In the Philippines, over thirty species of whales and dolphins can be observed around Pamilacan in Central Visayas, Davao Gulf, the northern coast of the province-island Babuyan Islands in Batanes, Pasaleng Bay, and Malampaya Sound, Palawan. The Visayas is particularly known area for dolphin sightings, and is home to one of the larger populations of the Fraser's dolphin in the world. Dolphin species in the Visayas are attracted to fish lures and to commercial fishing operations. In the northernmost province of Batanes, at least 12 species of whales and dolphins has been sighted, making it the single location in the country with the highest cetacean diversity. There seems to be no specific whale watching season in the Philippines, although the calmer waters of the summer season typically provides the best conditions. Some populations, like those of the Irrawaddy dolphin, Bryde's whale, and humpback whales in Batanes, appear migratory. Other populations have yet to be studied. Some former coastal whaling communities in the Philippines have also started to generate whale watching income.