Reasonable annual limits, monthly limits, zone limits, modified possession limits (don't necessarily have to be tied to a set # of daily limits, could simply be X # of a given species), etc - lots of available tools.
Ziggy, you use the example of Interior lakes but your argument about over harvesting in that context isn't strong as each lake has different regs to ensure this doesn't happen, regardless of possession limits. Most of the quality waters are 100% catch and release, while others have very limited daily harvest allowed - i.e. not somewhere someone is going to camp out and fill freezer after freezer if just one fish per day can be harvested. Lakes with larger daily limits typically are nutrient limited and thus have smaller trout competing for limited groceries so harvest is encouraged.
Back to the saltwater issue, a monthly limit would still allow the local angler to access plenty of fish over the course of the fishing season, as would limits by fishing zone (whether monthly or annual). Such approaches wouldn't curb the sport side of it, which I think everyone agrees on should be open and the main focus for all rec anglers, while approaching more equitable sharing of the total harvest between all anglers accessing any particular fishery.
Counter argument, of course, is that we're already over regulated and they're damn confusing to boot - which is a very valid argument. Having said that, pretty clear from this thread travelling anglers who invest a lot of $'s into the rec fishing economy definitely feel an unfair disparity exists in the current possession regs between local and travelling anglers - so worth sussing out.
Ukee