Researchers at the Marine Biological Laboratory (MBL) at Wood’s Hole, Massachusetts, are testing a plan to train fish to catch themselves by using a sound broadcast to attract them into a net. They hope to release fish into the open ocean, where they would grow to market size, before enticing them into an underwater cage to be harvested when they hear a tone that signals feeding time.
If successful, the system could be used to bolster depleted fish stocks and reduce the costs of fish farming, scientists said. “It sounds crazy, but it’s real,” said Simon Miner, a research assistant at MBL. Mr Miner said the first step in the project was to establish whether fish could be trained.
Scientists would sound a tone before they dropped food into the feeding area, which the fish could enter through a small opening. The tone was played for 20 second, three times a day, for about two weeks. The result, according to Mr Miner, was “remote-control fish”. “You hit that button and they go into that area and they wait patiently,” he said. Mr Miner is now trying to determine how the fish remember to associate the sound with food.
He said the fish were fed outside the feeding zone for a few days, and then the tone was reinstated to see if they would return to the feeding area. Some fish forgot after five days, while others remembered for as long as 10, Mr Miner said.