A method has been discovered to keep sharks away from people: what deters these predators from beaches (photos).

The majority of unprovoked attacks by great white sharks occur near popular beaches, where these predators hunt close to the shore. Previously, scientists lacked an effective way to deter sharks from the coastline in order to reduce the likelihood of interactions with humans. However, it seems that the situation has changed, as reported by Popular Science.

In a new study, researchers found that the murky ink of cuttlefish (Sepia officinalis) may help repel sharks from hunting in areas where people swim. During the research, a team from University College Dublin created models of the olfactory systems of several shark species. The results indicate that the bioluminescent ink of cephalopods can suppress sharks' heightened sensitivity to scents.

According to the study's co-author and biologist Collin Louwless, understanding how prey species like cuttlefish have evolved to exploit specific vulnerabilities of predators such as sharks not only enhances our understanding of marine systems but also inspires the development of conservation tools based on natural processes.

It is well known that sharks are apex predators, largely thanks to their six highly developed senses:

• electromagnetism;
• vision;
• touch;
• taste;
• hearing;
• smell.

Previous studies have already shown that many species can detect the scent of blood from about 400 meters away: once predators find sources of blood, they can use their impressive jaws and muscles to tear their prey apart. However, their heightened sensitivity to scents could be their Achilles' heel.

In the new study, researchers recreated a three-dimensional model of the olfactory system of the clouded catshark (Scyliorhinus torazame) and the great white shark (Carcharodon carcharias) in the laboratory. When the scientists tested the olfactory systems of the sharks with cuttlefish ink, they discovered that melanin—the primary component—has a molecular structure that allows it to bind to olfactory receptors.

The test results suggest that melanin disrupts the sensory perception of sharks and may likely cause predators to avoid areas where the ink has been sprayed. This binding effect may also extend to all shark species, as they generally share a similar set of olfactory receptors.

The effectiveness of the ink as a natural shark repellent suggests that it could be used in conservation efforts, marine environment management, and human-shark coexistence. It is worth noting that today, methods such as gill nets and drum lines are used for shark protection. However, these methods are invasive and not only capture large sharks but also rays, dolphins, turtles, and whales.

According to Louwless, the results of their study may enable the deployment of safe and targeted repellents near beaches, aquaculture sites, or fishing areas in the future, minimizing shark encounters with humans. Furthermore, scientists believe that this method could be used to manage the movement of sharks in vulnerable areas of the ocean.