Most sharks feed on fish, crustaceans, molluscs, plankton and other marine mammals. For fishermen, sharks can be a problem, sometimes they find huge sharks in their nets and try to steal a day's catch. Although sharks can usually be safely removed from traps, this can be a very difficult process.
According to a study by researchers at Newcastle University, sharks can be driven out of the net by magnets. A small magnet placed near the trap inlet creates a magnetic field around the opening. In the set of more than 1,000 traps, the researchers found that sharks with magnets were 30% less than sharks caught by sharks without magnets. In addition, because fewer sharks are attracted, more fish are caught – a great surprise for fishermen.
Why does the magnet repel the shark?
The task of American chemist Eric Stroud is to find an effective insect repellent for sharks after the summer. He said: "In the ocean of Florida, all creatures are attacked by sharks." He built a small pool in the basement filled with water and raised some sharks. He observed the behavior, eating and interaction of the shark until one day he accidentally dropped a magnet near a pond. The nurse shark flew away, avoiding the area near the magnet.
Sharks have a very convenient electronic sensor called the Lorenzini ampulla. These electroreceptors are small pores on the shark's nose. Scientists believe that sharks not only use the Earth's magnetic field to navigate, but also the prey's heartbeat. These rotating magnets can interfere with their senses, causing them to lose their sense of direction.
Stroud's experiment did not seem to affect other species such as tuna, swordfish and crabs. The same situation can have a potential impact on sea turtles like sharks because they use the Earth's magnetic field to return to the beach where they lay eggs and hatch them.
We are very happy that the fishermen have found a safe way to drive the sharks, and we are especially grateful that this is a magnetic solution!