Description
This dataset contains shell lengths and lip thicknesses of queen conch individuals located and measured while conducting radial surveys of the conch populations on the northern shelf of St. Croix. The date, location, water depth, and general benthic habitat description were measured and described at each radial survey site (see InPort record number 30680 for specific project metadata).
Resources
| Name | Format | Description | Link |
|---|---|---|---|
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| FTP | Unknown | These data are available through the File Transfer Protocol (FTP). FTP is no longer supported by most internet browsers. You may copy and paste the FTP link to the data into an FTP client (e.g., FileZilla or WinSCP). | |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2023. GCMD Keywords, Version 16. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2023. GCMD Keywords, Version 16. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2025. GCMD Keywords, Version 21. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2023. GCMD Keywords, Version 16. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| GCMD Keyword Forum Page | Unknown | Global Change Master Directory (GCMD). 2023. GCMD Keywords, Version 16. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| https://www.fisheries.noaa.gov/inport/item/30680 | Unknown | InPort Metadata Record | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Dataset Landing Page | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| HTTPS | Unknown | Navigate directly to the URL for data access and direct download. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| Descriptive Information | Unknown | Navigate directly to the URL for a descriptive web page with download links. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NCEI Contact Information | Unknown | Information for contacts at NCEI. | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
| US DOC; NOAA; NMFS; Southeast Fisheries Science Center website | Unknown | Institution web page | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
| NOAA Southeast Fisheries Science Center (NMFS/SEFSC) website | Unknown | Institution web page | Open resource |
Tags
- 1100
- 72wax3
- assessing performance and connectivity of st. croix mpas
- atlantic ocean
- biology
- buck island (17n064w0006)
- buck island reef (17n064w0001)
- caribbean sea
- census
- country/territory
- earth science
- macroinvertebrate communities
- macroinvertebrates
- marine biology
- marine invertebrates
- north atlantic ocean
- numeric data sets
- ocean basin
- oceanography
- oceans
- population density
- salt river bay (17n064w0022)
- shell parameters (length or lip thickness)
- st. croix
- st. croix (17n064w0003)
- united states of america
- u. s. virgin islands
- virgin islands