estimate_weight_length: Calculate weight-length relationship parameters

In nwfsc-assess/nwfscSurvey: Northwest Fisheries Science Center Survey

Calculate weight-length relationship parameters

Description

Estimate parameters of the weight-length relationship for each sex and all sexes combined, where the latter includes unsexed fish.

Usage

estimate_weight_length(
  data,
  col_length = "lengthcm",
  col_weight = "weightkg",
  verbose = FALSE
)

Arguments

data	A data frame containing empirical weights and lengths from sampled fish. Sexes should be available in the column sex or SEX.
col_length	A numeric or character value specifying the column to use in data for length information. These lengths are assumed to be in centimeters. The default value is lengthcm, which is added to a data set automatically when running cleanPacFIN.
col_weight	A numeric or character value specifying the column to use in data for weight information. These weights are assumed to be in kilograms The default value is weightkg, which is added to a data set automatically when running cleanPacFIN. Using kilograms is the default because Stock Synthesis assumes the weight-length parameters are calculated using centimeters and kilograms. The reported values are easily scaled to give you results in grams if you wish to have more standard parameter estimates.
verbose	A logical that specifies if you want to print messages and warnings to the console. The default is TRUE.

Value

A data frame of weight-length parameters by sex. Parameters A and B are in the appropriate units to input into Stock Synthesis Wtlen_1_Fem and Wtlen_2_Fem, or Wtlen_1_Mal and Wtlen_1_Mal, parameters in the control file. Values of NA are returned for models that did not have enough data to properly estimate the parameters. This will happen when there are no females in your data set, for example.

Author(s)

Kelli F. Johnson and Chantel Wetzel

nwfsc-assess/nwfscSurvey documentation built on April 29, 2024, 9:51 p.m.