Fishing is the activity of hunting for fish by hooking, trapping, or gathering animals not classifiable as insects which breathe in water or pass their lives in water. By extension, the term fishing is applied to pursuing other aquatic animals such as various types of shellfish, squid, octopus, turtles, frogs, and some edible marine invertebrates. The term fishing is not usually applied to pursuing aquatic mammals such as whales, where the term "whaling" is more appropriate. Fishing is an ancient and worldwide practice with various techniques and traditions and it has been transformed by modern technological developments. In addition to providing food through harvesting fish, modern fishing is both a recreational and professional sport.