Lobsters are caught using baited one-way traps with a colour-coded marker buoy to mark cages. Lobster is fished in water between 2 and 900 metres (1 and 500 fathoms), although some lobsters live at 3,700 metres (2,000 fathoms). Cages are of plastic-coated galvanised steel or wood. A lobster fisher may tend as many as 2,000 traps. Around year 2000, owing to overfishing and high demand, lobster aquaculture expanded.  As of 2008, no lobster aquaculture operation had achieved commercial success, mainly because lobsters eat each other (cannibalism) and the growth of the species is slow.