The desalination plant in Sydney is one of the largest in the world, and in times of reduced rainfall, it supplies roughly 15 percent of the Sydney's drinking water.

Now, a seven-year study by Southern Cross University (SCU) and the University of New South Wales has shown that in the areas where the plant discharges it's excess salt -- roughly 300 metres offshore -- fish numbers have exploded by 279 percent.

"At the start of this project, we thought the hypersaline brine would negatively impact fish life," lead researcher, Professor Brendan Kelaher from SCU said.

"We were both surprised and impressed at the clear positive effect on the abundance of fish, as well as the numbers of fish species."

Kelaher said that the increase is good news for fishermen as well as the environment, with a 133 percent increase in species targeted by commercial operations and recreational anglers.

The research is important because in the future, desalination plants could play a large role in water security, not just in Australia but around the world.

"With growing populations and climate uncertainty, water security has become a global concern. Desalination is one way to help shore up water supplies in many parts of the world," Kelaher said.

The plant uses osmosis to convert salty seawater into safe and clean drinking water, a process which results in a massive amount of hypersaline brine.

Initially the researchers believed that the hyper-salty water emitted by the plant would reduce fish numbers -- the reason why it has had the opposite effect is unclear.

"We think they might be responding to turbulence created by dynamic mixing associated with the high-pressure release of the brine. However, more research is needed," Kelaher said.