SPslope {DLMtool} | R Documentation |
A management procedure that makes incremental adjustments to TAC recommendations based on the apparent trend in recent surplus production. Based on the theory of Mark Maunder (IATTC)
SPslope( x, Data, reps = 100, plot = FALSE, yrsmth = 4, alp = c(0.9, 1.1), bet = c(1.5, 0.9) )
x |
A position in the data object |
Data |
A data object |
reps |
The number of stochastic samples of the MP recommendation(s) |
plot |
Logical. Show the plot? |
yrsmth |
Years over which to smooth recent estimates of surplus production |
alp |
Condition for modifying the Data (bounds on change in abundance) |
bet |
Limits for how much the Data can change among years |
Note that this isn't exactly what Mark has previously suggested and is stochastic in this implementation.
The TAC is calculated as:
where r is the ratio of predicted biomass in next year to biomass in
current year \bar{C} is the mean catch over the last yrmsth
years, α_1
and α_2 are specified in alp
, \textrm{bet}_1 and \textrm{bet}_2
are specified in bet
, \textrm{SP} is estimated surplus production in most recent year,
and:
M = 1-\textrm{bet}_1 \frac{B_y - \tilde{B}_y}{B_y}
where B_y is the most recent estimate of biomass and \tilde{B} is the predicted biomass in the next year.
An object of class Rec-class
with the TAC
slot populated with a numeric vector of length reps
See Data-class
for information on the Data
object
SPslope
: Abun, Cat, Ind, Year
See Online Documentation for correctly rendered equations
T. Carruthers
http://www.iattc.org/Meetings/Meetings2014/MAYSAC/PDFs/SAC-05-10b-Management-Strategy-Evaluation.pdf
Other Surplus production MPs:
Fadapt()
,
Rcontrol()
,
SPMSY()
,
SPSRA()
,
SPmod()
SPslope(1, Data=MSEtool::Atlantic_mackerel, plot=TRUE)