Bodies of water like lakes yes. Stormy seas would refer to the state of the sea (i.e. wavy, amount of unrest). An ocean is always an ocean and California is onl

Bodies of water like lakes yes. Stormy seas would refer to the state of the sea (i.e. wavy, amount of unrest). An ocean is always an ocean and California is only connected to one of those. Coastal waters is clearly the correct term as they didn't do measurements across the whole Pacific (didn't read the source articles linked though), only around the coastline of California. So either "California coast" or rather "California coastal waters", since the article is talking about the watery part of the coast, not the "landy" part.