catch_by_station: Catch per station for each length class

In fishvice/pax: tidy fish data wrangling functions

Description

Calculates the catch per station.

Similar as afli.per.stod in the fjolst-package except returns abundance and biomass per length class, as well as abundance less than and biomass greater than a given length class.

Usage

catch_by_station(Stations, Lengths, lwcoeff = c(0.01, 3), std = c("none",
  "towlength", "areaswept"), std.towlength = 4, std.towwidth = 17)

Arguments

Stations	A dataframe with station information. Required columns are id (unique station id), year, towlength and strata (the strata identifyer).
Lengths	A dataframe with length frequency measurements. Required columns are id (station id), length (the length class) and n (the number of fish measured) where the latter are the "raised" numbers.
lwcoeff	A vector of length 2, containing parameter a and b of the length weight relationship.
std	Character specifying standardization. Valdi character are "none", "towlength" or "areaswept".
std.towlength	Standard towlength in nautical miles. Default is 4 (not used if std = "none").
std.towwidth	Standard width of trawl in meters. Default is 17 (only used if std = "areaswept").

Value

A dataframe containing the follow columns ..

fishvice/pax documentation built on May 16, 2019, 1:13 p.m.