The importance of fish size for price per kilo is studied using an inverse demand approach. Price per kilo in different size categories of the same species differs significantly. This means that the average price for a species may change due to e.g., high grading or a changing climate, which both have the potential to change the size composition of the catch. Estimates show that quantity flexibilities differ substantially across size and species, while scale flexibilities, in general, are close to homothetic. Holding total catch constant, an approximate 1% decrease in the largest size category and a corresponding increase in the smallest size category is estimated to reduce the value of an average week's catch by roughly 0.1–0.4%. The results imply that the effect of size on price is an important consideration when formulating regulations or policies to curb, for example, high grading.

JEL Codes: C51, Q11, Q22.