The Australian government has said it is making good progress in culling coral-eating starfish that have been blamed for munching through much of the Great Barrier Reef.

 

Greg Hunt, the environment minister, said 250,000 crown-of-thorns starfish had been killed by a new culling method over the past 21 months, a four-fold increase on the previous rate of removal.

 

The new method, developed by James Cook University, involves a single injection into the starfish; previously the multi-armed creatures needed to be injected about 20 times.

 

The injections, administered by divers, cause an allergic reaction in the starfish, killing it. Warren Entsch, MP for Leichhardt, said divers were now able to cull more than 1,000 crown-of-thorns starfish in a 40-minute dive.

 

Hunt said the new injection has “immediately improved the efficiency and effectiveness” of reducing crown-of-thorns starfish numbers. In December the government announced an additional $1.1m to combat the problem, which has been used for a new vessel for the starfish-killing divers.

 

Chemical runoff from agriculture has been blamed for a surge in numbers of the starfish, which are thought to feed on the nutrients from pollution.

 

Although they are always found on the reef, an explosion in their numbers can cause serious damage because they devour healthy coral.

 

The Australian Institute of Marine Science estimates the Great Barrier Reef has lost half its coral cover in the past 30 years; 42% is due to the crown-of-thorns starfish infestation.

 

Scientists say an outbreak can destroy between 40% and 90% of the corals on the reef.

 

Injections which kill the starfish are part of the government’s Reef 2050 plan to help improve the health of the Great Barrier Reef, which has come under severe stress from cyclones, coral bleaching and variable water quality.

 

Critics of the strategy claim that the injections are largely futile because some female crown-of-thorns starfish can produce up to 60m eggs.