Seagrass distribution off California

These data are a compilation of currently available seagrass GIS data sets for the west coast of the United States. These data have been compiled from seventeen different data sources. The source data were acquired over a large range of time periods, at many different spatial resolutions using a variety of methods, including aerial photography, videography, multispectral sensors, sonar, and field surveys. Users are cautioned to use these data as only a regional view of seagrass locations. Areas without mapped seagrass may contain seagrass, but digital data were unavailable during this data compilation

These data were developed for Pacific States Marine Fisheries Commission in cooperation with the National Marine Fisheries Service Northwest Region and the Pacific Fishery Management Council in support of an Environmental Impact Statement (EIS) to consider the designation and conservation of Essential Fish Habitat (EFH) for Pacific Coast Groundfish. These data were consolidated and integrated in a GIS format to support spatially explicit groundfish habitat modelling and impacts assessment on a coastwide scale.For this project, these data were used to examine the spatial distribution of seagrasses in context with a comprehensive biogeographic analysis of natural resources within southern California.

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Users are cautioned to use these data as only a regional view of seagrass locations. Areas without mapped seagrass may contain seagrass, but digital data were unavailable during this data compilation.

These data were prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data have been used by NOAA, no warranty, expressed or implied, is made by NOAA as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by NOAA in the use of these data or related materials.

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Before using the data for Morro Bay,California, users must contact Morro Bay National Estuary Program at 805-772-3834.

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535

Attributes for source data sets were not validated. A quick visual review of merged data set was performed to assure that merging functions correctly retained attributes from source data.

Horizontal positional accuracy was not assessed. Positional accuracy is dependent upon each of the source data sets.

These data are by no means comprehensive for the entire West Coast. The data are generally more concentrated in populated areas that have been the focus of eelgrass studies and mapping project. Eelgrass areas have been the subject of many mapping projects, however surfgrass has only been mapped in a couple projects. Because a comprehensive coastwide survey has not been conducted for seagrass, it is difficult to know where the data gaps are.

Data are compiled from seventeen different data sources. These source data were created using a large variety of technologies, including aerial photography, underwater videography, aerial videography, aerial multispectral sensors, sonars (single beam, multibeam, and side-scan) and field surveys. Along with the multitude of data collection technologies, there were a multitude of spatial resolutions, georeferencing accuracies, and verification techniques.