Marine Habitat Mapping, Applications for Fisheries Management
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Transcript of Marine Habitat Mapping, Applications for Fisheries Management
Marine Habitat Mapping,Applications for Fisheries
Management
Jens KrugerSPC’s Division of Applied Science and Technology
CEAFM workshop, December 2010
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
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 assessmentPorts and harbours (channels, intertidal, shoals)Infrastructure (cables, pipelines, etc.)Defence (mine countermeasures, acoustics)Spatial management (eg. MPAs)
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
Aitutaki, Cook IslandsImpacts of coastal development on the lagoon ecosystem
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
CHANNEL
Methods: Habitat Mapping
GPS
camera
drybag
GPS
slate
floats &weight
camera
line
GPS towed by diver with camera
Methods: Bathymetry and Oceanography
NEARSHORE
rimreef
lagoonfringing
reef
TideGauge
Satelliteimagery
MBES
SBES
RTKGPS
multibeam echosounderMultibeamCurrent Meter
Singlebeam GPS
Marine Habitat Map of Aitutaki, … as well as bathymetry and computer model
Bathymetry Map
Numerical Hydrodynamic Model
Bathymetry Map of Majuro Atoll
Majuro Lagoon Backscatter Mosaic
Potential Habitat Map of Majuro Lagoon(no ground truthing & not detailed)
Land
Areas dominated with Halimeda mounds
Coral heads
Sediment covered outcrops/subcrops
Flat fine to medium sand
Sediment aprons
Bathymetry Mapping
Official Marine Chart of Niutao, Tuvalu
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
DTM of Efate Data Sources
Bathymetry of Efate, Vanuatu
3D perspective view of Efate. 4x vertical exaggeration
Bathymetry Map of Samoa
3D perspective view of Upolu and Savai’i
Growing Map and Spatial Data Repositoryhttp://geonetwork.sopac.org
2011: Marine surveys in Tongatapu, TO; Mangaia, CK; Rangiroa, FP
Application to Fisheries Management
Bonefish Fishery Management Plan for Aitutaki
• Catch and Release Fishing in Aitutaki: Sport Fishing Workshop 16-23 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
Marine Habitat Mapping and Numerical Modellingan 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.
Previously limited understanding Collective wealth of information forms
the basis for management tools