An underwater camera system for real-time coral reef fish monitoring

Abstract

With the recent progress in information communication technology, an unmanned underwater video recording system was installed for long-term monitoring of coral reef organisms, including fishes. This underwater monitoring system was established in a protected embayment near the water inlet of the Third Nuclear Power Plant in Southern Taiwan (21°57'N 120°45'E). A set of nine cameras supplemented with illuminating lights was installed ~ 3 -6 m deep on existing coral reefs. All video images taken by the underwater cameras were digitized and transmitted wirelessly to receivers in a nearby control room. The data was distributed some 300 km Northward via asymmetrical digital subscribed lines (ADSL) to the National Center for High-performance Computing (NCHC) for storage. The coral reef ecosystem is presently being continuously monitored. The 24 hour image files mirror the diurnal variations in the fishes' activities. Peaks of species occurrence were observed in the early morning (i.e., 0740 hours), one hour before noon and in the late afternoon (~ 1600 -1620 hours). By contrast, species occurrence was lower in the period between 1200 and 1500 hours. The real-time underwater images taken from different habitats were relayed by network links to distant users at ECO-GRID @ TW (http://sensor6.nchc.org.tw/). The network has been in operation since July 2004. With the introduction of this system, people are now able to watch real-time images of the amazing fishes on coral reefs via Internet broadcasting.