Five-minute grid shapefile with marine bird density data off central California, CDAS data (1980-2001)

A shapefile of five minute grids that contains marine bird density data at-sea from the CDAS Central CA data set (1980-2001). It is a shapefile representing 5 minute x 5 minute latitude x longitude cells that house the densities (birds/sq.km.) of 40 species of marine birds during the Upwelling, Oceanic and Davidson Current Seasons. The number of marine birds seen in a cell was divided by the area sampled in the cell to estimate density. If a cell was surveyed more than once, densities were averaged and weighted according to effort. Cells that were surveyed but in which no birds were observed have densities of zero.

This shapefile was used to map bird density maps for NOAA from the CDAS data set.

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The CDAS data set (1980-2001) was developed and is maintained by R.G. Ford Consulting Co. It is a combination/ synthesis of at-sea data sets off the U.S. west coast of CA,OR and WA. This shapefile was created as part of a biogeographic assessment of marine resources off northern and central California, for the National Oceanic and Atmospheric Administration's Ocean Service. For additional information, see the bird chapter of the Phase 2 report at http://ccma.nos.noaa.gov/ecosystems/sanctuaries/california/html/birds/. For additional information on the aerial survey data, see CD-ROM, Marine Mammal and Seabird Computer Database Analysis System, Washington, Oregon, and California (1975-1997). For additional ship-based survey data information, contact the following contributing researchers: SF-DODS Cruises (1996-2000) EPOCS Cruises (1984-1994) David G. Ainley, Ph.D. H.T. Harvey and Associates 3150 Almaden Expressway, Suite 145 San Jose, California 95118 dainley@sbcglobal.net Midwater Trawls for Juvenile Rockfish(1985-2001) David G. Ainley, Ph.D. (see above) and Carol Keiper, Ph.D. Oikonos P.O. Box 979 Bolinas, Calfornia 94924 carol@oikonos.org ORCAWALE Cruise (2001) Lisa T. Ballance, Ph.D. Ecosystem Studies Program Southwest Fisheries Science Center 8604 La Jolla Shores Drive La Jolla, California 92037 lisa.ballance@noaa.gov

Thus file contains at-sea summary distributional data for seabirds off north/central CA, from 1980-2001. The data is summarized into 5-minute grids.

For explanations of the attributes, please see the excel file on the Data DVD called DefinitionsofCDASBirdAcronyms.xls

These data were prepared for 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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This data set is in the public domain, and the recipient may not assert any proprietary rights thereto nor represent it to anyone as other than a data set compiled by R. G. Ford Consulting Company for the National Oceanic and Atmospheric Administration's National Ocean Service.

This data set is provided "as-is" without warranty of any kind. The user assumes all responsibility for the accuracy and suitability of this data set for a particular purpose.

Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.0.1324

The at-sea density data, from which this shapefile was created, are the result of a synthesis of data from eight shipboard and aerial survey programs conducted in the study area in the years 1980-2001. Observation and trackline data from these studies were converted to a common format. All aerial data were continuous; ship-based data were converted separately into a continuous transect to the extent possible. From the digitized survey data, the distributions of effort and of marine bird species were mapped into 5 minute latitude x 5 minute longitude cells using CDAS, a custom geographic information system for analyzing marine bird and mammal surveys (MMS-CDAS 2001). The length and width of the survey trackline in a given cell (estimated trackline width varied by platform, depending on speed and height above water) were used to estimate the area sampled. The number of marine birds seen in a cell was then divided by the area sampled in the cell to estimate density. If a cell was censused more than once, densities were averaged, with adjustment made for effort. Although the at-sea data span the years 1980-2001, data are not available for all seasons in all years. For the Upwelling Season, data are from 1980-1982 and 1985-2001. For the Oceanic Season, data are from 1980-1982, 1991 and 1994-2001. For the Davidson Current Season, data are from 1980-1986 and 1991-2001. All data sources were thoroughly checked for accuracy, consistency and completeness. Accuracy analyses were not applicable to this data set and therefore not produced.

All shapefile cells have attribute information.

All shapefile attributes were checked for consistency of appropriate range values.