Climate change threatens even the best-protected and most remote reefs. Reef recovery following catastrophic disturbance usually requires disturbed sites be reseeded from upstream reefs. Recent research (McClanahan et al., 2012) assessed connectivity as an important resilience factor, which although difficult to measure, is a high priority for management of coral reef ecosystems. The products described herein identify reefs that act as “sources” and/or “sinks” in the Hawaiian Archipelago (and Johnston Atoll) to inform reef management strategies. Tools developed provide information on connectivity among reefs, thereby advancing the capacity for reef connectivity assessment.
Connectivity among coral reefs has been identified as a critically important factor in resilience, specifically in regard to recovery from disturbance. The products described herein include maps identifying the level of importance of specific reefs in terms of the potential for reseeding other reefs following disturbance. The product format is compatible with other components being developed in the emergent resilience framework. This will directly contribute to new and ongoing resilience assessments and planning of Marine Protected Areas (MPAs), MPA networks, and other conservation strategies.
The Larval Connectivity products and data mentioned in this metadata file are accessible at: https://coralreefwatch.noaa.gov/product/larval_connectivity/index.php.
ground condition
Not intended for legal use. Data may contain inaccuracies.
NOAA Center for Weather and Climate Prediction (NCWCP), E/RA3, 5830 University Research Court, 3rd Floor, Room 3222
https://coralreefwatch.noaa.gov/product/larval_connectivity/fig/MHI_source_60_days.jpg
The accuracy of the Larval Connectivity metrics depends on the accuracy of the modeled ocean currents used for deriving the product. HYbrid Ocean Coordinate Model (HYCOM) output at 2/25 degree (~9 km) resolution was employed to simulate the virtual particle tracks across the domain. The HYCOM system incorporates surface forcing (wind stress, wind speed, heat flux and precipitation) and assimilates satellite and in situ data (sea surface height, sea surface temperature, vertical profiles of temperature and salinity). For further details and references of the model system, see http://hycom.org/data/glbu0pt08/expt-19pt0 and http://hycom.org/data/glbu0pt08/expt-19pt1.
Modeled currents were applied as best-available estimates of ocean currents without verification against any observations. Where model output was unavailable (see http://hycom.org/faqs/463-nrl-netcdf-outputs-missing-days), gaps were filled by interpolating the anomaly of each current component (east, north) through the missing-data period.
This is the first release of this product. Because this is currently an experimental product undergoing research and development, revisions to the product may occur.
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The Larval Connectivity products were derived from this ocean currents product. The 1/12 degree global HYCOM+NCODA Ocean Reanalysis was funded by the U.S. Navy and the Modeling and Simulation Coordination Office. Computer time was made available by the DoD High Performance Computing Modernization Program. The output is publicly available at http://hycom.org.
Known reef locations were gridded onto a 1/25 degree (~4 km) grid, and virtual particles representing coral larvae were positioned across each reef cell. Movement for each particle was determined by interpolating daily HYCOM ocean currents output (at 2/25 degree resolution) to the location of the particle. When no model output was available for a day, temporal gapfilling was performed, resulting in no remaining gaps. Particle intersections with reef locations were recorded to indicate potential connectivity between each pair of source and destination reefs. The relative importance of reef locations, as a source and as a destination for larvae, was determined by accumulating the frequency of identified connections. Results were summarized for several maximum pelagic larval durations and seasonal larval release. See CRW website at: https://coralreefwatch.noaa.gov/product/larval_connectivity/index.php for details.
These are the image display of Larval Connectivity product data.
https://coralreefwatch.noaa.gov/product/larval_connectivity/index.php
NOAA makes no warranty regarding these data and images, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these images, nor as a result of the failure of these data to function on a particular system.
Larval Connectivity webpage
Larval Connectivity output files
The product in various formats may be downloaded from the website or obtained directly from the distributor.
