The principal document for populating this operating model was the CASAL stock assessment
The operating model was populated from the Maximum Posterior Density estimates from CASAL using the MSEtool function CASAL2OM. Uncertainty in depletion (SSB2015 / SSB0) and the age and year specific dynamics of the CASAL assessment were added to the operating model via the custom parameter slot (cpars) including:
Size vulnerability (V)
Recruitment variation (Perr)
Historical patterns in exploitation rate (Find)
Maturity-at-age ogives
However CASAL also includes point estimates for many parameters such as natural mortality rate, which are likely to quite uncertain.
To address this uncertainty was also added in the build.r script to
current stock depletion (and hence historical fishing rate) - a lognoraml random variable with CV of 10 (similar uncertainty to run 6 of the model in the assessment file, Figure 14, page 26)
Natural mortality rate - a lognormal random variable with CV of 10%. This is a guess and somewhat precise based on the typical level of uncertainty assumed in M for other stocks.
Discarding rate (slot DR). In this preliminary model I assumed this was zero.
TAC TAE and Size limit adherence (slots TACFrac, TACSD, TAEFrac, TAESD, SizeLimFrac, SizeLimSD). I had no idea how well management advice was adhered to and assumed it was managed perfectly without error.
Observation model parameters. I had no idea how well data are observed but specified the Precise_Unbiased basket of observation error parameters. A possible robustness test could use the parameters of the Imprecise_Biased observation model, for example.
The OM rdata file can be downloaded from here
Download and import into R using myOM <- readRDS('OM.rdata')
Species: Dissostichus eleginoides
Common Name: Patagonian toothfish
Management Agency: CCAMLR
Region: Southern Ocean
Sponsor: Marine Stewardship Council
Latitude: -53
Longitude: -73.5
OM Name: Name of the operating model: Patagonian toothfish Heard Island and McDonald Islands
nsim: The number of simulations: 192
proyears: The number of projected years: 50
interval: The assessment interval - how often would you like to update the management system? 2
pstar: The percentile of the sample of the management recommendation for each method: 0.5
maxF: Maximum instantaneous fishing mortality rate that may be simulated for any given age class: 2
reps: Number of samples of the management recommendation for each method. Note that when this is set to 1, the mean value of the data inputs is used. 1
Source: A reference to a website or article from which parameters were taken to define the operating model
CCAMLR
maxage: The maximum age of individuals that is simulated (there is no plus group ). Single value. Positive integer
Specified Value(s): 35
From CASAL.
R0: The magnitude of unfished recruitment. Single value. Positive real number
Specified Value(s): 6585060
From CASAL Unless MPs make catch recommendations in specific units (e.g. 200 tonnes) then R0 is just a scaler and it not consequential to MSE results.
M: Natural mortality rate. Uniform distribution lower and upper bounds. Positive real number
Specified in cpars: 0.12, 0.2
From CASAL. We add uncertainty in this using cpars, see above.
M2: (Optional) Natural mortality rate at age. Vector of length maxage . Positive real number
Slot not used.
Mexp: Exponent of the Lorenzen function assuming an inverse relationship between M and weight. Uniform distribution lower and upper bounds. Real numbers <= 0.
Specified Value(s): 0, 0
We assumed size-invariant M.
Msd: Inter-annual variability in natural mortality rate expressed as a coefficient of variation. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0, 0.01
We assume no variation in M among years.
Histograms of 48 simulations of M
, Mexp
, and Msd
parameters, with vertical colored lines indicating 3 randomly drawn values used in other plots:
The average natural mortality rate by year for adult fish for 3 simulations. The vertical dashed line indicates the end of the historical period:
Natural mortality-at-age for 3 simulations in the first historical year, the last historical year (i.e., current year), and the last projected year:
Natural mortality-at-length for 3 simulations in the first historical year, the last historical year (i.e., current year), and the last projected year:
h: Steepness of the stock recruit relationship. Uniform distribution lower and upper bounds. Values from 1/5 to 1
Specified Value(s): 0.75, 0.75
From CASAL. A point value.
