Researchers from the Tropical Rivers and Coastal Knowledge (TRACK) program have concluded the big rains pushed the prawns from their estuary nursery grounds out into the sea as the salinity levels dropped.

Researchers fought their way through crocodiles, extreme heat and biting insects to collect prawn samples in the Gulf of Carpentaria during the wet season.

TRACK researcher Assoc. Professor Michele Burford said the flooding had negative impacts on some primary industries, but meant the banana prawn fishery had a big year.

“Last summer we had a one in 50 year flood, which is at the extreme end of spectrum for understanding how river flows affect prawns,” he said.

“If you start taking water out of rivers flowing into the Gulf there will be less flooding and as a result, less prawns available for fishers to harvest.”

Researchers are now trying to find out how much the natural flooding of estuaries varies from year to year, and what this means for prawn production.

“We don’t understand enough about the relationship between estuaries and freshwater flows,” Assoc. Professor Burford said.

“But we do know that water running out to sea is not wasted.”

She said if the northern rivers were dammed or had water taken out for irrigation, less fresh water would reach the estuaries and fishers wanted to know what this would do to their livelihoods.

Raptis and sons fishing company manager Michael O’Brien said the research was very valuable.

“We want a good knowledge database on how water flows affect banana prawns,” he said.

“The northern prawn industry is recognised for its sustainable practice. We’ve spent a lot of money and gone through hardship to get it that way. Where we used to run 300 fishing boats, now we run only 50. It’s not just about economic yield anymore—it’s about maximum sustainability.”