Mapping Coastal Aquaculture and Fisheries Structure by Satellite Imaging RadarCase Study of the Lingayen Gulf Philippines

Carlo Travaglia1, Giuliana Profeti2, Jose Aguilar-Manjarrez3, Nelson Lopez4

1 Environment and Natural Resources Service, FAO Sustainable Development Department, Rome, Italy2 SAR Image Processing, Florence, Italy3 Inland Water Resources and Aquaculture Service, FAO Fisheries Department, Rome, Italy4 Inland Fisheries and Aquaculture Division, Bureau of Fisheries and Aquatic Resources, Manila, Philippines

Presented at the Shangri-la Hotel, EDSA, Philippines for the Asia Pacific Advanced Network Conference (APAN) 2007.

Background

Philippines ranked 8th among the top fish producing countries in the world

Fisheries production of 4.163 million MT (2.8%) out of the total world production of 146.27 million MT in 2005

Philippines ranked 11th in the world for aquaculture production

Aquaculture production of 1.89 million MT (4.5%) out of the global aquaculture production of 42.3 million MT

2nd largest producer of aquatic plants at 1.39 million MT or 11.58% of the total world production at 12 million MT

Aquaculture sector posted the highest percentage share of 46% (1.895 million MT) and growth rate of 10.41%

Posted 6% growth rate from the previous year and is valued at US$2.92 billion

Aquaculture sector is valued at US$ 983.4 million

4.3% contribution to the GDP

Significance of the Study

Inventory and monitoring of coastal fisheries structures are essential tools for Aquaculture Development:

• Planning• Regulatory Management• Economic Valuation • Policy Formulation • Environmental Protection• Revenue Generation

Up-to-date information on the spatial distribution of structures to enforce development regulations, to ensure productive environment

It is aimed at the general fisheries and aquaculture public, governmental administrators and planners and remote sensing and GIS specialists.

Objectives

Develop and field test a methodology for the inventory and monitoring of coastal aquaculture and fisheries structures using satellite imaging radar (SAR)

Evaluate the accuracy of SAR-based geospatial assessment of minute aquaculture infrastructure

Identify a study area where all target structures under study are present

Description of the Test Area

Lingayen Gulf is located at the northwestern coast of Luzon Island at 16 and 17 N and 119 and

The gulf is a semi-circular embayment enclosing an area of 2,100km2

160 km of coastline from Cape Bolinao to Poro Point

Five major rivers drain into the gulf: Bauang, Aringay, Patalang-Bued, Dagupan, and Agno.

12,000 fishers and 7,000 boats in 18 coastal municipalities

CPUE stands at 1kg/fisher/day

16,000 hectares of fishponds in La Union and Pangasinan

Study Areas and Zones covered by the Satellite Data

Fish Pen

Fish Cages

Fish Traps

Topographic Maps Covering the Study Area (Scale 1:50,000)

Vectorial Maps obtained from the topographic mapsTopographic Maps 1:50,000 1977

Portion of Dagupan City Topographic Map (Sheet 7074 II) and the derived vector data.

Angle between the scanning directions in the SAR data used in the study

Interactions of radar beams with a fish cage

Sea state and coastal aquaculture and fisheries structures mapping

Characteristics of the satellite data usedImage type, pixel size Orbit, frame Heading, path Acquisition date Corner coordinates

(degrees from North) (year/month/day) N EUL 16.54 119.48UR 16.73 120.39

39830, 315 347.348 ascending 2002-12-02 LR 15.82 120.58

ERS-2 SAR GEC1 LL 15.64 119.6812.5 x 12.5 m

UL 16.52 119.84UR 16.33 120.74

40123, 3285 192.640 descending 2002-12-23 LR 15.42 120.54LL 15.61 119.64

UL 16.45 119.84RADARSAT-1 SAR UR 16.54 120.30

SGF2 27423, 347.318 ascending 2001-12-24 LR 16.04 120.40

6.25 x 6.25 m path image3 LL 15.95 119.94

1Ellipsoid Geocoded image2SAR Georeferenced Fine Resolution3Floating along-track between two frames

