FIFTEEN sharks have been caught off the Bundaberg coast so far this year - and six of them were more than 2m long, according to figures released by Maritime Safety Queensland.
But while other regional waters have noticed an increase in shark numbers, Bundaberg has seen fluctuations in activity in the past two years.
For the same period last year 23 sharks were caught, with 10 of those more than 2m long, while in the first three months of 2010, 16 sharks were caught, with eight of them over 2m.
The state's shark control program has 20 drumlines set up to 400m offshore at Bargara, Kelly's Beach, Nielson Park and Oaks Beach to protect swimmers.
A spokesperson for Maritime Safety Queensland said the drumlines worked by catching actively feeding sharks using a shark hook suspended from a large plastic float anchored to the sea bed.
"The equipment is serviced every second day, weather permitting," the spokesperson said.
"The species caught since January include eight tiger sharks, two long nose whalers, one bull whaler, three pigeye whalers, and one tawny shark - which was released as it is non-dangerous."
But the Maritime Safety Queensland data does not reflect shark activity in the Burnett River, which can provide the perfect breeding ground for bull sharks.
Shark research scientist Jonathan Werry said bull sharks used rivers and estuaries as a nursery for their young.
"The bull sharks are unique in that their juveniles are born in the rivers and grow up there before going offshore," Dr Werry said.
While bull sharks have long been considered very site-attached, compared to other large range sharks that travel further afield, new tracking information suggests the aggressive species will also travel great distances in search of food.
Recent data from a 2.2m bull shark tagged in Moreton Bay in 2009 showed it travelled north as far as about 1000km past Bundaberg last year, before returning to southern waters.