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Diversity and Concentration of the Catch

Source: R/diversity_concentration.R
diversity_concentration.Rd

This function computes, for each year:

  • the number of species reported (items identified to species with catch) and the number of countries with catch;

  • the Shannon diversity index of the catch over FAO species items, \(H = -\sum p_i \ln p_i\), where \(p_i\) is the share of item \(i\);

  • the Herfindahl-Hirschman index (HHI) of species items and of countries, the sum of squared percentage shares (0 to 10 000; above 2 500 is usually read as highly concentrated);

  • the share of the top_n largest species items and countries.

Usage

diversity_concentration(
  area_data,
  top_n = 5,
  plot = TRUE,
  table = TRUE,
  lang = NULL,
  pptx = getOption("faofishingreport.pptx", FALSE),
  plot_show = fao_setting("plot_show"),
  label = NULL
)

Arguments

area_data

FAO catch data: fishing_area_data()$area_data, or any subset of load_fao_data() (e.g. one country, or several fishing areas).

top_n

The number of largest species and countries for the top share. Default is 5.

plot

A logical value. If TRUE (default), charts are saved in figures/png/summary/.

table

A logical value. If TRUE (default), tables are saved in tables/.

lang

The language of the chart text and names: "en" (English), "zh" (Chinese) or "both" (Chinese and English). Default is NULL, which uses the language set with fao_settings() ("en" unless changed).

pptx

A logical value. If TRUE, charts are also saved as editable PowerPoint files in figures/pptx/summary/. Default is FALSE, which can be changed for all functions with fao_settings(pptx = TRUE).

plot_show

A logical value. If TRUE, each chart is also drawn in the plot window (e.g. the Plots pane of RStudio) as it is saved, to look at it at once. Default is FALSE, which can be changed for all functions with fao_settings(plot_show = TRUE). The charts are saved as files (plot = TRUE) either way.

label

The name used in the output file names. Default is the fishing area (or the country) of the data.

Value

Invisibly, a data frame with one row per year.

See also

Other summary analyses: area_overview(), coastal_distant(), country_group_summary(), data_quality(), peak_trend(), regime_shift(), species_group_composition(), stock_status()

Examples

if (FALSE) { # \dontrun{
FAO27 <- fishing_area_data("Atlantic, Northeast", plot = FALSE)
diversity_concentration(FAO27$area_data, lang = "zh")
} # }