This study presents a semi-automatic method to estimate fan surface of a
Placogorgia sp. octocoral assemblage using 3D point clouds in El Cachucho
MPA at 550 m of depth.
The semi-automatic methodology uses fitting planes to assess colonies
morphometries. Using Pix4D Mapper Pro and Cloud Compare software, size
and morphometry of fan-shaped gorgonians and forest population structure were
assessed. RMS of fitting planes shows that the geometrical figure chosen is
suitable to retain the morphometric characteristics of the specimens of this
species.
The adjustment of semi-automatic values with a sample of manually digitized
surfaces is validated (R2=0.97). The results show that gorgonian population was
mostly dominated by small colonies. The population structure distribution
shows a high proportion (~22%) of recruits (< 0.05 m2
) of fan surface
