On 2008-03-26, Mike wrote:

Scientists are testing a plan to train fish to catch themselves by
swimming into a net when they hear a sound that means feeding time.

Not exactly a new idea. OR tried a variation of this decades ago. Raise
salmon in landlocked pools (like a huge swimming pools) on the Pacific Coast
with a canal to the sea. Let salmon go to sea when ready and return to
pen/pool when ready. This was back when aquaculture was in its infancy. I
didn't follow on how well it worked out.

nb