This inserted picture has been taken from a publication by Auburn University (USA) published on December, 1970. Being an Auburn University Alumni, I decided to share this picture along with the description: “Pond culture with Biological Filters: Water, pumped from a pond where fish are fed, is filtered through gravel covered with living microscopic organisms then returned through a gravity flow system. The photo shows a filter in the background, some of the ponds in services, the water return system in the foreground. With this system production of 10,000 pounds of catfish per acre in approximately 6 months has been obtained. Practical applications of the system are now being studied”.
