Imports of shark fin products into Hong Kong fell sharply in 2013, down nearly 35 percent, and re-export of shark fin materials fell 17.5 percent, according to the World Wildlife Fund.

Citing data from Hong Kong's Census and Statistics Department, WWF-Hong Kong reported the volume of imported shark fin products fell from from 8,285 metric tons to 5,412 metric tons last year.

The volume of shark fin re-exports fell from 2,428 metric tons to 2,003 metric tons.

Mainland China has traditionally been the largest re-export market for shark fins, but demand there appears to have declined significantly. Vietnam is now the largest re-export market, the WWF reported.

However, there is no apparent explanation why Vietnam has surpassed China in the re-export market; Vietnam does not have a culture of consuming shark fins, according to the South China Morning Post, which noted that in 2012, re-exports of shark fin products from Hong Kong to China fell by 90 percent.

Shark fins, most well-known as the staple ingredient in shark fin soup, are seen by some as a status symbol, the high price of shark fin soup a way to show off wealth, especially at events such as weddings.

But the popularity of the dish seems to be declining, perhaps in part to campaigns by environmental groups and government austerity measures.

"Shark-free banquets have become more popular over the past two years," Hong Kong wedding planner Tim Lau told WWF-Hong Kong. "At least 20 percent more wedding couples now choose shark-free banquets. Some of them even do so because their parents came up with the idea."

However, the WWF noted that the current system in place does not allow for the tracking of which species of sharks are being transferred through Hong Kong's ports.

"To better regulate the shark fin trade and improve its transparency, WWF calls on the Hong Kong government to begin collecting and releasing full statistics on the shark fin trade, including the species, volumes and countries of origin," said Tracy Tsang, WWF-Hong Kong's senior program director.

"The government should improve the existing codes, following the coding practice used for bluefin tuna, to allow for the identification of shark species that need to be tracked," Tsang said, according to the South China Morning Post. "Scientific identification, through DNA testing of randomly sampled shark fins, could also be deployed for verification purposes."

Currently trade in eight shark species is now restricted under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

A recent ratification in CITES rules has made room for more shark species to be given CITES protection.

The CITES decisions "to include more shark species in its Appendix II has been ratified, and the Hong Kong government should now be preparing to follow the updated CITES requirements,
the WWF said.