1970 photo of tuna boats at Seaport Village. San Diego was once the tuna capital of the world. From the 1930s until the late 1970s, it was the city's third-largest industry, behind the Navy and aerospace. Two of the three big tuna canning companies were here, and the waterfront was home to four canneries and many boats. Due to regulations, rising costs, environmental pressure associated with dolphins and other issues, all corporations had moved from the west coast by 1984.