this definitely depends on perspective... or at least timing and location. i have seen brown ocean waves with a white froth when the wave breaks just one state east of mine. due to this and year after year of reports of used hypodermic needles washing on shore, i prefer the actual blue waters of the ocean at least 2 states south of here.all people will agree that the image of "ocean" ussually corresponds with that of "blue". Therefore Oceans are blue.
a particular "hit" television show doesn't help much, either.