Shark finning is banned in several countries, but the trade is flourishing in Hong Kong, where the fins are used in shark fin soup, a dish considered a prestigious delicacy, and in some types of traditional Chinese medicine. Hong Kong accounts for 50% of the global shark fin trade, according to the WWF courtesy Gary Stokes

Many restaurants and hotels in Hong Kong have chosen not to serve shark fin soup , and last year a Chinese State Council said they are planning to ban shark fin soup from being served at official banquets in China. courtesy Gary Stokes

Several thousand shark fins laid out to dry were found on the rooftop of a building housing seafood suppliers in Kennedy Town in central Hong Kong. Photographer Gary Stokes from the Sea Shepherd Conservation Society received a tip from an unnamed person earlier this year and took these pictures. courtesy Gary Stokes

Shark finning is heavily criticized because of the world's dwindling shark populations, and because some fishermen cut off the fins and then throw the rest of the shark back into the water, dead or alive. courtesy Gary Stokes

Shark fins used to be laid out to dry openly on ground level in Hong Kong, but finding another place to dry them -- out of sight of the public --might be a way for shark fin traders to avoid criticism. courtesy Gary Stokes

Workers lay out and turn the fins. Stokes told CNN that the workers were "shocked" when the photographers walked out onto the roof on January 1. courtesy Gary Stokes

"The big issue is that shark fins aren't illegal," Stokes said. According to the WWF, 181 shark and related species were listed as threatened with extinction in 2010. courtesy Gary Stokes