Laguna de Bay (Spanish for "Lagoon/Lake of Bay"; , ), also known as Laguna Lake, is the largest lake in the Philippines. It is located southeast of Metro Manila, between the provinces of Laguna to the south and Rizal to the north. A freshwater lake, it has a surface area of 911–949 km² (352–366 sq mi), with an average depth of about and an elevation of about one meter above sea level. The lake is shaped like a crow's foot, with two peninsulas jutting out from the northern shore and filling the large volcanic Laguna Caldera. In the middle of the lake is the large island of Talim. The lake is one of the primary sources of freshwater fish in the country. Its water drains to Manila Bay via the Pasig River. Environmental issues such as water quality problems created by population pressure and industrialization, invasive species and overfishing are of concern for the lake, hurting its economic importance to the country. As population expands in the Bay, its expected to rely more heavily on the lake for freshwater supply, thus water quality directly affects human populations. Etymology Laguna de Bay means "Lagoon of [the town of] Bay" for the lakeshore town of Bay (pronounced Bä'ï), the former provincial capital of Laguna province. Alternate spellings of the town's name include "Bae" or "Ba-i", and in the early colonial times, "Bayi" or "Vahi". The town's name is believed to have come from the Tagalog word for "settlement" (bahayan), and is related to the words for "house" (bahay), "shore" (baybayin), and "boundary" (baybay), among others. The introduction of the English language during the American occupation of the Philippines, elicited confusion as the English word "bay", referring to another body of water, was mistakenly substituted to the town name that led to its mispronunciation. However, the word "Bay" in Laguna de Bay has always referred to the town. The Spanish word laguna refers to not just lagoons but also for freshwater lakes, aside from lago. This would make the lake's alternate name, "Laguna Lake", tautological. However, the "Laguna" in "Laguna Lake" refers to the province of Laguna, the province at the southern shore of the lake, and not the lake itself. The province, though, was in turn named after the lake and was originally called La Laguna until the early 20th century. In the pre-Hispanic era, the lake was known as "Puliran Kasumuran"