Glossary of Coded Wire Tag Terms

The following terms are used throughout the Coded Wire Tag Laboratory. Each term is followed by a definition and clicking on the term will produce a list of possible values and each value's corresponding code.

Online Reports Page
Run a Facility Mapper Report
Run an Agency Report
Run a Commercial Survey Site Report
Run a Non-Commercial Survery Site Report
Run a Southeast Sport Report
Run a Contribution Summary Report
Run a Commercial Expansion Harvest Report
Run a Sport Expansion Report
Run a Recoveries by Fishery Report
Run a CWT Release Report
Run a Hatchery Release Report
Run a Number Sampled Report

Accounting Year
A 12 month period over which catch, recoveries, and expansions is summarized.

For all trolls gears, the Alaska Department of Fish and Game defines accounting year as starting on October 1 and ending on September 30 of the following calendar year to allow catch, recoveries and expansions from early winter troll (October-December) and late winter troll (January-April) to be summarized together.

For all net, and other gears, the department defines accounting year as starting January 1 and ending December 31.

An acronym for the educational, private, or governmental entity conducting the study and responsible for the project.

Name of the original, wild broodstock from which transplanted fish originated.

The Alaska Department of Fish and Game maintains a catalog of names identifying all bodies of freshwater where anadromous fish breed. As of this writing, it may be reviewed on the web at A-Stream numbers are based on a scheme which follows a particular body of freshwater from the statistical area of its marine estuary up through tributaries. A location that passes through many branches before reaching the ocean could have a very long A-Stream number.

Bi-week Calendar
Sport Biweeks run from Monday through Sunday. Biweek 1 begins on January 1.
Biweek 2 begins on the third Monday of the year.
All biweeks except the first and last are exactly 14 days long.
The last biweek of the year ends on December 31.

Brood (brood_year)
The year when the adults returned to produce a given release group. In some wild stock tagging projects, when more than one brood year is present, the dominant or first brood year is reported.

Canada Watershed Codes
The province of British Columbia maintains the most popular stream catalog for identifying freshwater locations in both BC and Yukon Territory. Canada Watershed applies only to certain samples taken on trans-boundary river systems. For freshwater samples taken wholly within Alaska, the anadromous stream number ("A-Stream") is employed instead.

Catch Sample Factor
Sum of fish caught divided by sum of fish sampled in same strata.
    #caught (N) / #sampled (N2)

Clip Status
The presence and quality of the adipose clip as reported by sampler inspecting fish.

Estimated number of harvested fish belonging to the same release group as a recovered coded wire tag. Contribution depends on the combination of strata and sampling methodology applied for tag detection.

Visual sampling method (ad-clipped fish only)
    Expansion Factor * Mark Selective Fishery Tag Ratio (Mark Selective Fisheries only)
    Expansion Factor * Single Index Tag Ratio (all other fisheries)
Electronic sampling method (ad-clipped and not ad-clipped fish)
    Electronic Expansion Factor * Electronic Tag Ratio

The individual responsible for reporting tag code data to PSMFC.

Coded wire tag

A specific area defined for fisheries management, many districts make up a region. Districts roughly correspond to how salmon fisheries developed in the state with some districts primarily associated with a particular gear type targeting specific returns of salmon. The Board of Fisheries typically defines salmon management plans that define how a fishery is conducted including allowed gear, fishing periods, and other aspects for districts in a region.

Expansion Factor (Estimated)
Applied to tag codes recovered in visual sampling methodologies.
    Catch Sample Factor * Lost Head Factor * Lost Tag Factor

The general classification of the type of experiment being conducted on non-production releases of tagged hatchery fish. Provided for Alaskan releases only.

The hatchery or facility where fish were reared.

Fishing Site
Used by Sport Fish Division of ADF&G in Southeast (SE) Alaska. Due to annual changes, contact SE Sport Fish Division for information on codes.

The method or means used to commercially catch fish.

Gear Class
Used to combine related gears. Currently gear and gear_class for all gears except for power and hand troll are the same. The gear_class for power and hand troll is troll.

As used here distinguishes different types of commercial fisheries.

Length Type
Length_type_code describes what measurement was taken. Measurement is in millimeters.

The facility name for hatchery release or, if preceded by (W), the wild brood stock name.

Lost Head Factor
Sum of heads collected divided by sum of heads scanned for presence of a tag in same strata.
    #ad clips (A1) / #received (A2)

Lost Tag Factor
Sum of tags detected divided by tags successfully decoded1 in same strata.
    #detected (M1) / #decoded (M2)
1 Fish identified as having a Coded Wire Tag may be lost in transfer to or by the lab, tags themselves may be lost or are unreadable, which will produce a lost tag factor greater than one.

