First-sale prices of fish respond to both local and global drivers, and artisanal fishermen are often considered as price-acceptors due to their limited capacity to influence them, a key issue for their survival and value added creation. However, in artisanal fisheries, the frequent lack of data hinders us from understanding the complex mechanism of first-sale price formation (considering those special circumstances that often differentiate them from industrial fisheries, such us high product quality, seasonality and low volume of landings, co-management structures, local labels, etc.), as well as to evaluate the impact that local-regional management measures may be having on these prices. This paper models first-sale prices of common octopus in the Asturias fish markets (Northern region of Spain), using for the first time detailed local data concerning its fishing and marketing since 2009. The objectives of the econometric models used and compared are (1) to understand the local and supra-regional mechanisms that explain first-sale prices, (2) to measure the importance of local variables (that can be locally managed), and (3) to estimate the impacts of co-management measures aimed at the economic-environmental sustainability of the resource (octopus management plan of the western artisanal fleet and MSC eco-certification of part of the landings).