Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Skip to content

Observed Presence of Alien and Invasive Algae, 2000-2013 - Hawaii

Metadata Updated: June 3, 2023

Due to the geographic isolation of the Hawaiian Islands, close to 25% of Hawaii's reef fishes and red algae species are endemic. This leaves Hawaiian coral reefs particularly vulnerable to alien invasions due to their valuable role as a biodiversity resource. Invasive algae can pose a serious threat to coral reefs by spreading and growing rapidly, smothering or outcompeting corals and other organisms. This can significantly alter the structure and function of the reef ecosystem. Four species of alien red algae have become invasive in Hawaii: prickly seaweed (Acanthophora spicifera), hookweed (Hypnea musciformis), smothering seaweed (Kappaphycus spp.), and gorilla ogo (Gracilaria salicornia). This raster data layer represents the presence of alien and invasive algal species within 1 km of an observation. Invasive algae data originated from monitoring surveys in the University of Hawaii at Manoa (UH) Fisheries Ecology Research Laboratory (FERL) Hawaii Fish and Benthic Biological Synthesis Database (2000-2013), which is synthesized from NOAA, State of Hawaii Division of Aquatic Resources (DAR), Coral Reef Assessment and Monitoring Program (CRAMP), and The Nature Conservancy (TNC), as well as invasive algae surveys conducted across the state in 2002 by Dr. Jennifer Smith (Smith et al., 2002).

These data should be considered presence only. Areas with no presence may be due to lack of survey data, surveys that did not identify algae to the species level, or observed absence. Point data for transects with observed presence of any invasive algae were assigned a value of 1 and converted to raster with 500-m pixel size. To account for uncertainty in geographic position and the fragmentation and spread of algae, the Ocean Tipping Points (OTP) project estimated presence within a 1-km radius of observed invasive algae presence. A Focal Statistics tool was run to calculate the maximum value within a 1-km radius of each pixel with the assumption that if an invasive algae was observed in one location it is likely present in at least the surrounding 1 km of reef area. Final raster values of 1 represent areas within 1 km of positive invasive algae observations while values of 0 represent the remaining area. The geographic extent of the data layer is from the shoreline of the Main Hawaiian Islands extending 5 km offshore and 1 km inshore.

Access & Use Information

License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources


Metadata Date March 30, 2021
Metadata Created Date November 12, 2020
Metadata Updated Date June 3, 2023
Reference Date(s) March 14, 2017 (creation), March 14, 2017 (issued), March 14, 2017 (revision)
Frequency Of Update

Metadata Source

Harvested from ioos

Graphic Preview

Sample image.

Additional Metadata

Resource Type Dataset
Metadata Date March 30, 2021
Metadata Created Date November 12, 2020
Metadata Updated Date June 3, 2023
Reference Date(s) March 14, 2017 (creation), March 14, 2017 (issued), March 14, 2017 (revision)
Responsible Party National Center for Ecological Analysis and Synthesis (NCEAS) (Point of Contact)
Contact Email
Guid hi_otp_all_invasive_algae
Access Constraints
Bbox East Long -154.67768920003857
Bbox North Lat 22.27916178151476
Bbox South Lat 18.84863823350594
Bbox West Long -160.29941254176182
Coupled Resource [{"title": [], "href": ["#DataIdentification"], "uuid": []}, {"title": [], "href": ["#DataIdentification"], "uuid": []}, {"title": [], "href": ["#DataIdentification"], "uuid": []}]
Frequency Of Update
Graphic Preview Description Sample image.
Graphic Preview File
Harvest Object Id bb7ce826-227e-4848-9029-4d081853fa3f
Harvest Source Id 54e15a6e-6dde-4c9c-a8f0-345cc0dfccfb
Harvest Source Title ioos
Lineage 2017-03-14T00:00:00Z OGC web services (WMS and WFS) enabled by PacIOOS via GeoServer. Original data from source provider may have been reformatted, reprojected, or adjusted in other ways to optimize these capabilities.
Metadata Language eng
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-160.29941254176182, 18.84863823350594], [-154.67768920003857, 18.84863823350594], [-154.67768920003857, 22.27916178151476], [-160.29941254176182, 22.27916178151476], [-160.29941254176182, 18.84863823350594]]]}
Spatial Data Service Type Open Geospatial Consortium Web Coverage Service (WCS)
Spatial Reference System
Spatial Harvester True

Didn't find what you're looking for? Suggest a dataset here.