9. Farming Costs and Benefits, Marketing Details, Investment Risks: The Case of Octopus vulgaris in Spain

The common octopus, Octopus vulgaris, is an important candidate for marine aquaculture, with optimum conditions for ongrowing such as high growth rate, easy adaptation to captivity and feeding conditions and high market value. The available technology for the culture of the whole life cycle is scarce and has only been achieved on a laboratory scale because there is no commercial diet available. For this reason, the production system is based on the capture of wild subadults, which are kept in different types of cages and fed with species of low commercial value. From the economic point of view, work to date concentrates on cost accounting of octopus ongrowing in floating cages in protected areas, open sea or land-based tanks. Global results show that the production cost in land-based tanks is generally higher than when fattening in sea cages, which may benefit the scale economy. The highest costs in decreasing order correspond to feeding, fixed assets, subadults purchasing and labour costs. Proper development of this activity requires solving two limiting issues: mass production of subadults at an industrial level and a suitable commercial diet.