Shark patrols have been stepped up along Illawarra and South Coast beaches as warmer waters bring schools of fish near the shore - followed by bigger predators seeking to make a meal of them.Patrollers say they have spotted sharks as close as 500m from the shore, including hammerheads, tiger sharks and even some great whites in recent months.But at the scene of the region’s last shark attack, Lake Illawarra, a vandal has cut a 2m hole in the shark net set up to protect swimmers.A significant knife and effort would have been needed to cut through the net, understood to contain stainless steel and copper wire. Efforts are underway to fix the net but the concern is for how long the lake has been unprotected.In January 2009, Windang man Steve Fogarty was attacked by a dusky whaler shark while snorkelling near the Windang boat ramp. In 2010, a great white shark was spotted in the lake in April and a 1.8m seal in June.Lifesavers were yesterday warning NSW swimmers to take care after a man was bitten on the arm by a shark during an 8pm surf session on Tuesday at a beach on the Central Coast.Several large sharks were spotted yesterday off the Central Coast, prompting warnings to avoid swimming solo in the evening and early morning.Yesterday Harry Mitchell from the Bendigo Bank Aerial Patrol, which flies over Illawarra and South Coast beaches, said there had been plenty of sightings as the patrols were stepped up from weekends to every day of the week.‘‘No area is immune - sharks will go where they can get a feed,’’ he said.‘‘White pointer sharks love the cold water [but] when the water temperature’s right, the warm waters do attract other species of sharks.’’‘The red and yellow aerial patrol planes are fitted with sirens in case a shark is spotted near a populated beach. They have been looking out for sharks as well as for the schools of fish that attract them.Mr Mitchell said numerous sharks had been spotted in the areas around Sussex Inlet, Mollymook, Jervis Bay, Windang-Port Kembla, Lake Conjola, and Towradgi-Corrimal.Wollongong City Council recreation services manager Mark Bond said no Wollongong beaches had been closed because of sharks this summer.