Shaddock, also known as force fish or rib fish, belongs to the herring family. Every year after the Qingming Festival, the fish enters the Huangda Ocean, the outer ocean of Qu Harbor, and the area around the Mazu Ocean in Zhoushan to spawn. Due to the fast swimming speed of the herring, fishermen say it is "a small herring with no belly, swimming through seven valves of the ocean overnight", so it is difficult to grasp its laws, coupled with the group is small, the annual catch is only about 2,000 tons.

The herring meat white quality fresh, taste like anchovies, in addition to fresh food, can also be salted and processed into herring replica bags, including three times the salt processing of the three abalone herring for the best, is Daishan's famous seafood. The herring has the medical function of nourishing the heart and calming the mind, strengthening the spleen and benefiting the stomach. The flesh of the herring can cure chronic diarrhea and its scales can cure warts.