The Penghu Islands are located in the Taiwan Straits. The China coastal current, a branch of the Japan current, and the South China Sea monsoon current come together in the surrounding seas, bringing Penghu rich and varied marine ecological resources.
There is a large difference in depth between the inner bays and surrounding seas of Penghu. The inner bays are generally no more than 15 meters deep, although at a maximum they can reach 25 meters, while the surrounding seas are much deeper. This means that coastal slopes are gentle, and the intertidal zones are quite wide.
Sea turtles of numerous kinds are found in the waters of Penghu. The island of Wangan is where green sea turtles come ashore to lay eggs more regularly than at another place in the Taiwan area, and the beach where they come ashore has been designated as a green sea turtle nesting preserve. The Penghu National Scenic Area Administration has established a Green Sea Turtle Conservation Center on Wangan to provide information on the marine ecology.
Penghu has a cornucopia of fishery resources; according to a survey carried out by the Penghu branch of the fisheries institute, there are a total of 723 species of reef fish, bottom fish, and migratory fish. The rockfish grouper has been named the Penghu county fish.
The waters around the Penghu Islands provide fine conditions for the growth of coral, which covers large areas of the ocean floor here and provides habitat for a wealth of ecological resources. Soft and hard coral in an endless variety of shapes and colors abound, providing astonishing underwater landscapes. In the outer seas there is also an abundance of seaweed—more than 40 species—of which some, including laver, have economic value as a food.
In the large intertidal zones around the Penghu Islands you can find a variety of sea snails, clams, and other seashells, as well as crabs, lobsters, hermit crabs, and other arthropods. These islands also have the largest number of ancient stone fish traps in the Taiwan area. Today, these traps offer fun in the form of recreational fishing in the itnertidal zones.
The large and vastly varied ecological systems in the intertidal zones of the Penghu Islands have always been an important part of the livelihoods of the island people. In the future they will serve as a stage for experiencing the marine ecology.