Overfishing can devastate it and once gone the undersea habitat becomes much poorer. • 5 different kinds of kelp should be present in the Forth. • They grow fast, to between 2 and 3 meters tall and can make amazing underwater forests. • They anchor themselves onto rocks on the seafloor with claw like ‘holdfasts’ • Kelp is rich in iodine, is used in medicine, beer, ice cream and cosmetics. • Sheep eat it and it makes wonderful fertiliser.