If the wood is 'shrinking' such that you see the tongue or shrinking such that you see China, you may still have this problem.
Sure, if you want to hear it, you can fill the gaps with epoxy wood filler. I, personally, wouldn't stand behind the job. How 'bout finding some other Taverns that have finished floors. Talk to their owners about the age of their 'new floor' and what they did to fix this-and-that. In short, no matter what I or anyone else says, go with what works. If you can control the environment, you're in a good situation all the way around.