(CNN) -- The spice trade put Zanzibar on the map. Lucrative spices like cardamom, cinnamon and cloves have brought traders from around the world to the Tanzanian island since the 19th century.
But many farmers now worry that the industry that gave Zanzibar its nickname -- Spice Island -- could be a thing of the past.
The clove season has now ended in Zanzibar and farmer Salum Mussa is preparing his land for a new crop -- rice.
"There's no profit in cloves," Mussa said. "The main problem is the price. Sometimes it is up, sometimes it is down. We are heartbroken."
Zanzibar once monopolized the trade in cloves, which are still rated as the world's best. But production has plummeted and now accounts for less than 10% of the world market share.
Mussa remembers a time when his clove trees alone were enough to support his family.
He, like many farmers on the island, blames the government's refusal to lift price controls and meet competition from Madagascar, Indonesia and other free-market producers.
"We're forced to accept the changes, but if the government price is acceptable -- if it is higher -- we'll all start planting more cloves again," Mussa said.
Rashid Ali Saleed from Zanzibar's Ministry of Trade, Industry and Marketing says the price set by the government -- clove farmers' sole buyer in Zanzibar -- is sometimes less than half the price cloves can fetch on the black market.
But Saleed says it is international competition that is currently hurting Zanzibar's spice farmers.
"The clove industry is very tricky. It's not like rice that you can buy and then sell it," Saleed said.
Cloves can only be exported, he says, which means the industry is reliant on the international market.
"We need to do research to see how private people can come in and rectify the industry," he said.
The uncertainty about the spice industry is causing Mussa's son Harib to have second thoughts about pursuing a career in farming.
"If I'm not making a profit, why would I want to be a farmer?" Harib said.
So he and his brothers, like many teenagers in Zanzibar, spend their days cashing in on a thriving tourist industry.
The government says tourism now accounts for just under 45% of the country's gross domestic product, bringing in around $42 million every year.
"I prefer to be a tour guide," Harib said. "Farming cloves is a long process by the time you plant, harvest and sell to the government. We're looking for an easier way to make money."
So-called "spice tours" have spread through the island's once thriving spice farms, including Mussa's.
He would prefer that his sons farm alongside him, but he also realizes that with 10 children to support, his son's daily spice tours provide much-needed income.
The challenge, say Zanzibarians, is now to profit from tourism while preserving a way of life on an island still very much defined by the spice trade.
Saleed hopes that branding Zanzibar's cloves -- similar to the way France brands its champagne -- might help the industry survive.
"You can't compare Zanzibar cloves to cloves from other parts of the world. We advertise Zanzibar as Spice Island, so we have to depend on cloves," Saleed said.