Turtle recall

For 50 years, UQ Adjunct Associate Professor Col Limpus AO PSM has been the driving force behind the conservation of Australia's loggerhead turtle population.

Not bad for a man who admits he “wasn’t a big fan” of the shelled ocean dweller when he began his research career.

As a budding scientist in the 1960s, Limpus (Bachelor of Science ’62, Graduate Diploma of Education ’63, Master of Science ’76, Doctor of Philosophy ’85) was working as a high school teacher in North Queensland. During the summer months, he would visit Mon Repos – a globally significant nesting and hatching site for the endangered loggerhead turtle near Bundaberg – to photograph and observe the reptiles.

“I had grown up in the Bundaberg area and turtles were just another part of the living on the coast. At the time, I was more interested in sea snakes,” Limpus said.

“I met a visiting zoologist at Mon Repos in 1968 who was involved with turtle studies. He identified a conservation problem with flatback turtles and persuaded me to do a study. Loggerhead turtles were on the beach as well, so we began tagging them.

Five decades on, Limpus is the Chief Scientist at the Aquatic Species Program at Queensland's Department of Environment and Science and is one of Australia's leading minds in sea turtle research.

As part of his research, Limpus has led conservation efforts and significant scientific discoveries into the breeding habits of loggerhead turtles, which have been threatened by climate change, marine debris, commercial fishing, and feral predators such as foxes.

Mon Repos supports the largest concentration of nesting marine turtles on Australia’s mainland east coast and has the most significant loggerhead turtle nesting population in the South Pacific region.

The success of nesting and hatching turtles at Mon Repos is critical for the survival of the loggerhead turtle, and staff at the Mon Repos Turtle Centre work hard to protect and monitor nests, carry out research, and raise public awareness through guided tours and egg-hatchling experiences.

Limpus was on hand to share his knowledge with UQ alumni when the University visited the Mon Repos Turtle Centre and beach as part of its Regional Roadshow in November.

“There are 2 concentrations of loggerhead turtle populations in the Pacific Ocean – one is in Japan and the other is here in central eastern Queensland,” Limpus said.

By the mid 1980s, we noticed a decline in the East Australian nesting population. We found that excessive numbers of turtles were dying in Northern Australia. In 1989, we identified that bycatch [the incidental capture of non-target species due to fishing] was the issue.

“It wasn't until 2001 that the fisheries managers came to the party and introduced regulations that require turtle exclusion devices – escape hatches, really – to allow the turtles to escape instead of drowning in the nets.

“The population has increased in response to that, but there’s still a long way to go.”

Limpus said climate change has also emerged as a formidable threat to sea turtle species like the loggerhead.

“The gender of the hatchlings is actually determined by the temperature in the nest at the middle of incubation,” Limpus said.

“Females are hatched in warmer nest temperatures, while cooler temperatures produce males.

“The beaches in the Bundaberg area are about 2 to 3 degrees warmer than when we started our research in 1968. So, these days we hardly produce any males on the mainland beaches and we’re seeing a reduction in hatch success.

“A new goal for us is trying to address climate change. We can't do much about the carbon dioxide in the atmosphere – that's the role of governments. We've got to worry about how we can keep these turtle populations – which are under stress – still functioning until governments can turn the environmental issues around.”

While Limpus has received multiple awards for his service to environmental science – including a Lifetime Achievement Award of the International Sea Turtle Society in 2008 and an Officer of the Order of Australia in 2020 – some of his career highlights include helping to answer how long sea turtles live for and whether they return to the same area they were born at for breeding.

“In the 1970s, I started trying to determine the age of the turtles breeding at Mon Repos. Up until then, it was just folklore,” Limpus said.

“In those days, it was thought the turtles would take about 10 years to reach maturity. We tagged a quarter of a million hatchlings, and found they couldn’t possibly reach maturity in 10 years – it was probably going to be about 30 years or more!

“When the first tagged hatchlings came back and we saw that all those turtles were 29 years of age, I got excited.

“It was a long wait, but it’s given us basic answers that previously had only been guesswork – and we had been way out in our guesses.

“We’ve now got some turtles known to be aged in their 40s returning to the area to breed. Once they imprint on their respective feeding and nesting areas, they stay pretty faithful to those chosen sites over the years.”

On top of his research and conservation success, Limpus is also proud of the influence he has had on the younger generation of environmental scientists through his association with UQ’s School of Veterinary Science and Centre for Marine Science as an adjunct associate professor.

“I've supervised more than 60 postgraduate students over the decades. That partnership has been important for the area, and the students have benefited as well,” Limpus said

“Many of them are turning up in research and management positions and I’ve watched them succeed and grow professionally.

“My attitude from the beginning was looking after the environment, and I've always tried to encourage broader community involvement and to whet the appetite of students.”

Celebrating regional Queensland

Find out more about UQ’s Regional Roadshows and how the University is breaking down the barriers to a higher education for students across regional and remote Queensland through The Queensland Commitment.