Drones that can track sharks while posing little threat to aviation can save lives
Australians are increasingly paying attention to the risks animals can pose after another swimmer was seriously injured by a shark on Saturday, this time at Sydney’s Coogee Beach. There’s no doubt that shark encounters with humans are increasing, but it’s not entirely clear why. The bigger question is how best to reduce shark bites.
Human shark interactions involve two parties: humans and sharks. We need to manage both. There are no doubt more people on the water throughout the year, which alone explains much of the increase in solo encounters.
It’s June and the water temperature around Sydney is still between 18 and 19 degrees; If you’re wearing a short western outfit, it’s quite comfortable for most water sports. Even though it’s winter, there are still a lot of people in the water. After all, Saturday was gloriously sunny.
The impact of climate change on sharks’ behavior is less well known, but it is clear that their distribution is changing on a wider scale. Most sharks try to maintain a comfortable thermal envelope because, unlike mammals that generate their own heat, a shark’s body temperature is determined by the temperature of the water. White sharks prefer the cooler side (15 to 22 degrees), while bull sharks prefer warmer waters (22 to 28 degrees). So climate change is causing changes in human and shark behavior, which increases unpredictability and will require rethinking about how best to manage this conflict.
We often hear in the media and elsewhere that shark numbers are increasing. For the most part, scientific evidence does not support this. The top three species targeted for management in Australia are (whites, bulls and tigers) numbers are listed for protection purposes because decreasing. Accordingly, they are vulnerable, defenseless and almost threatened, respectively. International Union for Conservation of Nature.
Therefore, a sensible management approach should be one that allows us to coexist with these animals without putting them (or us) at further risk.
We also need to be much more aware of the real risk sharks pose to humans. The death rate from shark bites in Australia is approximately two to three people per year. The long-term trend is slightly increasing, but this is a very patchy data set. Some years there are no deaths, and in subsequent years there will be clusters. However, the risk is extremely low given that millions of Australians are at sea throughout the year.
In fact, the risk is so low that it’s worth questioning how much money we’re investing in managing the perceived “shark threat.” Most of the deaths are surfers or spearfishers. To some extent this is a numbers game; The more time you spend in the water, the more likely you are to encounter a shark. But if bitten, the most important thing that determines survival is how quickly the victim gets help. This help was immediate and life-saving for the swimmer in Coogee on Saturday.
It is also worth noting that sharks do not eat humans, but sometimes bite them out of self-defense, mistaken identity, or curiosity.
What is clear is that we need to move away from age-old approaches (nets and drum lines, mostly aimed at reducing shark numbers) towards ensuring we can coexist with sharks. drones It will play an important role, but we have made little use of this technology to date.
A ban on drones was temporarily lifted on Sunday as commercial airlines were in the flight path at Coogee to allow Surf Life Saving NSW to scan the area for sharks. But we live in the age of artificial intelligence, where drones can be programmed to fly alone and automatically track and recognize sharks. They can report to the ground station and sound an alarm to pull people out of the water. They may even deploy other drones to escort water users to shore. This is where the future lies. Yes, there are some concerns about where drones might fly, but they are unlikely to pose a serious risk to commercial aircraft if they fly at low levels. Some of this legislation needs to be reviewed.
Shark nets catch almost no target species and indiscriminately kill non-target threatened species such as whales, dolphins and turtles. Non-target prey outweighs target prey by at least ten times. To put it briefly, the environmental impact of networks is huge and the benefits are almost negligible. Analysis suggests that networks are not significantly increase security on the beaches.
NSW is moving from drum lines, where baited hooks ensnare and drown sharks, to smart drum lines that alert when sharks are hooked, allowing them to be released with a tag unless they are already tagged. Many do. The survival rate of sharks in smart line captures is much higher and the wider ecological impact is significantly reduced. NSW Department of Primary Industries reports show smart barrels and drones becoming commonplace much more effective in detecting three target shark species. The state government is rightfully investing in this approach.
We are also making good progress on: personal deterrents. Some technologies that produce electromagnetic fields around the swimmer or surfer deter sharks to varying degrees. There are other efforts to reduce accidental bites by lighting the underside of surfboards to break up the silhouette.
More investment is needed to understand shark behavior and why sharks bite humans so we can create effective targeted solutions. Some of these solutions are staring us right in the face; we just need to embrace them.
Professor Culum Brown is head of the Macquarie University Fish Laboratory.
Professor Culum Brown is head of the Macquarie University Fish Laboratory.
