Coral Reef Habitat Monitoring Ecosystem based management requires multifaceted monitoring Habitat = benthos + water column Coral reef ecosystems ≈ 0 – 100 m Logistical challenges increase at depths >30 m; mapping vs. monitoring Corals, macroalgae, etc. both utilize and provide habitat French Frigate Shoals, photo by Jean Kenyon

Why bother to monitor coral reef habitats? ● CREs (coral reef ecosystems) are both important resources and dynamic ecosystems. Need understanding of temporal variability to interpret and respond to future changes. ● Knowledge of habitats required for effective implementation of spatially-based management, e.g., MPAs. ● Legal mandates – e.g. E.O ; consistent with findings of the MSFCMA, “Habitat considerations should receive increased attention...” ● Need better management locally and regionally to reduce stressors, thereby increasing CRE resilience to Global scale problems, e.g., warming, ocean acidification, etc. ● Habitat monitoring to identify problems, including bleaching events, marine debris, invasive species, etc., improves our ability to respond to these threats and better manage Hawaiian CREs. The more we know the better able we are to manage Hawaiian coral reef ecosystems.

Why bother to monitor coral reef habitats? How Monitor? ● Water column (in situ instrumentation) ● Habitats < 30 m deep (benthic towboarding) ● Habitats 30 – 100+ m deep (multibeam and optical mapping) Results: ● Statistics: towboarding multibeam surveying optical surveying ● Pearl and Hermes Atoll thermocline - multidisciplinary results Future Directions: ● Benthic shear stress modeling – Hanalei Bay ● m multibeam surveying, MHI ● Hard/soft benthic substrate classification ● Mesophotic coral reefs in the Auau Channel ● Seabed AUV Ecosystem based science and management requires in situ multidisciplinary research.

MHINWHITotal No. Tows Total Length (km)5871,1801,767 Mean Tow Length (km) Benthic Towboarding ● Meso-scale monitoring ● >135 tracks total ● reoccupied ~biennially ● Observer data – 5 min. integrations ● Archival photos, 15 sec. ● Limitations

30 kHz EM m range 135 beams R/V AHI NOAA Ship Hi’ialakai 240 kHz Reson 8101ER 250 m range 101 beams 30 kHz EM m range 135 beams 300 kHz EM3002D 150 m range “soundings”

Survey Days Remaining Area Surveyed (km 2 ) % Completed (<200 m) MHI~302,67095 NWHI~24045,52030 Multibeam Data ● Hi-res. Bathymetry ● Rugosity, etc. ● Backscatter imagery

Still Photos VideosKilometers Surveyed MHI032~64 NWHI ~452

Satellite SST data: - resolution too coarse - no surface expression

Preliminary Results: Estimation of Mechanical Dislodgement Threshold Breakage occurs when “Colony Shape Factor (CSF)” exceeds DMT (Madin and Connelly, 2006) Patterns in benthic communities at a remote subtropical atoll along a wave exposure gradient (Page-Albins et al., submitted) (Images courtesy of Ronald Hoeke)

Max Depth2000 m Endurance8 hours Speed1.0 kt optimal, (0.4 to 2.0) Weight300 kg Depth trackingAltitude or depth Cameras4-Mpixel 12-bit w/strobes Navigation1200kHz Doppler Velocity Log and Fiberoptic IMU