Calculate Catch Weights Using Length-Weight Relationships

This function calculates catch weights using length-weight relationships from FishBase. It processes catch data by mapping common names to scientific names, retrieving length-weight coefficients, and applying the length-weight equation to estimate catches.

Usage

calculate_catch(catch_df = NULL)

Arguments

catch_df

A tibble containing catch data with columns:

• submission_id: Unique identifier for the submission

• catch_taxon: Species or group name

• length_class: Length class in centimeters

• counts: Number of individuals

Value

A tibble containing the original catch data plus:

• catch_gr: Estimated catch weight in grams

Details

The function performs several steps:

1. Groups related species categories (e.g., combining sardines and pilchards)

2. Maps common names to scientific names using FishBase

3. Retrieves length-weight relationships for species in the area (C_Code = 508)

4. Calculates median length-weight coefficients for each species group

5. Estimates catch weights using the length-weight equation: W = a * L^b

Note

• Length-weight relationships are filtered for area code 508

• Median values of length-weight coefficients are used when multiple relationships exist

• Only relationships with no quality issues (EsQ is NA) are used

See also

preprocess_landings for data preprocessing steps

Examples

if (FALSE) { # \dontrun{
catch_estimates <- calculate_catch(preprocessed_catch_data)
} # }