beef, pork, chicken, and income. All variables are transformed to the forms of change rate. The demand function of tuna is following: q1=-0.0136-1.0289p1+0.4888p2-0.4054p3-0.072p4-0.2058 p5+1.2234x tuna demand (tuna) (fish) (beef) (pork) (chicken)(income) The price of tuna and income have significant effects on tuna demand, but the prices of other meats don’t. At the same time, the high values of price elasticity and income elasticity of tuna show the demand potential in Japan. Then, the single equation of double logarithm were used to analyze the demand of the principal supplying countries’ frozen tuna in Japan. Under the same price, the demand quantities of frozen bigeye are: Japan, Taiwan, other countries and South Korea in order. The Supplied quantities of bigeye of Taiwan were 8 thousand tons in 1981 and 30 thousand tons in 1993, And the price increased yearly. The result may comes from the upgrade of tuna quality so that the price increased and the demand curve is upward. Concerning the demand quantities of frozen yellowfin tune, the price elasticity and income elasticity of Taiwan are the highest, the tuna of Japan and the tuna of Taiwan show substitution. The prices of Taiwanese yellowfin tuna decreased and the quantities increased these years. The observed values scatter on the theoretical demand curve well.