SRrel: Type of stock-recruit relationship. Single value, switch (1) Beverton-Holt (2) Ricker. Integer
Specified Value(s): 1
As the CASAL assessment: the Beverton-Holt model.
Perr: Process error, the CV of lognormal recruitment deviations. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified in cpars: 0.25, 3.57
From the CASAL assessment.
AC: Autocorrelation in recruitment deviations rec(t)=ACrec(t-1)+(1-AC)sigma(t). Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.23, 0.23
From the CASAL assessment.
Histograms of 48 simulations of steepness (h
), recruitment process error (Perr
) and auto-correlation (AC
) for the Beverton-Holt stock-recruitment relationship, with vertical colored lines indicating 3 randomly drawn values used in other plots:
Period: (Optional) Period for cyclical recruitment pattern in years. Uniform distribution lower and upper bounds. Non-negative real numbers
Slot not used.
Amplitude: (Optional) Amplitude in deviation from long-term average recruitment during recruitment cycle (eg a range from 0 to 1 means recruitment decreases or increases by up to 100% each cycle). Uniform distribution lower and upper bounds. 0 < Amplitude < 1
Slot not used.
Linf: Maximum length. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 2116.29, 2116.29
From the CASAL assessment.
K: von Bertalanffy growth parameter k. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.03, 0.03
From the CASAL assessment.
t0: von Bertalanffy theoretical age at length zero. Uniform distribution lower and upper bounds. Non-positive real numbers
Specified Value(s): -5.31, -5.31
From the CASAL assessment.
LenCV: Coefficient of variation of length-at-age (assumed constant for all age classes). Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.13, 0.13
A resonably wide uncertainty at length in age was specified.
Ksd: Inter-annual variability in growth parameter k expressed as coefficient of variation. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.01, 0.02
No data is available on changes in growth over time. The range was set to allow a small amount of inter-annual variation in the K parameter.
Linfsd: Inter-annual variability in maximum length expressed as a coefficient of variation. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.01, 0.02
No data is available on changes in growth over time. The range was set to allow a small amount of inter-annual variation in the Linf parameter.
Histograms of 48 simulations of von Bertalanffy growth parameters Linf
, K
, and t0
, and inter-annual variability in Linf and K (Linfsd
and Ksd
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
The Linf and K parameters in each year for 3 simulations. The vertical dashed line indicates the end of the historical period:
Sampled length-at-age curves for 3 simulations in the first historical year, the last historical year, and the last projection year.
L50: Length at 50 percent maturity. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 1058.14, 1058.14
From the CASAL Assessment.
L50_95: Length increment from 50 percent to 95 percent maturity. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 211.63, 211.63
From the CASAL assessment.
Histograms of 48 simulations of L50
(length at 50% maturity), L95
(length at 95% maturity), and corresponding derived age at maturity parameters (A50
and A95
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
Maturity-at-age and -length for 3 simulations in the first historical year, the last historical year (i.e., current year), and the last projected year:
D: Current level of stock depletion SSB(current)/SSB(unfished). Uniform distribution lower and upper bounds. Fraction
Specified in cpars: 0.51, 0.77
Uncertainty in the depletion is imposed around the MPD estimate of the model.
Fdisc: Fraction of discarded fish that die. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.1, 0.1
We assume the same discard mortality as tagging.
Histograms of 48 simulations of depletion (spawning biomass in the last historical year over average unfished spawning biomass; D
) and the fraction of discarded fish that are killed by fishing mortality (Fdisc
), with vertical colored lines indicating 3 randomly drawn values.
a: Length-weight parameter alpha. Single value. Positive real number
Specified Value(s): 0
From the CASAL assessment.
b: Length-weight parameter beta. Single value. Positive real number
Specified Value(s): 3.21
From the CASAL assessment.