Describes the type of mark applied to a group of fish prior to release as a means of identification at a later time.

Mark Selective Fishery
Fishery in which only marked fish are retained.

The type of counting procedure used to estimate the number of unmarked fish represented by this tag code that were released.

In some fisheries, like the SE troll fisheries, openings routinely span more than one statistical week. When calculating expansion factors we pool catch, sample and recovery statistics into time periods which include all weeks in an opening.
Periods used for Southeast seine fisheries are two sequential statweeks with the first, and last two periods established as:
Period 1=Statweeks 1-27
Period 7=Statweeks 38-41
Period 8=Statweeks 42-53

Pacific Salmon Commission

Pacific States Marine Fisheries Commission

This area definition was adopted to better summarize coded wire tag contributions to the Southeast Alaska troll fishery where boats may fish in multiple districts in a single trip. Quadrants are made up of multiple districts. Southeast Alaska, for instance, is broken up into 4 areas called, Northwest, Northeast, Southeast and Southwest quadrants. (It was the prevalent use of this area in Southeast Alaska that accounts for the name quadrant). Elsewhere in the state, quadrants are aligned with management areas.

Code used to distinguish hatchery reared tag groups from wild stock tagging projects.

Release Type
Identifies if a tag code was used to represent hatchery production groups or hatchery experimental release groups, etc.

As used here, defined as the season in which the majority of brood stock adults leave a marine environment and enter fresh water on the spawning migration.

Sampling Type
Identifies how sampling data were collected. Random samples are collected as part of a recognized sampling program which collects data randomly with respect to the parameters or strata used in analysis. Select and voluntary samples are collected outside recognized sampling programs. Select samples are non-random data collected from a fishery with a recognized sampling program. Voluntarily samples are non-random data collected from a fishery without a recognized sampling program.

Seine Area
In Southeast Alaska some districts are combined for calculation of CWT contributions to traditional seine fisheries. The following seine areas and the respective districts are used:
SASI=District 101 and 102
SASO=Districts 103 and 104
SACI=Districts 105, 106, and 107
SACO=Districts 109 and 110
SA11=District 111
SA12=District 112
SA13=District 113
SA14=District 114

The gender of a particular fish in a sample expressed as either male or female.

Location where tag group was released

Used to distinguish major types of fisheries, like sport, commercial (common property), cost recovery, escapement, hatchery racks, etc.

The sub-genus classification of salmonids being sampled.

Sport Harvest
As used here distinguishes different types of sport fisheries, like marine boat fisheries, derbies, freshwater fisheries, etc.

Sport Period Calendar
Seasonal Period 1 runs from biweek 1-12
Seasonal Period 2 runs from biweek 13-15
Seasonal Period 3 runs from biweek 16-yearend

The age at release of a group of tagged fish defined by certain growth or developmental parameters.

Statistical (Stat) Week Calendar
  1. The ADF&G Statistical Week is 7 days long and runs from Sunday through Saturday.
  2. The first Statistical week of the year may be less than 7 days and ends on the first Saturday.
  3. Subsequent weeks are numbered chronologically through the end of the year.
  4. The statistical week (stat_week_cwt) reported on most reports and used for expansion factor calculation is based on different recorded dates (i.e. date_sold, date_catch_end, date_catch_begin or date_sampled) dependent on the sampling program. Stat_week_cwt for commercial and cost recovery fisheries is generally based on date_caught. Stat_week_cwt for rack, escapement, sport and personal use samples is based on date_sampled. (For more specific information please contact the MTA Lab).

Identifies the US state or Canadian province where tagged fish were released.

Statistical (Stat) Area
Stat Area for short, and also called a sub-district, this is the most granular level of fisheries management area definitions. A single district is broken down into multiple Sub-Districts.

A group of fish originating from a single freshwater system. If a stock is transplanted to another system or facility for release, it retains the original stock name until eggs taken from progeny of the original release are returning to the new system. If the fish originated from eggs taken at a hatchery rack, then a name associated with the hatchery is used to describe the stock.

A set of categories used to group data.

Commercial Strata
Strata used to group and summarize sets of commercial catch and sample data for Coded Wire Tag expansion and contribution estimates are: Gear Class, Harvest, Time, and Location.

