Habitat use by juvenile Dungeness crabs in coastal nursery estuaries

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Frequently-anticipated questions:

What does this data set describe?

Title:
Habitat use by juvenile Dungeness crabs in coastal nursery estuaries
Abstract:
Juvenile Dungeness crabs are found extensively throughout U.S. West Coast estuaries. Trawl surveys targeting juvenile Dungeness crabs were conducted in the summers of 1998-2000 in four West Coast estuaries: Coos Bay and Yaquina Bay, Oregon, and Grays Harbor and Willapa Bay, Washington. Additional data from surveys in Willapa Bay (1985-1988) and Grays Harbor (1983-1988) were also utilized in this study. Densities of age 0+ and age 1+ juvenile crabs were analyzed using analysis of variance techniques for each of the four estuaries. Patterns of crab density in each of the four estuarine systems suggest they prefer lower side channel sites close to the estuary mouth. Our trawl survey data indicate that crabs utilize these subregions of estuaries which are characterized by borad intertidal flats with extensive secondary subtial channels. These subregions are further characterized by abundant local refuge (shell, macroalgae), high prey abundance, shallow depths, temperatures less than 18ºC, and relatively high salinities. Significant interannual variation was evident for both age classes. Mean density of age 0+ crabs varied by a factor of 54 over the years studies, while mean density varied only by a factor of 7 for age 1+ crabs.
Supplemental_Information:
Data included in usSEABED are sediment collected in support of this study. Data given to Mark Zimmermann, NOAA, from Chris Rooper, UW, 2002. Data digitized by the USGS for inclusion into usSEABED (<http://walrus.wr.usgs.gov/usseabed>)
  1. How should this data set be cited?

    Rooper, Christopher N. , Armstrong, David A. , and Gunderson, Donald R. , 2002, Habitat use by juvenile Dungeness crabs in coastal nursery estuaries: Crabs in Cold Water Regions: Biology, Management, and Economics Alaska Sea Grant Program, AK-SG-02-01, Pg. 609-629, Alaska Sea Grant College Program, Seattle, WA.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -125.34500
    East_Bounding_Coordinate: -123.90300
    North_Bounding_Coordinate: 47.00700
    South_Bounding_Coordinate: 43.31864

  3. What does it look like?

    Rooper_2002 (JPG)
    Screen grab of GIS-produced sample distribution, with bathymetry and land for reference.

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 1983
    Ending_Date: 2000
    Currentness_Reference: Publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: Digital

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Point (69)

    2. What coordinate system is used to represent geographic features?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.01667. Longitudes are given to the nearest 0.01667. Latitude and longitude values are specified in Decimal degrees.

  7. How does the data set describe geographic features?

    Point
    SDTS point (Source: Source datafile)

    Sample number
    Sample number (Source: Source datafile)

    Alpha numeric number based on physiographic location and core information

    Sieve size analysis
    Weight percent of sample caught in given sieve. (Source: Source report)

    Range of values
    Minimum:>-1 phi
    Maximum:< 4 phi
    Units:Percent
    Resolution:0.01

    Shell
    Shell percentage in given sieve size (Source: Source datafile)

    Range of values
    Minimum:50
    Maximum:100
    Units:Percent
    Resolution:1.0

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Rooper; C.N.; Armstrong; D.A.; and Gunderson; D. at the Alaska Sea Grant Program for the collection, analysis, and compilation of data; Mark Zimmermann (NOAA) for facilitation of data donation to usSEABED, usSEABED formatting and corrections Jane Reid (USGS) and Chris Jenkins (University of Colorado).

  3. To whom should users address questions about the data?

    University of Washington
    P.O. Box 357940
    Seattle, WA 98195

    206-543-5060 (voice)

Why was the data set created?

This study assesses the habitat use by juvenile Dungeness crabs using data collected from trawl surveys of coastal estuaries. The objective of these surveys was to determine consistent patterns in spatial use of nursery habitat across four estuaries and a number of years. Additionally, the density of juvenile Dungeness crabs was compared to the dominant habitat features associated with their spatial locations.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 1998 (process 1 of 1)
    "In 1998 a benthic grab was used to collect a sediment sample at each site. In the laboratory a subsample of approximately 100 g was removed for analysis. Hydrogen peroxide was used to remove organicmaterial, and the sample was then dried for 2-4 hours. The sample was weighed, placed on a stack of sieves ranging in size from 1 mm to 0.62 microns, and shaken using a Ro-Tap machine for 15 minutes. The resulting components of the sample in each sieve size were weighed."

    Person who carried out this activity:

    University of Washington
    P.O. Box 357940
    Seattle, WA 98195

    206-543-5060 (voice)

    Data sources produced in this process:
    • Rooper_et_al_2002

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    No estimate made for the accuracy of the data in the original report. Data digitized by the USGS and partners were visually compared to the source data, and corrected. Where appropriate, data were tested for completeness using MS Excel. Locations checked using GIS.

  2. How accurate are the geographic locations?

    Navigation by GPS. Latitudes and longitudes as decimal degrees.

  3. How accurate are the heights or depths?

    Water depth not included in data file.

  4. Where are the gaps in the data? What is missing?

    All data provided by authors included in usSEABED.

  5. How consistent are the relationships among the observations, including topology?

    Data fall within normal ranges for the given parameters.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_Constraints:
Cite Christopher N. Rooper, David A. Armstrong, Donald R. Gunderson, and the University of Washington as originators of the data.

  1. Who distributes the data set? (Distributor 1 of 1)

    University of Washington
    P.O. Box 357940
    Seattle, WA 98195

    206-543-5060 (voice)

  2. What's the catalog number I need to order this data set?

    Sediment data collected in support of "Crabs in Cold Water Regions: Biology, Management, and Economics; Alaska Sea Grant College Program, AK-SG-02-01"

  3. What legal disclaimers am I supposed to read?

    Although this dataset has been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data. Users of the data should be aware of limitations of the data due to possible imprecision due to navigational inaccuracies and limitations of the sampling data.

  4. How can I download or order the data?

  5. What hardware or software do I need in order to use the data set?

    None

Who wrote the metadata?

Dates:
Last modified: 2005
Metadata author:
U.S. Geological Survey
c/o Jane A. Reid
Geologist
400 Natural Bridges Drive
Santa Cruz, CA 95060

831-427-4727 (voice)
jareid@usgs.gov

Contact_Instructions: Email preferred
Metadata standard:
CSDGM Version 2 (FGDC-STD-001-1998)

Generated by mp version 2.8.17 on Sat May 20 21:53:20 2006