Off Coron Island . Depth > 40m. This freshwater lake is surrounded by limestone cliffs and served by a hot spring. The water temperature ranges from 27-40 0C. The transition between the layers of cold water and hot water is abrupt. The interface is sometimes visible. There are numerous shells on the bottom, shrimps on the walls and some rabbitfish in the shallow area. The above-water environment is equally fascinating. On Barracuda Lake imagine a bowl of broth (the lake) sitting in a large pot (the ocean). The bowl of broth is rainwater for the first four meters. In rainy season (now) this fresh water is cool (26 to 28 degrees). In dry season this fresh water warms up from the hot salt water below it. The first layer of hot salt water starts at 4 meters and goes down to 13 meters. Its' temperature is about 33 degrees. The second layer is at 38 degrees. YOU HEAT UP ON THIS DIVE INSTEAD OF GETTING CHILLED. You can actually see fingers of REALLY HOT water coming out of cracks in the rock just like the swirls off of the bottom of a pot before it boils. The bowl (ring of mountains) that holds the broth has a V shaped crack down to within four meters above sea level at the place where we climb over the lip of the bowl. When you climb into the lake you go to the left side and swim in away from the ocean before you descend to the mouth of the cave. The cave heads back towards the ocean and the current in the cave changes direction with the tide.