The Coded Wire Tag laboratory provides estimates for all levels of strata and has identified the following as providing optimal accuracy.1

Optimal Strata for Commercial Expansions
Gear ClassHarvestTime ValueArea Value
TrollMark Selective FisheryPeriodQuadrant
TrollTerminalStatistical WeekStatistical Area
TrollSpring TrollPeriodStatistical Area
TrollOtherStatistical WeekDistrict
Purse SeineTraditionalPeriodSeine Area
Purse SeineOtherStatistical WeekDistrict
AnyPrivate Non-ProfitStatistical WeekStatistical Area
All other combinations of Gear Class and HarvestStatistical WeekDistrict
Sport Strata
The strata used to group and summarize sport catch and sample data are: Survey Site, Sport Harvest, Time, and Species. The following are the preferred strata for analyzing sport expansion and contribution data.

Optimal Strata for Sport Expansions
 GearSport HarvestTime ValueArea Value
Recent SportAnyAnyBi-WeekSurvey Site
Historical SportAnyAnyPeriodSurvey Site
1 Using combinations of strata not listed above may result in less accurate or erroneous contribution estimates.
2 Statistical Week is assigned based on date first caught for all Net harvest.
3 Statistical Week is assigned based on date last caught for all Troll harvest with the exception of some historical data created before date first and last caught were captured; this data may be based on date sold or landed.

See Statistical Week definition for more rules and uses.

Smallest area defined for fisheries management, Districts are broken down into Sub-Districts for management purposes. Sub-districts are used to describe distinct Statistical (Stat) Areas.

Subsample Factor
The subsample factor is the total number of unclipped fish observed in the sample divided by the number of unclipped fish inspected for coded wire tags. This factor is calculated using database fields as:
    Subsample Factor = (#sampled for adipose clips (N2) - #ad clips observed (A1)) / #no-ad clips inspected for tags (A3)

Survey Site
Identifies sampling places throughout the state.
For commercial samples, this is typically the location of the buying processor, NOT the place caught. Coded Wire Tag and Thermal Mark share a common set of Survey Sites, although a site used by CWT may not necessarily be used for thermal mark sampling and vice versa. Survey Site is specific to Mark, Tag and Age Lab data and does not apply to other data such as fish tickets.
For sport specimen, this is typically the location where the fishermen return with their catch, often the town where a dock is located and a department sampler collected the data.
For escapement samples, this is typically the location name of the freshwater system where specimens were collected.
For rack samples, this is typically the name of the hatchery where the specimens were collected.

Used here to grossly describe the projected long term life expectancy of a group of fish.

Tag Ratio
Expresses the number of fish in the sample population that each recovered tag represents. The presence or absence of external marks on fish, the selectivity or non-selectivity of a fishery and the sampling method affects the number of fish that each tag represents in the sample population. Tag Ratio is calculated accordingly:
    Single Index Tag Ratio: #fish released / #fish ad-clipped and tagged
    Electronic Tag Ratio: #fish released / #fish tagged (regardless of mark type)
    Marked Selected Fishery Tag Ratio: #ad-clipped fish / #fish ad-clipped and tagged

Tag Status
Identifies the processing disposition of a sampled head. Catalogs if a head was lost, not received yet, a tag was found and read OK, etc.

Tag Type
Defines which type of internal coded wire tag was injected into fish in this release group.

Troll Period Calendar
A group of consecutive statistical weeks used for measuring commercial troll catch. The first period is 1 and begins at the beginning of stat week 1. After a certain number of stat weeks, period 2 begins, then period 3, etc. The actual weeks a period covers varies from year to year, as managers determine what best fits the characteristics of the troll fishery. The number of periods in a particular calendar year also varies, depending on the desires of the resource managers. For example, there were 3 periods in 1976 but 9 periods in 1989.

Identifies if fish were released, recovered, caught or sampled in freshwater or saltwater.

Water PSC Short Name
Identifies in PSC reporting format if fish were released, recovered, caught or sampled in freshwater or saltwater.

Why Status 7
Categorizes the reason why a tag was assigned a tag_status = 7 (Nonsense). Only available for tags recovered in Alaskan waters.

  1. Unless otherwise noted, expansion factor (Preferred Expansion Factor) and contribution (Preferred Contribution) estimates reported on most Mark, Tag, and Age Lab reports for all commercial fisheries are expanded by year|harvest_code|species|gear_class|week|district. Exceptions to this are: traditional troll which uses period|quadrant; experiment and cost recovery fisheries which use week|stat_area (district-subdistrict).

  2. The statistical week (stat_week_cwt) reported on most reports and used for expansion factor calculation is based on different recorded dates (i.e. date_sold, date_catch_end or date_sampled) dependent on the sampling program. Stat_week_cwt for commercial and cost recovery fisheries is based on date_sold. Stat_week_cwt for rack, escapement, sport and personal use samples is based on date_sampled.