É. L. Simms
504
Non-metric statistical analyses were applied to the field data collected
throughout the area classified as dense kelp beds. The median, quartile, and notches
were identified with the objective of defining the characteristics of a dense kelp bed
where canopy coverage is 100 %. The median represents the centre value of the
distribution, and the hinges delimit the range covered by the middle half of the data.
The notches define the group of values that represents the distribution with 95 %
confidence level (Velleman and Hoaglin, 1981). The biomass was estimated with
Equation 1 as follows:
B = AW
(1)
Where B is the total biomass estimate in kg, A is the kelp covered area classified on the
image, and W is the median biomass value derived from the quantitative survey in
Results and Discussion
The bottom type image displayed three groups (Figure 1). The class representing the
dense kelp canopy was classified in water depth of less than 5 m. A few isolated pixels
of that class distributed in deeper water, suggested that the image radiometric noise
caused a misclassification. A 3x3 mode filter eliminated the isolated pixels without
modifying the proportion of pixels in each class. The first category occupies 80% of the
area classified with 95.7 ha. The second and third categories, representing the kelp
beds, are shown on Figure 2. They include respectively, 9% (10.7 ha) and 11% (13.7
ha) of the area analyzed.
The species inventoried in the study area were Alaria esculenta, Desmarestia
viridis, Fucus spp., Laminaria digtata, and Laminaria longicruris. Alaria esculenta
dominated in eleven of the fourteen quadrants surveyed, closely followed by Laminaria
sp., that was found in ten quadrats.
504
Non-metric statistical analyses were applied to the field data collected
throughout the area classified as dense kelp beds. The median, quartile, and notches
were identified with the objective of defining the characteristics of a dense kelp bed
where canopy coverage is 100 %. The median represents the centre value of the
distribution, and the hinges delimit the range covered by the middle half of the data.
The notches define the group of values that represents the distribution with 95 %
confidence level (Velleman and Hoaglin, 1981). The biomass was estimated with
Equation 1 as follows:
B = AW
(1)
Where B is the total biomass estimate in kg, A is the kelp covered area classified on the
image, and W is the median biomass value derived from the quantitative survey in
Results and Discussion
The bottom type image displayed three groups (Figure 1). The class representing the
dense kelp canopy was classified in water depth of less than 5 m. A few isolated pixels
of that class distributed in deeper water, suggested that the image radiometric noise
caused a misclassification. A 3x3 mode filter eliminated the isolated pixels without
modifying the proportion of pixels in each class. The first category occupies 80% of the
area classified with 95.7 ha. The second and third categories, representing the kelp
beds, are shown on Figure 2. They include respectively, 9% (10.7 ha) and 11% (13.7
ha) of the area analyzed.
The species inventoried in the study area were Alaria esculenta, Desmarestia
viridis, Fucus spp., Laminaria digtata, and Laminaria longicruris. Alaria esculenta
dominated in eleven of the fourteen quadrants surveyed, closely followed by Laminaria
sp., that was found in ten quadrats.