An interesting question. I'm certain I don't have a complete answer, but I'll comment with my opinion.
Any luxury item, whether it be natural or cultured pearls are both directly and indirectly proportional to the world economy. Natural pearl collection is merely a tiny niche in the overall pearl marketplace. Those who want them, specifically want them, therefore ought to pay premium prices. When you find ways to lower that premium to the end user, they'll move better to everyone's advantage.
When the price of gold is high, the cost of finished products is high. Issues such as these undoubtedly cause wholesalers and manufacturers to look for better deals, meaning paying less for gems or other parts.
When the price of fuel drops like has recently, it's good for pearl farmers and wholesalers etc., but it takes several years to realize. After all, cultured pearls need to grow a while. Pearls from the last few years were produced with high fuel costs. Natural pearls on the other hand, go from shell to market rather quickly, so it's difficult to parallel them with cultured pearls in the short term.
Natural pearl harvesters today enjoy reduced fuel costs, even though other costs continue to rise. This point is not lost on wholesalers looking to cut corners on raw materials nor consumers looking for a bargain. The price of gold dropped to $1200 USD in December, but is trickling upwards again. Therefore, it's harder to negotiate an adjustment in return.
Again, I'm not sure what the answer is, but fuel and gold certainly play into the equation. All I can suggest is finding a balancing point between hoarding when the market is low and selling when the market demands it. The disadvantage is cash flow, but the advantage is greater matching... which increases value and better pricing.
Good luck, good diving and be safe!