(MCD) in St. Thomas, USVI, the Mutton Snapper and Lang Banks, in St. Croix, USVI
(Geophysics GPR International, 2003) were included as GIS layers on the deep reef atlas.
A georeferenced TIFF file of side-scan sonar images of Bajo de Sico in Mona Passage, PR,
available from DNER (2003), was incorporated into the map atlas. Georeferenced
bathymetry data for Bajo de Sico and Isla Desecheo (García et al., this volume) were
converted to Geo - TIF files and included in the general map. Hydrographic (CTD) data from
profiles produced by the Johnson Sea Link submersible survey of the insular slope of PR
and the USVI (Nelson and Appeldoorn, 1985) were graphed and included as GIF files into
the map. Information from the deep water snapper/grouper exploratory fishing program in
PR and the USVI (NMFS-NOAA) was also incorporated into the atlas. All stations were the
catch of either ssnapper or grouper exceeded 20 pounds were plotted on the map. Results
of the biological survey at Isla Desecheo (García et al., this volume) were also included in
the map.
C. Field Survey at Isla Desecheo
1. Sessile-benthic communities
A quantitative and qualitative characterization of the upper slope reef communities at Isla
Desecheo was performed. The survey area is located off the Puerto Canoas coast,
southwest Isla Desecheo. Sets of six (6) permanent 10 m long transects were established
at depths of 30 and 40 meters along the SE Wall Reef and a total of eight (8) nonpermanent transects were surveyed at Agelas Reef, at a depth of 50 m. Transects were
marked using steel rods drilled to the ocean floor and identified with (plastic) cable ties
secured to the steel rods. Quantitative determinations of surface cover by sessile-benthic
biota were obtained from video transects using a Sony VX 2100 video camera with a Gates
underwater housing. A stainless steel rod with an extension of 76 cm (30 inches) beyond
the camera housing lens plate was assembled to the housing to maintain a constant
camera-subject distance during filming.
Continuous profiles of benthic communities along video transects were analyzed. Videos
from each transect were saved as frozen frames (jpg files) in a computer. A random point
template of 25 (x, y) points was superimposed on each frame, and substrate categories
under the points were identified and recorded. For each transect, a total of 625
identifications of substrate categories were included.
12
(Geophysics GPR International, 2003) were included as GIS layers on the deep reef atlas.
A georeferenced TIFF file of side-scan sonar images of Bajo de Sico in Mona Passage, PR,
available from DNER (2003), was incorporated into the map atlas. Georeferenced
bathymetry data for Bajo de Sico and Isla Desecheo (García et al., this volume) were
converted to Geo - TIF files and included in the general map. Hydrographic (CTD) data from
profiles produced by the Johnson Sea Link submersible survey of the insular slope of PR
and the USVI (Nelson and Appeldoorn, 1985) were graphed and included as GIF files into
the map. Information from the deep water snapper/grouper exploratory fishing program in
PR and the USVI (NMFS-NOAA) was also incorporated into the atlas. All stations were the
catch of either ssnapper or grouper exceeded 20 pounds were plotted on the map. Results
of the biological survey at Isla Desecheo (García et al., this volume) were also included in
the map.
C. Field Survey at Isla Desecheo
1. Sessile-benthic communities
A quantitative and qualitative characterization of the upper slope reef communities at Isla
Desecheo was performed. The survey area is located off the Puerto Canoas coast,
southwest Isla Desecheo. Sets of six (6) permanent 10 m long transects were established
at depths of 30 and 40 meters along the SE Wall Reef and a total of eight (8) nonpermanent transects were surveyed at Agelas Reef, at a depth of 50 m. Transects were
marked using steel rods drilled to the ocean floor and identified with (plastic) cable ties
secured to the steel rods. Quantitative determinations of surface cover by sessile-benthic
biota were obtained from video transects using a Sony VX 2100 video camera with a Gates
underwater housing. A stainless steel rod with an extension of 76 cm (30 inches) beyond
the camera housing lens plate was assembled to the housing to maintain a constant
camera-subject distance during filming.
Continuous profiles of benthic communities along video transects were analyzed. Videos
from each transect were saved as frozen frames (jpg files) in a computer. A random point
template of 25 (x, y) points was superimposed on each frame, and substrate categories
under the points were identified and recorded. For each transect, a total of 625
identifications of substrate categories were included.
12