Danny Bucher, Senior Lecturer at Southern Cross University.
Danny Bucher, Senior Lecturer at Southern Cross University. Contributed

Predator was after baitfish says shark expert

WARMER waters and the ready availability of baitfish could explain any increase in shark activity across Northern Rivers beaches according to marine ecologist Daniel Bucher.

Sharks are "a combination of predator and scavenger" and have a simple life quest to "follow the food," Dr Bucher said from the Marine Ecology Research Centre at SCU.

Factors that could be contributing to extra shark activity include the availability of more food in an area, he said. "Baitfish will attract predator fish including sharks," he said.

Increased activity can also coincide with warmer summer ocean currents because they speed up the metabolism, and therefore the appetite, of the cold-blooded sea creatures, he said.

"Also, of course, you get more humans enjoying the water when it is warm," he said.

Sharks can also be lured closer to shore after rainfall as they are attracted to river mouths and other outfalls to see what washes out, he said.Without specific details about the attacks, including details about the wounds, it was very hard determine if the same shark could have been involved in yesterday's fatal at Ballina, and Sunday's wounding at Seven Mile beach, he said.

"More than likely it was two different sharks operating under two different sets of circumstances," he said.

"Very few attacks are linked to the same animal. Most likely they are isolated and unconnected events," he said.

Dr Bucher's advice for avoiding sharks is:

  • Never swim after rain, especially near river mouths or stormwater drains
  • Don't swim if you know there are plenty of baitfish around.
  • Dawn and dusk are notorious for shark activity
  • Patrolled beaches mean there are plenty of eyes on the look out.
  • The safest beach is where a shark has been spotted an you don't go in