Roya Eshraghi Samani - Department of Agricultural Management, Ilam Branch, Islamic Azad University Ilam, Iran.

The importance of breedingaquatic animals can be discussed in different aspects. Among the most important aspects are the increasing population, destruction of renewable natural resources and too much exploitation of sea stores. This study investigates the production structure of breeding salmon in the province of Lorestan. For this purpose, using dual theory and compositional statistics,time series-cross section of (2008-2014) related to 25 fields of salmon breeding, Translog cost function and derived demand functions are simultaneously estimated through an iterative seemingly irrelevant system of equations. The results of the study suggest that salmon breeding industry s technology of production in the region of study is non-homothetic and the share of production factorscosts changes due to scale change of production.The technology of generating this product was work-saving and money-saving and the share of food inputs cost and young salmon increases as production scale increases. Also return to production scale is increasing in this industry. Moreover, except for the complementary relationshipbetween young salmon inputandlabor and food inputs, the relation between other inputsis substitution.Own-price elasticity indicatestheinelasticity of labor, money and food inputs demand to their price changing in the industry of breeding salmon. Also based on the computed cross elasticities of price, the cross elasticity of food to price change of other inputs is less than the cross elasticity of other inputs to the price change of food input.

Production structure, economics ofscale, input substitution, cost function