Size_area_1: The size of area 1 relative to area 2. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1, 0.1
A mixed stock is assumed
Frac_area_1: The fraction of the unfished biomass in stock 1. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1, 0.1
A mixed stock is assumed
Prob_staying: The probability of inviduals in area 1 remaining in area 1 over the course of one year. Uniform distribution lower and upper bounds. Positive fraction.
Specified Value(s): 0.5, 0.5
A mixed stock is assumed
Histograms of 48 simulations of size of area 1 (Size_area_1
), fraction of unfished biomass in area 1 (Frac_area_1
), and the probability of staying in area 1 in a year (Frac_area_1
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
nyears: The number of years for the historical spool-up simulation. Single value. Positive integer
Specified Value(s): 34
The assessment is from 1982 - 2015
Spat_targ: Distribution of fishing in relation to spatial biomass: fishing distribution is proportional to B^Spat_targ. Uniform distribution lower and upper bounds. Real numbers
Specified Value(s): 1, 1
We use the default assumption that effort distributed in proportion to density.
EffYears: Years representing join-points (vertices) of time-varying effort. Vector. Non-negative real numbers
From the CASAL assessment.
EffLower: Lower bound on relative effort corresponding to EffYears. Vector. Non-negative real numbers
From the CASAL assessment.
EffUpper: Upper bound on relative effort corresponding to EffYears. Vector. Non-negative real numbers
From the CASAL assessment.
EffYears | EffLower | EffUpper |
---|---|---|
1982 | 0.000 | 0.000 |
2015 | 0.000 | 0.000 |
1982 | 0.000 | 0.000 |
2015 | 0.000 | 0.000 |
1982 | 0.000 | 0.000 |
2015 | 0.000 | 0.000 |
1982 | 0.000 | 0.000 |
2015 | 0.000 | 0.000 |
1982 | 0.000 | 0.000 |
2015 | 0.000 | 0.000 |
1982 | 0.000 | 0.000 |
2015 | 0.000 | 0.000 |
1982 | 0.000 | 0.000 |
2015 | 0.000 | 0.000 |
1982 | 0.000 | 0.000 |
2015 | 0.927 | 0.927 |
1982 | 1.960 | 1.960 |
2015 | 1.840 | 1.840 |
1982 | 1.950 | 1.950 |
2015 | 1.700 | 1.700 |
1982 | 1.640 | 1.640 |
2015 | 1.750 | 1.750 |
1982 | 1.800 | 1.800 |
2015 | 1.770 | 1.770 |
1982 | 1.650 | 1.650 |
2015 | 1.580 | 1.580 |
1982 | 1.610 | 1.610 |
2015 | 1.640 | 1.640 |
1982 | 1.670 | 1.670 |
2015 | 1.670 | 1.670 |
1982 | 1.830 | 1.830 |
2015 | 1.860 | 1.860 |
1982 | 1.920 | 1.920 |
2015 | 3.220 | 3.220 |
Esd: Additional inter-annual variability in fishing mortality rate. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.1, 0.1
From the CASAL assessment.
Histograms of 48 simulations of inter-annual variability in historical fishing mortality (Esd
), with vertical colored lines indicating 3 randomly drawn values used in the time-series plot:
Time-series plot showing 3 trends in historical fishing mortality (OM@EffUpper
and OM@EffLower
or OM@cpars$Find
):
qinc: Average percentage change in fishing efficiency (applicable only to forward projection and input controls). Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0, 0
In the future, is a unit of effort going to lead to higher fishing mortality (positive qinc) or lower fishing mortality (negative qinc). We set the % annual increase to be very close to zero. We may wish to revisit this assumption after discussions in the workshop.
qcv: Inter-annual variability in fishing efficiency (applicable only to forward projection and input controls). Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.01, 0.02
Interannual variability in fishing efficiency. We allow for some variability in fishing efficiency among years, but may wish to adjust the range for this parameter after discussions in the workshop.
