Desalination discharge a boon to fish along the coast of Australia

Brooks Hays
Scientists in Australia found fish are attracted to the salty discharge from a desalination plant outlet. Photo by McLennans Diving Service
Scientists in Australia found fish are attracted to the salty discharge from a desalination plant outlet. Photo by McLennans Diving Service

Dec. 18 (UPI) -- The salty discharge spit back into the ocean by a large desalination plant in Sydney, Australia, is attracting fish to its shores, according to new research.

Scientists at Southern Cross University observed a three-fold increase in fish numbers near the Sydney Desalination Plant's discharge outlet.


"There was a 279 percent increase in fish life," researcher Brendan Kelaher, a professor or marine sciences at Southern Cross, said in a news release. "It is an important result, as large-scale desalination is becoming an essential component of future-proofing the water supplies of major cities, such as Sydney, Perth, and Melbourne."

As the planet warms and weather becomes more extreme, with droughts getting longer and more intense, water resources in many parts of the world are becoming scarce and vulnerable to exploitation. To cope, some places are turning to desalination, the conversion of saltwater to freshwater.

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

Though new desalination plants continue to be constructed, few studies have closely examined the effects of plant discharge on marine life. Kelaher and his colleagues tracked biodiversity near the Sydney plant's discharge for seven years, including a period when the plant ceased operations.


The research team reported their results Wednesday in the journal Environmental Science and Technology.

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"At the start of this project, we thought the hypersaline brine would negatively impact fish life. 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. "Importantly, the positive effects on fish life also included a 133 percent increase in fish targeted by commercial and recreational fishers."

Researchers estimate the fish are attracted to the turbulence created by the mixing of extra-salty water with regular ocean saltwater, but more research is needed to determine if there are other factors at play.

While researchers agree that desalination plants should continue to be built in ways to minimize environmental impacts, the authors of the new study suggest discharge outlets could be used to enhance marine habitat.

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