From the perspective of ecology and health, the best quality of sea cucumbers in these places should be those in Weihai and Long Island. The reason is very simple. Dalian belongs to Bohai Bay, which is relatively polluted, and the fluidity of seawater is relatively poor. Weihai belongs to the Yellow Sea, and the water quality should be better. As for Long Island, I don't know whether it belongs to the Yellow Sea or the Bohai Sea (Long Island faces Penglai across the sea, and the dividing line between the Yellow Sea and Bohai Sea is in Penglai). However, I have traveled to Long Island once. Long Island City (formerly called Long Island County) has excellent natural environment, and there is basically no industry on the island. It relies entirely on mariculture and tourism as its economic pillar. The whole Long Island City doesn't even have a bus (it happened several years ago, but now I don't know what happened). The seawater quality is very good, and there is almost no direct pollution. Presumably, the seafood produced here is healthier, and finally it is Qingdao. The pollution around Qingdao's coast is still quite serious. If you enter Qingdao by train. The above is only a personal one-sided analysis of the ecological environment, hoping to help the landlord!