The Gulf of Lion is part of the Mediterranean Sea and lies of the coast of Southern France up to the Spanish region of Catalonia. It has a surface area of around 15,000 km2 and borders the Ligurian Sea to the east and the Balearic Sea to the southwest. The current name of the gulf first appeared in the 13th century, and it could have been referring to the fact that the waters were considered as violent and dangerous as a lion. The gulf is an important fishery, with the European hake as most important catch. It also borders Marseille, and important port; and Toulon, a major naval base.