Before the eruptions of Taal Volcano in the 18th century, Pansipit was a navigable channel connecting Taal Lake to Balayan Bay. Sailing ships and Chinese junks freely entered Taal Lake to visit the town of Taal and other population centers along its shores. The water of the lake was then saline. In 1754, after the culmination of worst eruption of Taal Volcano had subsided, the mouth of the river was found blocked by volcanic material, eventually raising the level of the lake. A narrower Pansipit River eventually formed from the layer of ejecta from the volcano and a new course was created. The present source of the river on the lake is perhaps north of the old entrance with the new channel joining the old channel about down the river valley. The change in the elevation of the lake also prevented sea water from flowing into the lake thus turning it to freshwater, its marine life evolved and adapted to freshwater living.