Frequently seen in the waters around Sipadan: green and hawksbill turtles (which mate and nest there), enormous schools of barracuda in tornado-like formations as well as large schools of big-eye trevally, and bumphead parrotfish. Pelagic species such as manta rays, eagle rays, scalloped hammerhead sharks and whale sharks also visit Sipadan. A turtle tomb lies underneath the column of the island, formed by an underwater limestone cave with a labyrinth of tunnels and chambers that contain many skeletal remains of turtles that become lost and drown before finding the surface. Visiting Sipadan Island requires a permit issued by Sabah Parks, a Sabah Government agency. Since 2019, there are 178 permits available each day. Sipadan Island will be closed from 1 November until 30 November 2020 for 'Marine Life Recuperation'. It will open again to tourism operations from 1 December 2020.