Appendix
Table 1. Optical Vs Radar satellite imagery
Optical satellite imagery
Radar satellite imagery (SAR)
Adapted to the human eye (user-friendly)
Can be analysed at a glance
Gives colour images
Does not require powerful development to
obtain a picture
Not dependent on the weather (cloudy, rainy
Adapted to EEZ area down to vessel size
Allows for multi-sources data merging (e.g. VMS
& AIS)
Gives cheaper results
Makes forecasting easier
Fisheries monitoring is conventionally based on
VMS data. However IUU perpetrators habitually
spoof/disable VMS/AIS messages to inhibit the
identification and traffic of vessels operating
illegally. The use of detection by satellite radar
images enables to detect the location of vessels
not transmitting
Makes multi-constellations and sensors available
on board according to the type of data
requested. New generation satellites have a very
frequent revisiting time, a very high resolution/
precision and a more reliable and versatile
system. (e.g. RADARSAT-2, Sentinel-1A, COSMO
SkyMed, TerraSAR-X)
Severely affected by weather conditions (cloud,
fog or night)
More expensive (according to accuracy
expected, can be twice)
Hard to predict because it depends on the
weather forecast
Complementary analysis and interpretation are
needed for a “non-expert” reading
Black and white image
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