• Four shark attacks reported in New South Wales in just 48 hours.
• Sydney's northern beaches closed after critical injuries to surfers.
• Heavy rainfall has worsened visibility and water quality, attracting sharks.
• Experts warn of increased shark activity in the area.

Beaches in Sydney remain closed after a series of shark attacks, with the latest incident involving a surfer on the Mid North Coast who sustained minor injuries. This marked the fourth shark attack in New South Wales within 48 hours, heightening concerns among local authorities and beachgoers, as heavy rains have contributed to murky waters where sharks thrive, according to channelnewsasia and Reuters.

A surfer in his twenties was critically injured on Monday after being bitten by a shark at Manly Beach, while a 12-year-old boy was also severely injured at a Sydney Harbour beach the same day. The previous day, another young boy narrowly escaped an attack where a shark bit his surfboard, exemplifying the increase in shark interactions due to favorable feeding conditions created by recent weather changes, as detailed in reports by BBC and Reuters.

Authorities are urging people to stay out of the waters, as the presence of bull sharks is thought to be heightened after heavy rainfall and runoff from rivers, which attract the species for feeding. Experts emphasize the importance of heeding public safety advisories, given that bull sharks are considered potentially dangerous to humans, according to BBC and channelnewsasia.