Taal Lake, formerly known as Bombón Lake, is a freshwater lake in the province of Batangas, on the island of Luzon in the Philippines. The lake fills Taal Caldera, a large volcanic caldera formed by very large eruptions between 500,000 and 100,000 years ago. It is the country's third largest lake after Laguna de Bay and Lake Lanao. Volcano Island, the location of Taal Volcano's historical eruptions and responsible for the lake's sulfuric content, lies near the center of the lake. There is a crater lake on Volcano Island. Known as the Yellow Lake or the Main Crater Lake, it contains its own small island, Vulcan Point. Vulcan Point was thought to be the largest third order island in the world but Treasure Island (Ontario) is much bigger and is thought to be the world largest, and is also on a freshwater lake.
The Taal Lake basin was first declared as a national park, the Taal Volcano National Park, by Proclamation No. 235 on July 22, 1967 covering 62,292 hectares (153,930 acres).
Under Republic Act 7586, otherwise known as the National Integrated Protected Areas System (NIPAS) Act of 1992, the area was reestablished as the Taal Volcano Protected Landscape by Proc. 906 on October 16, 1996. The protected area is managed by a Protected Area Management Board (PAMB) and has a Chief Operating Officer called a Protected Area Superintendent. A Management Plan was crafted and approved by the PAMB in 2009 and now serves as the blueprint for lake conservation.
Taal Lake was once just an arm of Balayan Bay. A series of major eruptions in the early 18th century battered the lakeside towns with earthquakes and volcanic debris. The activity culminated in 1754 with Taal Volcano's largest eruption that blocked Pansipit River with tephra, eventually submerging some of the towns by the rising lake waters, as the lake's sole outlet to the sea was blocked. (Remnants of the old lakeside towns are reported can be seen under the lake's waters). The poblaciones (town centers) of Lipa, Taal, Sala, Bauan and Tanauan, formerly located along Taal Lake, were moved away and reestablished several kilometers away from its shore after the activity had subsided.
Since the 1754 eruption, the surface elevation had gone up from sea level (as the lake was freely navigable from Balayan Bay) to 5 metres (16 ft) above sea level. Several centuries of precipitation have diluted the lake's once saline waters into freshwater.
Over a century after the big eruption, newer towns along the lake were again established, carved from the larger towns - Talisay (established 1869, from Taal), Cuenca (1877, from San Jose), Alitagtag (1910, from Bauan), Mataasnakahoy (1932, from Lipa), Agoncillo (1949, from Lemery), San Nicolas (1955, at the former location of Taal town), Laurel (1961, from Talisay), Santa Teresita (1961, from Taal, San Luis and San Nicolas) and Balete (1969, from Lipa).
Because the lake was previously connected to the sea, it is home to many endemic species that have evolved and adapted to the desalination of the lake's waters. The lake has a freshwater-adapted population of trevally, Caranx ignobilis. This fish, also found in Pansipit River, is locally called maliputo. Its most popular endemic species is the overharvested Sardinella tawilis, a freshwater sardine. The two other endemic fish species in Taal Lake are the gobies Gnatholepis volcanus and Rhinogobius flavoventris.
Taal Lake is also home to one of the world's rarest sea snakes, Hydrophis semperi. This particular species is only one of two "true" sea snake species that are known to live entirely in freshwater(the other is Laticauda crockeri from the Solomon Islands). Bull sharks, Carcharhinus leucas, used to be part of the lake's once-diverse ecosystem but were extirpated by the locals by the 1930s.
Jaguar guapote (Parachromis managuensis), a predatory piscivore, a carnivorous fish that primarily eats other fishes, was found illegally introduced into the lake. The alien fish could proliferate in all areas of lake because of the abundant aquatic vegetation which they use for spawning and feeding, plenty of natural food, and favorable warm environment. Its presence could seriously affect the native fish population.
On January 5, 2008, the Bureau of Fisheries and Aquatic Resources announced that a fish kill at Taal Lake (January 2 to 4) caused the 50 metric tons or ₱ 3.25-million ($79,268) loss of cultured tilapia in the villages of Leviste and Balakilong in Laurel and in Barangay Aya and Barangay Quiling in Talisay. 6,000 maliputo fishes ($5,609) also died at Quiling. Toxic sulfur and high level of hydrogen sulfide in Ambulong while low dissolved oxygen caused the deaths.
On May 30, 2011, the Bureau of Fisheries and Aquatic Resources announced a fish kill of 750 metric tons. According to the scientists, the onset of the rainy season brought a sudden drop on the water temperature, which lowered the oxygen levels on the lake.
Regular tours of the lake are available to tourists. After crossing the lake, visitors travel to the top of Volcano Island on horseback. During their trip up and down the mountain, visitors are treated to a stunning view of the lake and its surroundings.
In mid-2007, controversy ensued when the Korean firm Jung Ang Interventure was given clearance to build a health spa on Volcano Island itself along the lake's edge. Over the course of the next few weeks, several government officials expressed their disapproval of the construction project.
On June 28, the DENR suspended the Korean firm's environmental clearance certificate, rendering them incapable of pursuing further construction on the island until they secure other necessary permits. Because of the unpopular public reaction to the project, the Korean company's permit was permanently revoked by the DENR in early July 2007.
In 2015, Taal Lake is an ideal and up and coming spot for kiteboarders, as it provides large space with few obstacles, also being close to Manila. It is the home of Taal Kiteboard Association.