EVALUATION OF LANDSAT 7 ETM+ DATA FOR COASTAL HABITAT ASSESSMENT IN SUPPORT OF FISHERIES MANAGEMENT Randy John N. Vinluan and Jose Don T. De Alban Department of Geodetic Engineering University of the Philippines, Diliman 1101 Metro Manila, The Philippines Fax: (63 2) 9208924; E-mail: rjnv@up.edu.ph KEY WORDS: Coastal habitat, Fisheries management, Landsat 7, Mapping, Remote sensing ABSTRACT. Coastal habitats such as coral reefs, mangroves, seagrasses, and algae are important to fisheries management since these serve as indicators of fish stock, the health status of the coastal environment, and others. The suitability of Landsat 7 ETM+ data for mapping these coastal habitats was evaluated by the study. The study areas are two bays located in the province of Palawan in the Philippines, namely Puerto Princesa Bay and Honda Bay. Although adjacent to one another, the two bays actually represent different environmental conditions. Typical algorithms for the correction for the effects of water depth, radiometry, the atmosphere, and scene orientation were applied to the image. The resulting satellite image map was evaluated for visual interpretability of the coastal habitats under consideration. The appearance of these habitats, as well as that of some coastal landforms, in selected combinations of Landsat 7 ETM+ bands, is shown in the paper. Limitations in the level of habitat classification that are possible with Landsat 7 ETM+ data are also enumerated. The preprocessed satellite image was also subjected to digital classification techniques using field and other data gathered during site visits conducted in November 2000 and April 2001. Results of the classification are also discussed in the paper. 1. INTRODUCTION The agriculture and fisheries sector is one of the most important sectors in the Philippines employing about 38 percent of the total workforce and with an annual total production valued at P557.3 billion (or US$ 10.4 billion). In cognizance of the valuable contributions made by this sector to the national economy, concrete actions have been taken to address various problems concerning the development of this sector. On the fisheries side, these problems include fisheries declining, coral reefs battered, mangrove forests under threat, pollution levels rising, and coastal communities experiencing increased poverty (Courtney and White, 2000). Improved management approaches are needed in order to reduce the rate at which humans are depleting fishery populations and degrading marine ecosystems (Murray et al., 1999). The Fisheries Resource Management Project (FRMP), being implemented by the Bureau of Fisheries and Aquatic Resources (BFAR), is one such approach. FRMP aims to strengthen fisheries regulations, rationalize the utilization of fisheries resources, and rehabilitate damaged fish habitats. An essential component of FRMP is the updating of land use and coastal habitat information for the 18 bays covered by the project. These two themes are important because it has been found that impacts on land-use and coastal habitats lead to significant ecological problems such as saltwater intrusion and loss of coastal wetlands, among others (Chesney et al., 2000). In addition, it has been found that protective habitat management and habitat restoration mitigates the degradation or loss of habitat structure while maintaining healthy sustainable fisheries (Turner et al., 1999). Coastal habitats themselves serve as indicators of fish stock, the health status of the coastal environment, and others. It is a well-known fact that remote sensing plays an important role in the mapping of such themes. Literature reports the use of aerial photographs and multispectral data, and Landsat MSS/TM and SPOT XS/Pan images for coastal land use and habitat mapping with varying degrees of success (e.g. Zainal et al., 1993; Maritorena, 1996; Chauvaud et al., 1998). This study evaluates the suitability of the latest satellite in the Landsat series, namely Landsat 7, for coastal habitat mapping. The satellite carries a new sensor called Enhanced Thematic Mapper (ETM+), which is an improvement over the Thematic Mapper sensor carried by Landsat 4 and 5. For a detailed technical description of the Landsat 7 mission, one is referred to the special issue of Earth Observation Magazine on Landsat 7 that came out in March 1999 or to the Landsat Program Web site (URL: geo.arc.nasa.gov/esdstaff/landsat/tofc.html). The study area is Puerto Princesa Bay and Honda Bay, both located at the eastern side (Sulu Sea-side) of Puerto Princesa City, the capital of the province of Palawan in the Philippines. Although adjacent to one another, the two Paper presented at the 22nd Asian Conference on Remote Sensing, 5 - 9 November 2001, Singapore. Copyright (c) 2001 Centre for Remote Imaging, Sensing and Processing (CRISP), National University of Singapore; Singapore Institute of Surveyors and Valuers (SISV); Asian Association on Remote Sensing (AARS) ____________________________________________________________________________________________