NEARSHORE FISHERIES ZONING ANALYSIS IN THE NEGROS ISLAND REGION

摘要

The Negros Island in Western Philippines is one of the regions in the Philippines that are rich in both land-based aquaculture and nearshore fish corrals. Negros Island is composed of Negros Occidental and Negros Oriental with 548.95 km2 323.63 km2, respectively of coastal area. The first part of this study was the extraction of the nearshore fish corrals In Negros Occidental using Object Based Image Analysis. The Digital Terrain Model (DTM) was used in separating water bodies from land while the Digital Surface Model (DSM) from LiDAR was used in creating the derivatives for classification which include rugosity and slope of slope. Principal Component Analysis (PCA) was performed to reduce the redundancy across DSM, slope of slope and rugosity. The feature extraction was followed by an initial suitability analysis based on weighted attributes of the extracted features in Negros Occidental. The attributes were used to reclassify the distance and depth. Euclidean distance was conducted around the surrounding area of ports, marine protected areas, reef locations and other monitored sites. The carrying capacity of the bodies of water was also considered by using the chlorophyll-a data. Each of the datasets was then reclassified with higher weights assigned to more suitable conditions depending on the criterion. A weighted overlay analysis was then applied to the different rasters in order to arrive at a suitability raster. The values contained in the raster are directly proportional to the suitability of the area in hosting the fish corrals. The whole process was then applied to the whole coastal area of Negros Island, successfully classifying suitable sites. The feature extraction component has implication on the monitoring of fish corrals when it comes to checking the correct positioning and distancing from other nearshore fisheries features and services like navigation while the site selection component will be used for determining suitable areas for the nearshore fisheries.