A new study has found that nearly half the coral trout caught on the Great Barrier Reef come from marine reserves – where protected fish grow larger and produce far more offspring.
The research was led by Professor Michael Bode from QUT, co-authored by JCU TropWATER researchers Dr Maya Srinivasan and Dr Severine Choukroun and JCU’s Professor Geoffrey Jones.
Dr Srinivasan said the Great Barrier Reef is protected by a network of marine reserves designed to conserve its biodiversity.
“These reserves protect critical habitats for many species, including the coral grouper – also known as the coral trout - the reef's most valuable commercial fish.
“Marine reserves make up less than a third of the reef area, but they account for 55% of coral trout reproduction and 47% of the catch,” said Dr Srinivasan.
Professor Bode said the marine reserve network on the Great Barrier Reef is not just a tool for conservation, it’s a vital contributor to the sustainability of local fisheries and local jobs.
“By protecting fish populations within these no-take zones, we not only safeguard biodiversity but also guarantee that there will be a new generation of fish on the reefs that are open to fishing.
“This is a clear example of how protected areas can also benefit local communities and the economy, as well as the reef’s unique biodiversity,” said Professor Bode.
The study was conducted by a team including researchers from James Cook University and the Australian Institute of Marine Science.
It combined decades of fish surveys, genetic parentage analysis of coral trout populations, advanced oceanographic models, and high-resolution reef mapping to estimate coral trout reproductive output in the protected areas and their contribution to areas open to fishing.
Dr Srinivasan contributed to the collection of genetic parentage data, while Dr Choukroun developed the statistical model for coral trout biomass.
“Importantly, the findings show that despite marine reserves reducing the area available for commercial fishing, the network has a positive, amplifying effect on fishery yields.
“On many reefs, the density of fish in reserves is two to three times higher than on fished reefs, resulting in a higher reproductive output and a more sustainable fishery,” said Dr Srinivasan.
She said the study also highlights how all the reefs in the system benefit from the marine reserves, through higher larval supply.
“Across the Great Barrier Reef nearly 95 per cent of reefs receive at least 30 per cent of their larvae from reserves, and 93 per cent of fished reefs benefit from at least 30 per cent of their catch originating from protected areas,” said Dr Srinivasan.
Professor Bode said the study reinforces the idea that well-managed marine reserves can be a win-win for both conservation and the fishing industry.
“The results provide clear guidance for future marine management efforts, showing that these reserves contribute significantly to sustainable fishery yields, as well as to the resilience of coral reef ecosystems,” said Professor Bode.
The full study is available in Science Advances here.
