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Habitat Suitability Modeling for Deep-Sea Corals off the U.S. West Coast

Project Goal

Predict the potential distribution of deep-sea corals off the U.S. West Coast in order to better target future field research and conservation action.

Geographic Location

U.S. West Coast – U.S. waters off Washington, Oregon & California


The deeper waters off the U.S. Pacific Coast are known to host rich deep-sea coral habitats, but the vast majority of this region remains unexplored. Under a contract from NOAA, Drs. John Guinotte and Andrew Davies developed predictive habitat models that combine location data where corals have been documented with information on their surroundings (physical, chemical and environmental variables). This approach provides information on the corals’ environmental niches and allows us to identify areas with similar conditions in unsurveyed areas.


The models identified slope, temperature, salinity and depth as important predictors for where different groups of deep-sea corals are likely to occur. Some areas that appear to be highly suitable for deep-sea coral habitat are predicted to lie within the boundaries of NOAA’s national marine sanctuaries or in areas already protected from bottom trawling. Other predicted areas remain unprotected. Predicted habitat suitability results cannot identify deep-sea coral areas with pin-point accuracy and probably over-predict actual coral distributions due to unincorporated variables (e.g. substrate). However, when used in conjunction with multibeam bathymetry and other tools, the models can help guide future research efforts to areas with the highest probability of harboring deep-sea corals. NOAA will be using these models to help plan the third year of the Deep Sea Coral Research and Technology Program’s field research off the West Coast in 2012. These efforts in turn will allow field validation and refinement of the models.

Importance to Management

The first requirement for managing human impacts to deep-sea corals is to know where these habitats are located. This project provides the first comprehensive predictions on where deep-sea corals are likely to occur off the U.S. West Coast. These models can help managers avoid interactions between fisheries or other human activities and sensitive deep-sea coral habitats when used in conjunction with other information, such as coral bycatch reports from fisheries and NOAA’s research trawl surveys., The results of this project are being provided to the 5 year review of the Pacific Fishery Management Council’s essential fish habitat (EFH) actions.


Guinotte, JM and Davies, AJ (in review). Predicted deep-sea coral habitat suitability for the U.S. West Coast. Report to NOAA

Fiscal Year 2010 Funding


Point of Contact

Thomas F. Hourigan, Tom.Hourigan@noaa.gov

Predicted habitat suitability off Washington and Oregon for two important groups of deep-sea corals: a) gorgonian deep-sea corals (Suborder Holaxonia); and b) black corals (Order Antipatharia). The figures show the boundaries of Olympic Coast National Marine Sanctuary (in white) and areas where bottom trawling was prohibited in 2006 to conserve essential fish habitat (cross-hatched Habitat areas of Particular Concern, and stippled zones). Areas where three or four models predict coral habitat are shown in orange and red. Most black corals are predicted to occur in deeper waters where trawling is not allowed. In contrast, most holaxonian gorgonians are predicted to occur in intermediate depth waters that may be open to fishing using bottom trawls.

Credit: Guinotte and Davies (in review)