Variables in this Dataset

OBSERVER_TRAWL_2002_2006: Sequence
SYS_ID: 64 bit Real
  • Description: "Unique system identifier."
GRID_ID: 64 bit Real
  • Description: "Unique grid cell identifier."
LAT10KM: 64 bit Real
  • Description: "Latitude of the center of a 10 km x 10 km grid cell."
LONG10KM: 64 bit Real
  • Description: "Longitude of the center of a 10 km x 10 km grid cell."
FISHERY: String
  • Description: "Groundfish fishery sector by permit and gear-type."
SURVEY_YEARS: String
  • Description: "Time period of combined data: 2002-2006."
SCIENTIFIC_NAME: String
  • Description: "The scientific name used to identify a species."
COMMON_NAME: String
  • Description: "The common name used to identify a species."
DISCARD_RATE: 64 bit Real
  • Description: "Discard rate calculated as the species discard weight divided by the total catch (discard + retained) weight of groundfish in the 10 km x 10 km grid cell."


Observer Trawl Data collected during 2002-2006 off West Coast of US

Observer Trawl Data collected during 2002-2006 off West Coast of US

 

This data product originates from data collected by fishery observers in the West Coast Groundfish Observer Program (WCGOP), Fishery Resource Analysis and Monitoring Division (FRAM) at the Northwest Fisheries Science Center, NOAA Fisheries.  The WCGOP's goal is to improve total catch estimates by collecting information on the discarded catch (fish returned overboard at-sea) of west coast groundfish species.  All data were collected according to standard protocols and data quality control established by the WCGOP.  The observed portion of overall catch or landings in a fishery varies by coverage level.  Since all fishing operations are not observed, neither the maps nor the data can be used to characterize the fishery completely.  This is especially true for rarely-occurring species and when observed sample sizes are small.  We urge caution when utilizing these data due to the complexity of groundfish management and fleet harvest dynamics.  Grid cells representing less than 3 vessels and less than 10 hauls or sets are not shown due to confidentiality and to ensure adequate sample size.  In the limited-entry groundfish bottom trawl fishery, species discard rates (species discard weight / groundfish total catch (discard + retained weight)) are categorized by approximate quartile ranges and geo-referenced to 10 x 10 kilometer grid cells.  The observed trawl towline (line drawn from the start to end location of a trawl tow) was used to allocate data to 10 x 10 kilometer grid cells for calculation.  Seventeen species were represented based on combined observer data from 2002-2006.  The species included in this data product are dover sole (Microstomus pacificus), sablefish (Anoplopoma fimbria), longspine thornyhead (Sebastolobus altivelis), shortspine thornyhead (Sebastolobus alascanus), lingcod (Ophiodon elongatus), arrowtooth flounder (Atheresthes stomias), English sole (Parophrys vetulus), petrale sole (Eopsetta jordani), and the rockfishes (genus Sebastes), darkblotched rockfish (S. crameri), Pacific ocean perch (S. alutus), chilipepper (S. goodei), cowcod (S. levis), bocaccio (S. paucispinis), canary rockfish (S. pinniger), widow rockfish (S. entomelas), yelloweye rockfish (S. ruberrimus), and yellowtail rockfish (S. flavidus).

 

Purpose

This data product was developed to provide basic groundfish discard distribution information for a wide variety of audiences.  The West Coast Groundfish Observer Program conducts sampling of groundfish discarded by commercial fisheries along the entire continental U.S. West Coast.  The seventeen species included in this data product are among those of most interest to the fisheries management and commercial fishing communities.

 

Data Credits

NOAA Fisheries, Northwest Fisheries Science Center, Fishery Resource Analysis & Monitoring Division, West Coast Groundfish Observer Program, Seattle, WA.

 

Years

2002-2006

 

Bounding 

West  -125.849964

East -119.741712

North 48.536166

South 34.828762

 

Format

The Oracle table contains the following columns:

            SYS_ID

            GRID_ID

            LAT10KM

            LONG10KM

            FISHERY

            SURVEY_YEARS

            SCIENTIFIC_NAME

            COMMON_NAME

            DISCARD_RATE

 

Contact

West Coast Groundfish Observer Program

NOAA Fisheries, Northwest Fisheries Science Center

2725 Montlake Blvd E

Seattle, WA 98112-2097

Phone:  206-860-3381


DODS Relational Database Server

This data is being served by a DODS Relational Database Server (DRDS), which is a somewhat unusual instance of a DODS server. All of the data served by the DRDS is stored in a relational database management system (DBMS). Queries from DODS clients are translated into SQL queries and sent to the underlying DBMS. The reuturned data is read by the DRDS and returned to the requesting client.

Because the DRDS is essentially a front end to a DBMS, the DDS's have a somewhat different meaning than in other DODS servers. Each DDS served by the a DRDS represents a table in the underlying DBMS. Since queries to the DBMS will return an unknown amount of data, each DDS basically must contain a representation of the tables contents defined as a DODS sequence. Because of this it rarely makes sense for a client to request the entire "dataset", as this request will return the entire contents of the table. When requesting data from a DRDS, it is best to get the dataset information (using the .info extension on the DODS URL) and then build a constrained request that just returns data that is actually desired. This doesn't mean that the entire table cannot be requested and sent, it is simply a caution that each dataset/DDS/table may in fact be very large.

Server Functions:

unique(): This function gets used in the selection part of the DODS constraint expression. It requires no parameters. Calling this funcion will cause the return to contain only unique rows. This is useful for sifting through numerous identical fields, for example station data that contains instrument names. This is NOT very useful if you are trying to retrieve a ship track...
Example:

          http://nasty.dods.url/server/dataset.dods?var1,var2&unique()
  

Regular Expressions: The typical DODS server supports the full range regular expression syntax. THIS DODS server does not. Limited string matching is available. The wild card characters '.' and '.*' may used. The '[...]' notation for matching a range of characters may be used, but only to match a single character to a range of possiblities.
Examples:

          http://nasty.dods.url/server/dataset.dods?var1,var2&var3~=".*south.*"
          http://nasty.dods.url/server/dataset.dods?var1,var2&var3~=".south."
  

NOTE:

String fields in the DBMS may contain white space (spaces). In order for a constraint to match you must include the spaces. For example, if you wish to retrieve all data where a field called location has a value of "Southern Ocean", in your DODS URL you will have to represent the space between "Southern" and "Ocean" with the symbol "%20". Like this:
    location="Southern%20Ocean"
However, if the DODS URL is formed with a space like this:
    location="Southern Ocean"
It will not be handled correctly by the DRDS.

Have fun!