Types of Data


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Database Elements

The Pacific States Marine Fisheries Commission hosts the Regional Mark Processing Center (RMPC). This office maintains the on-line Regional Mark Information System (RMIS) to facilitate exchange of CWT data among release agencies, sampling & recovery agencies, and other data users. The RMPC also serves as the U.S. site for exchanging U.S. CWT data with Canada for Pacific Salmon Treaty purposes. Canada houses a second complete copy of Pacific Coast wide CWT data sets.  

The CWT database houses information relating to the release, sample, and recovery of coded wire tagged salmonids throughout the Pacific region. These data flow to the RMPC in the form of files sent by electronic transfer, and must meet stringent validation criteria for inclusion in the permanent database.  

Users of the RMIS application must be familiar with the document: "CWT Data File Definition, Specification & Validation Version 4.1 ". It is very important that users of CWT data understand the information contained in this document in order to perform conclusive, accurate and responsible analysis of these data.   

There are four main classes of CWT data: Releases, Catch/Samples, Recoveries, and Locations. These classes of data are described below.




When a group of fish is released from a hatchery or other release site containing any number of coded wire tagged fish, the group is associated with a unique tag code. Any pertinent information from releasing agencies regarding the release group is submitted to the RMPC by the responsible state, provincial, or federal agencies.  

When groups of fish are released without coded wire tagged fish present, the release group is called an untagged/unassociated group.  The release group is assigned a 12 character alpha-numeric identifier.  This information is likewise submitted to the RMPC.  There are approximately 53,000 tagged release groups and approximately 112,000 untagged release groups in the database.   

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Tagged fish are sampled at various commercial, recreational, tribal and escapement fisheries Pacific Coast wide by sampling agencies.  These agencies usually record the sampling area, number caught, and percent of catch that was sampled and related information,  This information is called Catch/Sample data and is collected by sampling agencies for submission to the RMPC on a yearly basis by specific reporting agencies.  There are currently about 392,000 Catch/Sample records in the database.   

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When tags are removed from fish and decoded, the tag is linked to the specific location of catch, date of catch, fishery, and other related biological data.  Where possible, the ratio of the number of fish sampled to the total catch is multiplied by the total number of tags extracted to form the Estimated Number of fish.  These data are collected by sampling agencies for submission to the RMPC on a yearly basis along with Catch/Sample data.  Individual recovery records correspond to one observed (decoded) tag.    

Each recovery record has an associated "Status of Tag". This status is coded as follows:

"1" Tag read OK
"2" No tag
"3" Tag lost before read
"4" Tag not readable
"7" Unresolved discrepancy
"8" Head not processed
"9" Pseudo tag, blank wire  

In addition to passing rigorous validation tests, the status "1" recoveries must match by tag code with a tagged release group.  There are currently about 7.2 million status "1" recovery records in the database.   Recoveries with a status other than "1" are not included in reports.  There are currently about 1.9 million non-status "1" recoveries in the database.  

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Location Codes

The geographic locations of release, sample, and specific recovery of fish are also assembled by specific location reporting agencies .  Collectively, these are called Location data and are submitted to the RMPC along with all other classes of data.  

There are five types of locations.  Within each type of location, the location record is uniquely identified coast wide by a 19 character Location Code.  That code is associated with a textual description of the location and a geographical reference to the location.  Currently there are approximately 35,000 locations in the database.  

The five types of locations are described as follows:

  1. Recovery Site: Indicates as closely as possible the actual geographic place where a tagged fish was caught.  They are usually specified within larger Catch Areas in the sampling stratum.  This type of location is found only in Recovery data.
  2. Catch Area: Corresponds to geographic areas where sampling occurred for a given fishery.  They may encompass several recovery sites.  This type of location is found only in Catch/sample data.
  3. Hatchery: Specifies the name of the hatchery or rearing facility for non-wild release groups.  This type of location is found only in Release data.
  4. Release Site: Specifies the geographic release location of the release group.  It may differ from the hatchery.  This type of location is found only in Release data.
  5. Stock: Differs from all other locations in that they identify the brood stock or morphology of a release group rather than a geographic location.  Stocks usually correspond to the name of a stream or if the stock was mixed, a composite of stream names.  This type of location is found only in Release data.

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