Where did Ge Hong find the hippocampus?

Coastal areas of Guangdong and Fujian. Ge Hong was a famous Taoist theorist, alchemist and physician in the Eastern Jin Dynasty. In the book Bao Puzi, it can be known that Ge Hong discovered hippocampus in some parts of Guangdong, Fujian and other modern coastal areas. By April 26th, 2023, it had been used as medicine for more than 2,000 years. Hippocampus is a dry body of linear hippocampus, spiny hippocampus, large hippocampus, three-beaked hippocampus or small hippocampus (sea maggots) of the family Syngnathidae. Hippocampus is a warm medicine with sweet and salty taste.