abundance over significant areas (measuring 10 s of square kilometres). For
example, in the Miami Terrace, this approach shows that coral habitats cover up to
76 % of the observed ridges (*13 km
2 ). Submersible observations indicate,
however, that many of the ‘coral thickets’ detected using backscatter at this site are
dead colonies. In contrast, submersible ground-truthing reveals a higher proportion
of live corals at the GBB site, but that their distribution is restricted to isolated
mounds. These examples demonstrate that submersible ground-truthing is critical
for validating the outputs of remote sensing tools. Further, ‘coral thickets’ identified by the presented remote sensing workflow should be interpreted as standing
coral thickets (live and dead), and not as a measure of live coral cover.
The integrated survey approach and quantitative data analyses described here
have significant applications for characterizing cold-water coral ecosystems. We
recommend the selection of representative sites throughout regions known to
contain cold-water coral ecosystems for the acquisition of high-resolution baseline
datasets, followed by long-term monitoring. Each recommended survey effort
should include preliminary large-scale mapping using hull-mounted multi-beam
systems to detect and/or confirm the extent and distribution of coral habitats at
regional scales. Sites selected for monitoring should then be mapped using an
AUV for morphological characterization of coral features. These AUV maps can
also be used for accurately planning ground-truthing surveys using submersible or
ROV platforms. All geo-referenced data should then be integrated in a GIS system
in order to produce comprehensive coral habitat maps. Quantitative analyses can
then be performed on these maps to systematically calculate coral abundance and
distribution. These baseline assessments of cold-water coral habitats can critically
inform long-term monitoring programs and policy efforts, such as the designation
of Habitat Areas of Particular Concern (HAPCs) and Essential Fish Habitats
(EFHs). Additional surveys of each designated site can then be performed and
compared to baseline datasets in order to track site condition, particularly following exposure to acute (e.g., bottom trawling) and/or chronic (e.g., ocean
acidification) disturbances. The application of high-resolution remote sensing and
ground-truthing tools to the management of cold-water coral ecosystems represents a critical step forward in our ability to identify and protect these valuable
ecosystems.
Acknowledgments The authors thank NOAA Oceans Explorer program for AUV ship time, as
well as C&C Technologies, the crew of the R/V Northern Resolution, R/V Seward Johnson, and
the JSL-II submersible. A grant provided by the State of Florida, Medicines from Florida’s
Oceans Project (HBOI Project # S2156, S2168) provided funding for the submersible cruises. We
also thank David Viggiano for current data processing, and John K. Reed for his input on the
manuscript. Post-cruise analyses are supported by the American Chemical Society Petroleum
Research Fund (#49017ND8) and by the Industrial Associates of the Comparative Sedimentology
Laboratory (CSL) at the University of Miami.
10 Deep Acoustic Applications
279
example, in the Miami Terrace, this approach shows that coral habitats cover up to
76 % of the observed ridges (*13 km
2 ). Submersible observations indicate,
however, that many of the ‘coral thickets’ detected using backscatter at this site are
dead colonies. In contrast, submersible ground-truthing reveals a higher proportion
of live corals at the GBB site, but that their distribution is restricted to isolated
mounds. These examples demonstrate that submersible ground-truthing is critical
for validating the outputs of remote sensing tools. Further, ‘coral thickets’ identified by the presented remote sensing workflow should be interpreted as standing
coral thickets (live and dead), and not as a measure of live coral cover.
The integrated survey approach and quantitative data analyses described here
have significant applications for characterizing cold-water coral ecosystems. We
recommend the selection of representative sites throughout regions known to
contain cold-water coral ecosystems for the acquisition of high-resolution baseline
datasets, followed by long-term monitoring. Each recommended survey effort
should include preliminary large-scale mapping using hull-mounted multi-beam
systems to detect and/or confirm the extent and distribution of coral habitats at
regional scales. Sites selected for monitoring should then be mapped using an
AUV for morphological characterization of coral features. These AUV maps can
also be used for accurately planning ground-truthing surveys using submersible or
ROV platforms. All geo-referenced data should then be integrated in a GIS system
in order to produce comprehensive coral habitat maps. Quantitative analyses can
then be performed on these maps to systematically calculate coral abundance and
distribution. These baseline assessments of cold-water coral habitats can critically
inform long-term monitoring programs and policy efforts, such as the designation
of Habitat Areas of Particular Concern (HAPCs) and Essential Fish Habitats
(EFHs). Additional surveys of each designated site can then be performed and
compared to baseline datasets in order to track site condition, particularly following exposure to acute (e.g., bottom trawling) and/or chronic (e.g., ocean
acidification) disturbances. The application of high-resolution remote sensing and
ground-truthing tools to the management of cold-water coral ecosystems represents a critical step forward in our ability to identify and protect these valuable
ecosystems.
Acknowledgments The authors thank NOAA Oceans Explorer program for AUV ship time, as
well as C&C Technologies, the crew of the R/V Northern Resolution, R/V Seward Johnson, and
the JSL-II submersible. A grant provided by the State of Florida, Medicines from Florida’s
Oceans Project (HBOI Project # S2156, S2168) provided funding for the submersible cruises. We
also thank David Viggiano for current data processing, and John K. Reed for his input on the
manuscript. Post-cruise analyses are supported by the American Chemical Society Petroleum
Research Fund (#49017ND8) and by the Industrial Associates of the Comparative Sedimentology
Laboratory (CSL) at the University of Miami.
10 Deep Acoustic Applications
279