Satellite remote sensing of submerged kelp beds on the Atlantic coast of Canada
Underwater kelp seasonal variation is assessed through the comparative analysis of HRV and Thematic Mapper (TM) images of Baie des Chaleurs between Caps-Noirs and Pointe-Bonaventure, Quebec. The total biomass is estimated, based on the morphology of the dominant species Laminaria longicruris. Kelp-covered and kelp-free areas are differentiated from each other in water depth of 0-6 m and 0-7 m with the HRV and TM images, respectively. The median biomass estimated for the kelp-covered category of the classified image is (1500_400)g m-2. The multidate image shows a spatial variation of the kelp beds in 45% of the area. Areas where no change occurred occupy at least 70 ha, while growth and decay of kelp are observed in much smaller areas, in shallow water and at the boundary of kelp beds.