From The Human Clans
The people of Shark Clan are warriors and sailors that dwell in the seas of the Qi Province. They are also rogues -- pirates, that make their living by attacking other ships and stealing their goods. Little is known of Shark Clan, for historians are not exactly welcome among them. All I can say is that if you sail upon the Reshal Sea and are approached by a ship with a shark's flag, you would do well to pray to Lemicus for safety.
Shark Clan is widely conflated with the Red Sash Pirates (who are also known as just 'the Red Sash') by outsiders, but this is not really correct. While some Shark Clan members do join in with the activities of the Red Sash Priates, the Red Sash is an entirely distinct group from the Clan. 
- GM Jaedren on the forums, 7/6/2011, and GM Persida on the forums, 4/13/18