Mapping coastal aquaculture and fisheries structures by satellite imaging radar

Carlo Travaglia
Environment and Natural Resources Service, FAO Sustainable Development Department
Via dei Gemelli, 31; I-00040 Tor Vaianica, Roma, Italy
Carlo.travaglia@libero.it

Giuliana Profeti
consultant, Remote Sensing; Via Lorenzo Viani, 98; I-50142 Firenze, Italy

Josè Aguilar-Manjarrez
, Inland Water Resources and Aquaculture Service, FAO Fisheries Department
Viale delle Terme di Caracalla, 1; I-00153 Roma, Italy

Nelson Lopez
Bureau of Fisheries and Aquatic Resources
Arcadia Building, 860 Quezon Avenue; 1103 Quezon City, Philippines

ABSTRACT

Inventory and monitoring of coastal aquaculture and fisheries structures provide important baseline data for decision-making in planning and development, including regulatory laws, environmental protection and revenue collection. Mapping these structures can be performed with good accuracy and at regular intervals by satellite remote sensing, which allows observation of vast areas, often of difficult accessibility, at a fraction of the cost of traditional surveys.

Satellite imaging radar (SAR) data are unique for this task not only for their inherent all-weather capabilities, very important as aquaculture activities mainly occur in tropical and subtropical areas, but essentially because the backscatter from the structure components allows for their identification and separation from other features.

The area selected and object of the study was the Lingayen Gulf, situated in North-western Luzon Island, the Philippines, where all these structures of interest occur. Field verification of the methodology resulted in the following accuracy: fishponds 95 percent, fish pens 100 percent. Mapping accuracy for fish cages was estimated at 90 percent and for fish traps at 70 percent.

The study is based on interpretation of SAR satellite data and a detailed image analysis procedure is described. The report aims at the necessary technology transfer for an operational use of the approach indicated in other similar environments.

Last Update: 2005-03-16