In the past, the whale shark has been of little interest to fisheries. Now, commercial fishing for whale sharks are limited, but may expand from an increased demand for food products. In Taiwan around 100 whale sharks are caught annually. The meat of the whale shark is sold for high prices in this country, and since of this, there have been larger harvests of whale sharks over the last few years. Fishing for this shark also occurs in the Philippines, particularly in the Visayas and Mindanao areas, providing food for the local fishing communities. Whale shark fins are sold in the Orient, especially in Hong Kong. Occasionally, whale sharks are captured accidentally along the coast of India. Sometimes the flesh is eaten and the liver oil is used for waterproofing wooden fishing boats and for the manufacture of shoe polish, and it is also used as a treatment for some skin diseases. The fins of Whale sharks are also sold in India. Often, the whale shark is used as an indicator of waters which are rich in plankton-feeding fish that will, in turn, attract more valuable species, such as tuna. Whale sharks have been kept in aquaria in Japan, but their large size and their diet has made it hard to keep a whale shark in an aquarium. Some locations where the presence of whale sharks appears to be predictable, are increasingly targeted by commercial tourist operations.