LengthComposition: Length composition

In nmfs-fish-tools/data_dictionary: Collaborative tool to improve consistency in terminology and develop a framework of tools for fisheries science.

Length composition

Description

A matrix of proportions of observed lengths per length categories that are typically summarized by time period, data source, and sex.

Usage

LengthComposition

Format

A schema with the following fields:

Examples

Rationale

Composition is more commonly used than frequency but storing data as compositions removes information about the number of fish that were included in the sample. Typically, the sample size associated with a given composition will not be based on the number of fish and is instead based on the number of tows, and thus, it is important to store the data as frequencies rather than compositions such that information is not lost.

Alternatives

length frequency, length observation

Range of possible values

0–1

Units

nmfs-fish-tools/data_dictionary documentation built on July 27, 2024, 12:20 p.m.