1. Marine Habitat Mapping, Applications for Fisheries Management
Jens Kruger
SPC’s Division of Applied Science and Technology
CEAFM workshop, December 2010

2. Why map benthic habitats?
Seafloor habitat mapping provides fundamental baseline information for decision-makers working in all sectors:
Fisheries assessments
Environmental impact statements
Decision to approve extractive/other use
State of Environment reporting (inventory of assets)
Design of marine reserves

3. Uses of habitat maps (under different guises)
Fisheries (fish habitat for stock assessment)
Navigation (reef, sandbank, bank, shoal etc.)
Aggregate extraction (resource assessment)
Deep sea minerals lease assessment
Ports and harbours (channels, intertidal, shoals)
Infrastructure (cables, pipelines, etc.)
Defence (mine countermeasures, acoustics)
Spatial management (eg. MPAs)

4. What is a habitat map?
Map of the biophysical environment that shows where particular benthic species or communities occur (or are likely to occur)
Based on geomorphology, oceanography, primary production, depth, sediment type, seafloor roughness, etc.
Habitat maps can be derived from any one or all of these variables WITH information on benthic communities

5. Aitutaki, Cook Islands Impacts of coastal development on the lagoon ecosystem
CHANNEL
Proposed capital dredging:
Attract yacht tourism ($60,000/year)
Deepen & widen shipping channel for navigation
Improve port facilities
Baseline Data Needs:
Marine Habitats
Bathymetry
Hydrodynamics 5

6. Methods: Habitat Mapping
GPS
GPS towed by diver with camera
camera
GPS
line
Currently no building standards based on local seismic risk
camera
slate
drybag
floats &
weight

7. Methods: Bathymetry and Oceanography
Satellite
imagery
multibeam echosounder
Current Meter
Multibeam
RTK
GPS
MBES
Tide
Gauge
Singlebeam
GPS
In shallow lagoon can cover 50km^2 / day for $10000 / day but inefficient and dangerous in areas less than 15m
LIDAR can survey 100km^2 a day for $ / day
SBES
rim
reef
fringing
reef
lagoon
NEARSHORE

8. Marine Habitat Map of Aitutaki, … as well as bathymetry and computer model
Bathymetry Map
Numerical Hydrodynamic Model

9. Bathymetry Map of Majuro Atoll

10. Majuro Lagoon Backscatter Mosaic

11. Potential Habitat Map of Majuro Lagoon (no ground truthing & not detailed)
HABITAT TYPE MAP
From bathymetry and backscatter data the following map was produced.
Most of the area is covered by the karst type of habitat while the deeper parts of the lagoon shows flat fine to medium sand.
The entrance channel is dominant with the sediment covered outcrops and subcrops.
Now we will look in a little detail of one of the seismic lines and backscatter that cuts across three different habitat types.
Sediment covered outcrops/subcrops
Flat fine to medium sand
Sediment aprons
Land
Areas dominated with Halimeda mounds
Coral heads

12. Bathymetry Mapping
Official Marine Chart of Niutao, Tuvalu

13. Bathymetry Map of Efate, Vanuatu
20 years of ship sounding data were merged with high-resolution nearshore multibeam data to compile a 50 m Digital Terrain Model
Data Sources
DTM of Efate

14. Bathymetry of Efate, Vanuatu
3D perspective view of Efate. 4x vertical exaggeration

15. Bathymetry Map of Samoa
3D perspective view of Upolu and Savai’i

16. Growing Map and Spatial Data Repository http://geonetwork.sopac.org
2011: Marine surveys in Tongatapu, TO; Mangaia, CK; Rangiroa, FP

17. Application to Fisheries Management
Bonefish Fishery Management Plan for Aitutaki
Catch and Release Fishing in Aitutaki: Sport Fishing Workshop June, SPC & MMR
Bathymetry and habitat maps used to identify areas suitable for bonefish fly-fishing
Fish Aggregation Devices
Focus on food-security & climate change adaptation
Recent deployments in Kiribati, Samoa, Marshall Islands, Nauru
Planned deployments in Solomon Islands and Tuvalu

18. Marine Habitat Mapping and Numerical Modelling an underutilised tool for fisheries and marine ecosystem management in PICTs
Funafuti, Tuvalu. Data holdings include bathymetry, water elevation, wave and current velocities, seismic subbottom profiles, sediment samples, satellite imagery, computer model, etc. , etc.
Collective wealth of information forms the basis for management tools
Previously limited understanding