add_area_stratification: Add Survey Area Stratified Abundances and Biomasses

In gulfofmaine/gmRi: Utility Functions for GMRI Research Team

Add Survey Area Stratified Abundances and Biomasses

Description

Take the survdat data which has been cleaned with gmRi::gmri_survdat_prep, that is paired with length weight relationships using gmRi::add_lw_info and estimate the area stratified catch rates and their expected abundances and biomasses when those catch rates are applied to the total areas of their respective strata.

Area-stratified catch rates are calculated independently for each species, every year, within each strata, and by each season. i.e. 1982 spring cpue of acadian redfish informs the area-stratified catch of acadian redfish in spring of 1982.

Constants for the area-towed and the catchability coefficient are as followed: - Area covered by an albatross standard tow in km2 = 0.0384 - Catchability coefficient - ideally should change for species guilds: q = 1

Usage

add_area_stratification(
  survdat_weights,
  include_epu = F,
  box_location = "root|cloudstorage"
)

Arguments

survdat_weights	Input dataframe, produced by add_lw_info
include_epu	Flag for calculating the EPU rates in addition to the stratum regions we use.
box_location	String indicating value to pass to 'boxpath_switch'

Value

survdat df with fields for area stratified values

Examples

# not run
# add_area_stratification(survdat_weights = survdat_lw, include_epu = F)

gulfofmaine/gmRi documentation built on Jan. 26, 2025, 5:12 a.m.