The formation of ex-vessel price of two important Mediterranean fisheries products (hake and red shrimp) was studied through an inverse demand approach, using data from the Catalonia bottom trawl fishery (NW Mediterranean). In both species, the landings by commercial category (proxy for fish size) and total landings determined the daily price fetched at the auction, as summarized by the quantity and scale coefficients (“flexibilities”) derived from the inverse demand model. In general, quantity flexibilities were between −0.1 and − 0.6, indicating that a 1% increase in the landings of one category (for a given species) would reduce the average daily ex-vessel price by 0.1–0.6%. Scale flexibilities were generally lower than − 1, showing that these species tend to behave non-homothetically, especially for the large size categories. These results imply that changes to the quantities landed and the size composition of landings, resulting for instance from fisheries management measures, will affect sale prices. Simulations of sale price for scenarios of reduced landings, in line with fishing at maximum sustainable levels, showed that losses in revenue would be much less than the losses projected with constant prices. Similarly, higher landings resulting from rebuilt stocks would yield lower revenues from these stocks because of the generally negative flexibilities.

使用来自加泰罗尼亚底拖网渔业（地中海西北地区）的数据，通过逆需求方法研究了两种重要的地中海渔业产品（无须鳕和红虾）的离岸价格形成。在这两个物种中，商业类别的上岸量（代表鱼的大小）和总上岸量决定了拍卖中的每日价格，由逆需求模型得出的数量和规模系数（“灵活性”）总结。一般而言，数量灵活性介于 -0.1 和 - 0.6 之间，表明一个类别（对于给定物种）的上岸量增加 1% 将使每日平均离船价格降低 0.1-0.6%。尺度灵活性通常低于 - 1，表明这些物种往往表现出非同质性，特别是对于大尺寸类别。这些结果意味着上岸数量和上岸数量组成的变化，例如渔业管理措施，将影响销售价格。对上岸量减少情景的销售价格模拟，与最大可持续捕捞水平一致，表明收入损失将远小于以不变价格预测的损失。同样，重建库存导致的上岸量增加会导致这些库存的收入减少，因为它们通常具有负面的灵活性。表明收入损失将远小于以不变价格预测的损失。同样，重建库存导致的上岸量增加会导致这些库存的收入减少，因为它们通常具有负面的灵活性。表明收入损失将远小于以不变价格预测的损失。同样，重建库存导致的上岸量增加会导致这些库存的收入减少，因为它们通常具有负面的灵活性。