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Figure 3. Underwater photos of megalitter recovered by the ROV. References

Figure 3 Underwater photos of megalitter recovered by the ROV. References

Related Figures (2)

Figure 1. (a) iUSV170 used for the benthic megalitter survey, (b) USV operates off the Thessaloniki Port close to the surface support vessel MV TY PHOON. target map was created using IC5 values greater than 0.5 (Fig. 2c). The spatial distribution of the targets is characterized by homogeneity. Slightly higher spatial density is observed at the eastern part of the survey area, close to the breakwater (Fig. 2c). The target size distribution is bimodal presenting two local maximums; a primary at 0.6m and a secondary at 1.5m (Fig. 2d). Thirty three targets, a significant percentage (59%) of the population, have similar dimensions, between 0.5 and 0.7m (Fig. 2d). Only seven targets (12.5%) greater than 1 m was detected in the survey area (Fig. 2d). The ground truthing survey showed that the water column of the area is characterised by high turbidity and poor visibility conditions and therefore the detection and the identification of the targets is a challenging task. Nonetheless, the visual inspection of many targets showed that represent man-made items like metallic pieces, car tires, wires, e.t.c. (Fig. 3). Moreover, the inspection revealed the colonization and encrustation of marine litter by marine biota.
Figure 1. (a) iUSV170 used for the benthic megalitter survey, (b) USV operates off the Thessaloniki Port close to the surface support vessel MV TY PHOON. target map was created using IC5 values greater than 0.5 (Fig. 2c). The spatial distribution of the targets is characterized by homogeneity. Slightly higher spatial density is observed at the eastern part of the survey area, close to the breakwater (Fig. 2c). The target size distribution is bimodal presenting two local maximums; a primary at 0.6m and a secondary at 1.5m (Fig. 2d). Thirty three targets, a significant percentage (59%) of the population, have similar dimensions, between 0.5 and 0.7m (Fig. 2d). Only seven targets (12.5%) greater than 1 m was detected in the survey area (Fig. 2d). The ground truthing survey showed that the water column of the area is characterised by high turbidity and poor visibility conditions and therefore the detection and the identification of the targets is a challenging task. Nonetheless, the visual inspection of many targets showed that represent man-made items like metallic pieces, car tires, wires, e.t.c. (Fig. 3). Moreover, the inspection revealed the colonization and encrustation of marine litter by marine biota.
Figure 2. (a) SSS mosaic showing the Acoustic Backscatter Patterns (A BP), (b) the Independent Component 5 (IC5) highlighting targets, (c) final target map based on IC5>0.5 and (d) target size distribution based on the equivalent diameter of the target boundaries.
Figure 2. (a) SSS mosaic showing the Acoustic Backscatter Patterns (A BP), (b) the Independent Component 5 (IC5) highlighting targets, (c) final target map based on IC5>0.5 and (d) target size distribution based on the equivalent diameter of the target boundaries.
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Marine And Environmental Pollution
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