Out of resources, what do?!

I was in a diplomacy game on a custom Island chain map where I ended up being a sort of puppet state to my biggest neighbor who had the opportunity to expand through war. I ran out of trees, rocks, gold, berry bushes and fish on my island, and then ended up joining my distant allies and betraying the big empire in a 3 vs 1 war (they didn't really have troops of attention to spare) so I kicked them off my Island.

But the problem was that even though my Island was no longer partially occupied by the enemy, it was devoid of resources.

I did trade some using the market but there were now walls between me and the people I was trading with and the seas were no longer completely safe either. Though a lot safer and more practical than on land. The problem is that their dock got clogged up with fishing boats of a neutral player with whom I shared a sea border and a colony Island.

So is the only real option if there are no relics to trade or is there some way to get resources renewably??