Self Catching Fish

Researchers at the Marine Biological Laboratory 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. If it works, the system could eventually allow black sea bass to be released into the open ocean, where they would grow to market size, then swim into an underwater cage to be harvested when they hear the signal.

"It sounds crazy, but it's real," said Simon Miner, a research assistant at the Marine Biological Laboratory at Wood's Hole, which received a $270,000 grant for the project from the National Oceanic and Atmospheric Administration.

Mr Miner said the first step in the project was to establish whether fish could be trained. Fish, including black sea bass, stout and bottom-dwelling fish, were kept in a circular tank and fed in an enclosed feeding area within the tank.

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.

In May, scientists will expand the experiment by bringing about 5,000 black sea bass to a feeding station called an AquaDome in Buzzards Bay, 45 miles south-east of Boston. The fish will be fed in a dome after a sound broadcast and, when sufficiently "trained", will eventually be freed.

Two days later researchers will then sound the tone to see if they return. But fish farmers will take some convincing before they adopt this system.

"The commercial side is going to be sceptical," said Randy MacMillan, the president of the National Aquaculture Association in America.

"My experience with fish is they will wander far and wide," he added.

Source: Telegraph, via Noorderlicht, thanks Daniël Dennis.