I have attached a pdf (of powerpoint slides) from the Spanish Ministry of Agriculture, Fisheries, and Food, which outlines the state of the fishing fleet and industry in Spain. Some of the slides (particularly some of the graphs/tables) are a bit difficult to understand, but there is some important data concerning the efforts Spain has been making to keep or build a sustainable fishery to meet their extremely high demand of fish:
*Aquaculture
*Artificial reefs
*Marine reserves (like closed areas)
*GPS tracking of boats
*Fishery inspections
There's also some useful data that outlines just how integral and large the fishing industry is in Spain:
*Spain produces nearly 1 million tons of fish and mollusks per year for human consumption, yet it imports more than twice the amount (in Euros) that it exports
*Spain also exports most of its catch to nations outside the EU
*Spain has several fishing agreements with countries across the globe (most heavily concentrated in Africa and South America) that allows the Spanish fleet to fish in every ocean on the planet