Balancing Dark Foreground with Brighter Sky at Night

Last night I was taking some beach shots and I was using the TTL spot meter (taking reading from grey area of sky) panning back and taking shot. I was focusing on the sun lit area of the water and some parts of the sky.

The sky was nicely exposed, but my foreground was quite a bit darker than it should have been. I was shooting at ISO 100 on aperture value setting F8 and f16.

Is there anything I can do to get a better balance, or is this a job I do at the RAW conversion/Photoshop stage?

This is a perfect example of where one could use a graduated neutral density (GND) camera lens filter. Another option would be to take two photographs in RAW mode-- one exposed for the sky and the other for the foreground--then replicate the effect of the GND filter in Photoshop.

Either way, both of these techniques will require an even longer exposure than the (presumably) long exposure you were using for the night shot.