turnover: turnover estimate turnover of vessels from catch by vessel by...

In haddonm/rforcpue: Functions to Assist With The Analysis of CPUE Data

turnover estimate turnover of vessels from catch by vessel by year data

Description

turnover estimates turnover of vessels from catch by vessel by year data. To specify the minimum number of years that a vessel needs stay in the fishery, then give a value to the variable minyrs. needs MODIFICATION

Usage

turnover(x, minyrs = 1)

Arguments

x	A matrix of a continuous numeric property by year, the original usage was to plot catch-by-vessel against year
minyrs	limits the analysis to those vessels that remain in the fishery for at least minyrs years - which would eliminate the occasional opportunistic fisher who only fishes for one or two years, or whatever minimum is selected. Vessels with zero catches are not included in case zeros and NAs are counted as starting and leaving the fishery.

Value

a matrix of years by Continue, Leave, Start, Total

Examples

require(rforcpue)
data(sps)
cbv <- tapply(sps$catch_kg,list(sps$Vessel,sps$Year),sum,na.rm=TRUE)/1000
turnover(cbv)

haddonm/rforcpue documentation built on Oct. 12, 2024, 11:55 p.m.