Sirenians typically inhabit warm, shallow, coastal waters, or rivers. Water flows between groundwaters and surface waters. It will also provide information on pollution in lakes and coastal waters. The thermocline may be present in shallower coastal waters. They appear in most of the inland waters of the United States. This includes many shallow coastal waters and reefs, but also some major shipping lanes. They inhabit the northern marine waters of Australia. This keeps the warm surface waters floating above the cooler deeper waters. Gerridae generally inhabit surfaces of calm waters. This is attributed to the differences in friction between land masses and offshore waters. Magnet fishing is subject to local regulations concerning outdoor waters. They always required assistance from tugboats in shallow waters. Cyanobacteria grew in relative abundance in these mineral rich waters. The species sometimes forms aggregations of thousands along slicks in surface waters. Finney tested the canoe in a series of sailing and paddling experiments in Hawaiian waters.