Every now and then it's fun to think on other forms of music and sound, like the sounds in nature that we humans take for granted, especially when we don't always see the effects of their absence.  Coral reefs throughout the world's oceans are in trouble.  Once a reef has died due to some environmental imbalance, even if conditions improve, the fish, shrimp and other creatures that populate a living reef won't return to an abandoned reef. 

       University of Exeter marine biologist Tim Gordon had a theory.  In the ocean fish are the first to jump start a fledgling ecosystem.  The reason may make you turn up your nose, but turns out that fish urine, which contains nitrogen and phosphorus, is good for the health of a coral reef.  A healthy reef will then attract other species which further restores the system. Dr. Gordon decided to try to lure the fish to an abandoned reef by using recorded sounds from a healthy reef broadcast via speakers placed around the vacant reef.  It worked!  The number of fish around the reef increased by 50%!  As to the fishy sounds, Dr. Gordon says, "Clownfish whoop, and cod grunt.  Parrotfish crunch their way through coral as they graze ...sea urchins scrape, and shrimp snap their claws. Together, that makes a symphony of reef noise that fish can hear from miles away."   The fish come back followed by all those small but noisy species that make the reef snap, crackle and pop like a pan of sizzling bacon. 

Listen here for what the fish hear.