New research shows that culling crocodiles is an ineffective and expensive method of curbing attacks on humans.
According to a study published in the journal People and Nature, 91% of crocodile attack victims in the Northern Territory were local people. Factors contributing to this trend included human negligence and water-related activities.
Between 1979 and 2022, there were 76 crocodile attacks in the Northern Territory, 23 of which were fatal. Most of the victims were male, and the attacks occurred mainly when people ignored safety instructions or were in or near water.
The study’s lead author, Dr Cameron Baker of Charles Darwin University, said it “underscores the importance of changing human behaviour” to reduce the risk of attacks.
The researchers analyzed data from almost 50 years. During this time, the population of saltwater crocodiles grew from a few thousand to over 100,000 animals.
The analysis found that an awareness campaign called “Be Crocwise” and the relocation of problem reptiles have helped stabilize and reduce the frequency of attacks since 2009, even as the densities of crocodile and human populations have increased.
The researchers said that while crocodile attacks on humans have often led to calls for large-scale culling, there is little evidence to justify the measure as it is not an “effective and cost-efficient control strategy”.
Modeling based on the data found that 90 percent of the crocodile population would need to be eradicated to reduce the frequency of attacks by one per year. Baker said that approach would “push the species back into the critically endangered category” and could cost nearly $87.8 million.
According to study leader Hamish Campbell of Charles Darwin University, it is crucial that crocodile management is based on evidence.
“The resources available for crocodile management are limited and we need to use them as effectively as possible to reduce crocodile attacks on humans,” he said. “The evidence shows that large-scale culling is neither a cost-effective nor efficient means of doing this.”
According to ABC, crocodile policy became an issue at the recent Northern Territory election as a new crocodile management program tightens regulations for people who want to keep crocodiles as pets.
The management program, launched in April, aimed to maintain population densities of this important predator species at appropriate levels and improve public safety, while recognising that “it is an apex predator that will attack humans and that its coexistence with humans poses significant challenges to the Northern Territory community”.
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Dr Elise Furlan, a researcher at the University of Canberra who was not involved in the study, has developed a DNA test to detect the presence of crocodiles in water bodies as part of a Queensland government-funded study. She said better data could help. “If we are able to identify where crocodiles are, people can obviously change their behaviour accordingly,” she said.
The sensitive DNA water test could be another means of preventing encounters with the “cryptic species,” in addition to visual examinations from land or boat, she said.
“(They) can hide underwater and in murky waters. They are ambush predators, so they are very good at being very quiet and silent.”
Dr Vinay Udyawer, a researcher from the Australian Institute of Marine Science who contributed to the study, said the findings could be applicable to other large predators such as sharks.
“It underscores the overall ineffectiveness of culling as a primary means of damage control and the importance of alternative strategies such as education campaigns,” he said.
