臺灣養殖魚類需求體系之研究—逆需求體系模型之應用

A Study of the Inverse Demand System of the Aquaculture Products in Taiwan

江福松(Fu-Sung Chiang) ； 李仲英(Jonq-Ying Lee)

《農業經濟半年刊》 68期 (2000/12) Pp. 1-25

https://doi.org/10.7086/JAE.200012.0001

摘要

本研究以國內主要的養殖魚類產品（吳郭魚、虱目魚、及其它養殖魚類產品）為研究對象，就其供給是相當地缺乏彈性的特性，應用五類逆需求體系模型進行實證分析並選擇出最適模型一組合逆需求體系，以建立國內養殖魚類産品之需求體系，並應用完全資訊最大概似估計方法進行參數之估計並求算出規模彈性及價格應用彈性。研究結果顯示，虱目魚、吳郭魚及其他魚種的自身價格應用估計值分別爲-0.664、-0.367和-0.015，顯示了虱目魚的可供消費量對養殖魚類產品的影響較其它兩類魚種來得顯著。又虱目魚的消費量對於吳郭魚和其它魚種的價格之影響分別為-0.302和-0.320。在規模彈性估計值方面，實證結果顯示當增加1％的養殖産品總消費量時，會導致吳郭魚的價格下跌0.96％；虱目魚的價格下跌1.171％；其他魚種的價格下跌0.671％。本研究結果顯示虱目魚在我國養殖魚類産品扮演重要的角色。

關鍵字

價格反應估計值 ； 組合逆需求體系 ； 養殖魚類產品

並列摘要

Based on both quantity and value production, aquaculture plays a very important role in Taiwan fishery production. This study used the demand theory to develop a demand system for the aquaculture products in Taiwan. The supply of the aquaculture products is quite inelastic, indicating an inverse demand system with prices dependent on quantities may be more appropriate than the direct demand system. This study examined and compared five inverse demand systems using monthly transaction data from the fish markets in Taiwan area. For the Taiwan's aquaculture products and for the modelling price-dependent demand, a synthetic model is more appropriate than other inverse demand models. Results of this study indicates that milkfish has the highest own-flexibility at -0.664, with tilapia and other aquaculture fishes having own-flexibilities of -0.367 and -0.015, respectively. In addition, a one-percent increase in aggregate quantity of aquaculture fishes would result in decreases in the normalized prices of 1.17%, 0.96% and 0.67% for milkfish, tilapia and other aquaculture fishes, respectively.

並列關鍵字

Price Flexibility Coefficients ； Synthetic Inverse Demand System ； Aquaculture Fish Products