The thing with seascapes...especially when approached with the goal of creating long exposures (as per the OP's suggestion) is that the highlights are usually somewhat transient. That foamy-white surf comes and goes over given areas, which means, happily in this case...that overall contrast buildup will not be as exacerbated by reciprocity failure as it would be in the case of, say, a waterfall - where the foamy/bubbly/white falling water is pretty much constant in a given area for the duration of a long exposure.