Using an underwater camera to monitor real-time fish activities

A project was carried out using an underwater camera and instrumentation system for monitoring fish species activity on an inshore coral reef in the Hoi Ha Wan Marine Park, Hong Kong. The system consists of a high-resolution pan, tilt, and zoom camera with associated lighting, and an instrumentation package for measuring the local environment, including dissolved oxygen, temperature, pressure, and salinity. It uses bidirectional communication through an underwater cable with two multi mode optical fibers, providing one video channel and a forward and backward digital transmission for the camera, sensors, and lighting control. Additional lighting for night-time recording was provided by a light emitting diode (LED) light controlled via the communications system, in additional to two higher intensity lights. This method for monitoring fish behavior and identifying specific fish species data is more sensitive as compared to the more commonly used scuba diver methods.