Transcript Day 03 02 Marine habitat mapping

Marine Habitat Mapping,
Applications for Fisheries
Management
Jens Kruger
SPC’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 assessment
Ports 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 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
Methods: Habitat Mapping
GPS
GPS towed by
diver with
camera
camera
GPS
line
camera
drybag
floats &
weight
slate
Methods: Bathymetry and Oceanography
Satellite
imagery
multibeam echosounder
Multibeam
Current Meter
MBES
Singlebeam
RTK
GPS
GPS
SBES
rim
reef
lagoon
NEARSHORE
Tide
Gauge
fringing
reef
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
Sediment covered outcrops/subcrops
Areas dominated with Halimeda mounds
Flat fine to medium sand
Coral heads
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
Data Sources
DTM of Efate
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 Repository
http://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 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.
Previously limited understanding
Collective wealth of information forms
the basis for management tools