Fishers' memories reveal long lost-lost trends. Credit: University of Queensland

A new scientific study is reconstructing long-term data on fish catches using fishers' memories to reveal how their rewards have declined over the past 50 years.

Dr Ruth Thurstan, who conducted the research with the ARC Centre of Excellence for Coral Reef Studies at The University of Queensland said more than 100 fishers from the commercial and recreational fishing sectors were asked to recall what they remembered about fishing on the Great Barrier Reef, Australia.

"The historic data revealed that catch rates (the number of coral trout caught per fisher per hour) have declined since the 1970s, despite rapid advances in fish finding technology we use today," Dr Thurstan said.

"In the past, recreational fishers have blamed the commercial live reef fish trade for dwindling stocks, while commercial fishers claim expanding no-take zones on the Great Barrier Reef in 2004 is behind the problem.

"However, we found catch rates actually began falling way before either of those factors were introduced."

The scientists travelled 1400 kilometres along the coastline interviewing fishers about the type of gear they used in the past, the number of fish caught, and how far offshore people fished.

Historical information was translated into data to map long-term fishery trends dating from the 1950s to now.

The commercial fishery trade began in Australia after WWII but no official records of individual catches were kept until the late 1980s.

"We found that some people were able to recall their earliest memories of fishing on the Great Barrier Reef, up to 60 years ago," Dr Thurstan said.

"The oldest person we spoke to was 92 years-old. He had fished around Green Island, near Cairns, his entire life.

"Not only was he able to tell us about catch rates but he also provided valuable information about how the wider environment had changed as the region became more populated."

Professor John Pandolfi, a research team member from the ARC Centre of Excellence for Coral Reef Studies at UQ said that clearly, fishing rewards had changed through time.

"Fishers have a huge contribution to make – they understand the value of knowing where we've come from to help manage trout fisheries for the future," Professor Pandolfi said.

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