UL=Upper LeftUR=Upper RightLR=Lower Right

Characteristics of the satellite data used

Class Name NotesSalt pans 2002 No apparent changes from the extension mapped in 1977Fishponds 2001 and 2002 Identified both on RADARSAT-1 and on the two ERS imagesFishponds 2001 and 2002, uncertainIdentified on one image only, out of two or three (where available)Fish pens 2001 Identified on RADARSAT-1 dataFish pens, uncertain No assignments to this classFish cages 2001 Identified on the RADARSAT-1 imageFish cages 2001, uncertain May be a small island or a rough patch in the sea surfaceFish cages 2002 Identified on the ERS-2 imagesFish cages 2002, uncertain May be a small island or a rough patch in the sea surfaceAreas with fish traps in the open sea 2001Polygons drawn around the areas on which fish traps wereAreas with fish traps inside rivers 2001detected to have an approximate estimation of their extensionMainland, high tide Coastline at high tide, obtained from RADARSAT-1 (2001/02/04) and the ERS-2 image acquired on (2002/12/02)Islands (open sea) Islands inside the major rivers are not included

RESULTS

Classes identified in the SAR Images: Polygon Layer

RESULTS

Total area covered by the classes of interest (Pangasinan Province)

Total area covered by the classes of interest (Pangasinan province

Number of units

Total Area

(km2)Class descriptionSalt pans 2002 1 4.156Fishponds 2002 587 157.723

Fishponds 2002, uncertain1 33 2.036Fish pens 2001 22 1.600Fish cages 2001 105 2.439

Fish cages 2001, uncertain2 7 0.054Fish cages 2002 267 1.390

Fish cages 2002, uncertain2 16 0.019

Areas with fish traps in the open sea, 20013 12 18.943

Areas with fish traps inside rivers, 20013 6 1.703

1Identified in image only, out of two or three.2Uncertain assignment: maybe a small island or a rough patch in the sea surface

Class descriptionNumber of elements

Cumulative length (km)

Average length (km)

Minimum length (km)

Maximum length (km)

Standard deviation

Traps in the open sea 378 50.104 0.133 0.018 0.642 0.093Traps inside rivers 64 7.886 0.094 0.024 0.364 0.061

RESULTS

Length of Fish Traps detected in the area

Comparison of visual interpretation and in situ observations on the verification points

Location Visual interpretation In situ verification1 Zarragosa, Bolinao Salt pans; fishponds across the river, south of the verification pointSalt pans; fishponds across the river, south of the verification point2 Zarragosa, Bolinao Salt pans Salt pans3 Lambes, Bani Fishponds Fishponds4 Lambes, Bani Salt pans Salt pans5 Bgy. Banog Norte, Bani Fishponds Fishponds6 Bgy. Banog Norte, Bani Fishponds Fishponds7 Pangapisan, Alaminos Fishponds on both embankments of Embarcadero RiverFishponds on the north embankment of Embarcadero River; thin strip of residential area along the south embankment with fishponds behind it8 Bani-Alaminos boundary, still a part of Bgy. PangapisanFishponds Marshland adjacent to salt pans in the north. Saltpans due south, converted to fishponds during the rain season9 Bgy. Banog Norte, Bani Fishponds Fishponds

10 Bgy. Banog Norte, Bani Fishponds Fishponds11 Bgy. Banog Norte, Bani Fishponds Fishponds12 Bgy. Banog Norte, Bani Fishponds Fishponds13 Bgy. Banog Norte, Bani Fishponds Fishponds14 Bgy. Banog Norte, Bani Fishponds Fishponds15 Bgy. San Miguel, Bani Fishponds Fishponds16 Bgy. San Miguel, Bani Fishponds Fishponds17 Bgy. Calmay, Dagupan City Fishponds Fishponds18 Bgy. Calmay, Dagupan City Fishponds Fishponds19 Bgy. Canaoalan, Biec East, Binmaley Fishponds Fishponds20 Bgy. Canaoalan, Biec East, Binmaley Fishponds Fishponds21 Bgy. Dulig, Lingayen Fishponds Fishponds22 Bgy. Dulig, Lingayen Fishponds Fishponds23 Bgy. Basing, Binmaley Fishponds Fishponds24 Bgy. Basing, Binmaley Fishponds Fishponds25 Bgy. Basing, Binmaley Fishponds Fishponds26 Bgy. Basing, Binmaley Fishponds, uncertain Swamp area27 Bgy. Socony, Lingayen Fishponds, uncertain Water impoundment28 Bgy. Socony, Lingayen Fish pens Fish pens29 Bgy. Pugaro, Dagupan City Fish pens Fish pens30 Bgy. Pugaro, Dagupan City Fish pens Fish pens31 Bgy. Pantal, Dagupan City Fish pens Fish pens32 Bgy. Pantal, Dagupan City Fish pens

Field verification analysis

Fishpond 95%

Fish Pens 100%

Fish Cages 90%

Fish Traps 70%