This topic reminds me of an AD shooted by Yaoming many years ago. In that AD, some rich people were sitting around a table and enjoying the shark fins. All of them were satisfied with the food until the curtain opened and showed that there were just at a restaurant under the water. Outside the window, there was a poor shark without its fins. Then all the people began to throw up. The theam of the AD is: no trade no killing. In modern society, people have enough food for living, especially for the rich people, they try to seach for some rare food which only they can enjoy.The food they eat may not be really healthy for their body, but can prove their their social status. Under such a background, new trade happened. even most of the trades are forbiddened and illegal. In order to get more benefits, someone kill the rare species. So, how the sharks survival without their fins? How goverments prevent the trades?