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length_length

Source: R/population_dynamics.R
length_length.Rd

return a table of lengths

Usage

length_length(
  species_list = NULL,
  fields = NULL,
  server = getOption("FISHBASE_API", "fishbase"),
  version = get_latest_release(),
  db = default_db(server, version),
  ...
)

Arguments

species_list

A vector of scientific names (each element as "genus species"). If empty, a table for all fish will be returned.

fields

a character vector specifying which fields (columns) should be returned. By default, all available columns recognized by the parser are returned. Mostly for backwards compatibility as users can subset by column later

server

can be set to either "fishbase" or "sealifebase" to switch between databases. NOTE: it is usually easier to leave this as NULL and set the source instead using the environmental variable `FISHBASE_API`, e.g. `Sys.setenv(FISHBASE_API="sealifebase")`.

version

a version string for the database, will default to the latest release. see [get_releases()] for details.

db

the

...

unused; for backwards compatibility only

Value

a table of lengths

Details

This table contains relationships for the conversion of one length type to another for over 8,000 species of fish, derived from different publications, e.g. Moutopoulos and Stergiou (2002) and Gaygusuz et al (2006), or from fish pictures, e.g. Collette and Nauen (1983), Compagno (1984) and Randall (1997). The relationships, which always refer to centimeters, may consist either of a regression linking two length types, of the form: Length type (2) = a + b x Length type (1) Length type (2) = b' x Length type (1) The available length types are, as elsewhere in FishBase, TL = total length; FL = fork length; SL = standard length; WD = width (in rays); OT = other type (to be specified in the Comment field). When a version of equation (1) is presented, the length range, the number of fish used in the regression, the sex and the correlation coefficient are presented, if available. When a version of equation (2) is presented, the range and the correlation coefficient are omitted, as the ratio in (2) will usually be estimated from a single specimen, or a few fish covering a narrow range of lengths.

References

http://www.fishbase.org/manual/english/PDF/FB_Book_CBinohlan_Length-Length_RF_JG.pdf

Examples

if (FALSE) { # interactive()
if (FALSE) {
length_length("Oreochromis niloticus")
}
}