A dolphin hauled dead from a shark net off Noosa National Park last week has reignited interest in the Shark Control Program and the push to reduce the accidental catch of non-target species. The dolphin, found last week, was one of 13 inadvertently caught off the Sunshine Coast this year.

The system of 78 drum lines and 11 nets stretching from Bribie Island to Noosa also captured 84 sharks in 2006, including a four-metre tiger off Point Cartwright and a 3.4-metre hammerhead at Noosa. Three turtles and one whale were ensnared but released alive.

The bycatch is a sore point for conservationists, who argue that the toll on non-target species is too high for the program, which was introduced to Queensland in 1962 after fatal maulings at Noosa and Mackay in 1961. There have been no fatalities off protected Queensland beaches since.

During the first 15 years of the program, 468 dugongs, 2654 turtles, 317 dolphins and 10,889 rays were caught. Numbers have dropped steadily since new initiatives were introduced in 1992.

Shark control program manager Baden Lane said ongoing experimentation with different types of nets, hooks, baits and underwater acoustic devices had caused a constant decline in marine mammal catches and an increase in the number of animals released alive. This year's toll represented a significant drop from the 2005 total of 19 dolphins and nine turtles.

"We've come a long way and had some successes," Mr Lane said."We've been using a mesh over the drum-line bait, which deters dolphins and turtles but increases the chances of shark catch because it keeps the bait on longer.

"We're still trialling an artificial bait of compressed tuna, which hangs on the hook longer and is not attractive to dolphins and turtles. And we've developed a hook that has reduced the chance of turtle predation."

The department considered and rejected a proposal to use electro-magnetic shark-deterrent devices.

"There's no hard evidence to support it working, only anecdotal claims, and we can't afford the luxury of putting human life at risk in a trial," Mr Lane said.

Plans to trial a barium-impregnated shark net, which can be detected more readily by dolphins, have been put on hold because the commercial fishing mesh available is too small.

Mr Lane credited the introduction of underwater acoustic devices which emit a repellent, sonar signal as having had the greatest impact on whales and dolphins.

"In the early 1990s there were around 1000 humpback whales migrating north. "Now there's more than 7000 and since the introduction of the underwater pingers about 10 years ago we're not getting anywhere near the same number of collisions, despite the increasing numbers.

"We also have the marine animal release team, which went into action when a whale got caught at Coolum last month. That's something we never had in the old days."

Source: Sunshine Coast Daily