This work is part of the SUCCESS project (Work Package 4: Competitiveness and sustainability of European fisheries and Aquaculture sectors) funded by the EC (H2020, GA 635188). The dynamics of the value chain in eight different species at the Spanish market has been studied using price integration methodologies. Cases of market delimitation cover substitution across wild and farmed species and across imports and domestic production of the same species. Price transmission is tested in domestic and international value chains of farmed and wild species. Results from the market delimitation models show high level of differentiation across production systems, however, there is keen competition across domestic production and imports of the same species. On regard price transmission producers are more likely to be able to transfer their costs downstream in the value chain when they operate a differentiated product, concentrate large volumes of supply and participate as exporters in the international markets. Upstream price transmission, in contrast, is more frequent when the harvesting industry is fragmented in companies operating small volumes and the product is not differentiated.