Histograms of 48 simulations of inter-annual variability in fishing efficiency (qcv
) and average annual change in fishing efficiency (qinc
), with vertical colored lines indicating 3 randomly drawn values used in the time-series plot:
Time-series plot showing 3 trends in future fishing efficiency (catchability):
L5: Shortest length corresponding to 5 percent vulnerability. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 529.07, 529.07
From the CASAL assessment.
LFS: Shortest length that is fully vulnerable to fishing. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 1058.14, 1058.14
From the CASAL assessment.
Vmaxlen: The vulnerability of fish at Stock@Linf . Uniform distribution lower and upper bounds. Fraction
Specified Value(s): 1, 1
From the CASAL assessment.
isRel: Selectivity parameters in units of size-of-maturity (or absolute eg cm). Single value. Boolean.
Specified Value(s): F
The selectivity parameters are set as absolute sizes (not relative to the size of maturity).
LR5: Shortest length corresponding ot 5 percent retention. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0, 0
We assume that discarding is size independent
LFR: Shortest length that is fully retained. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0, 0
We assume that discarding is size independent
Rmaxlen: The retention of fish at Stock@Linf . Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 1, 1
We assume that discarding is size independent
DR: Discard rate - the fraction of caught fish that are discarded. Uniform distribution lower and upper bounds. Fraction
Specified Value(s): 0, 0
We specify a wide range for this parameter as we don’t know what fraction of reported landings are discarded at sea.
SelYears: (Optional) Years representing join-points (vertices) at which historical selectivity pattern changes. Vector. Positive real numbers
Slot not used.
AbsSelYears: (Optional) Calendar years corresponding with SelYears (eg 1951, rather than 1), used for plotting only. Vector (of same length as SelYears). Positive real numbers
Slot not used.
L5Lower: (Optional) Lower bound of L5 (use ChooseSelect function to set these). Vector. Non-negative real numbers
Slot not used.
L5Upper: (Optional) Upper bound of L5 (use ChooseSelect function to set these). Vector. Non-negative real numbers
Slot not used.
LFSLower: (Optional) Lower bound of LFS (use ChooseSelect function to set these). Vector. Non-negative real numbers
Slot not used.
LFSUpper: (Optional) Upper bound of LFS (use ChooseSelect function to set these). Vector. Non-negative real numbers
Slot not used.
VmaxLower: (Optional) Lower bound of Vmaxlen (use ChooseSelect function to set these). Vector. Fraction
Slot not used.
VmaxUpper: (Optional) Upper bound of Vmaxlen (use ChooseSelect function to set these). Vector. Fraction
Slot not used.
CurrentYr: The current calendar year (final year) of the historical simulations (eg 2011). Single value. Positive integer.
Specified Value(s): 2015
The most recent fishery data is from 2016.
MPA: (Optional) Matrix specifying spatial closures for historical years.
Slot not used.
The observation model parameters are taken from the Precise_Unbiased model in DLMtool. These parameters could updated after discussion with the yellowfin tuna species experts.
Cobs: Log-normal catch observation error expressed as a coefficient of variation. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.1, 0.2
Borrowed from Precise_Unbiased
Cbiascv: Log-normal coefficient of variation controlling the sampling of bias in catch observations for each simulation. Uniform distribution lower and upper bounds. Non-negative real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
CAA_nsamp: Number of catch-at-age observation per time step. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 150, 300
Borrowed from Precise_Unbiased
CAA_ESS: Effective sample size (independent age draws) of the multinomial catch-at-age observation error model. Uniform distribution lower and upper bounds. Positive integers
Specified Value(s): 50, 100
Borrowed from Precise_Unbiased
CAL_nsamp: Number of catch-at-length observation per time step. Uniform distribution lower and upper bounds. Positive integers
Specified Value(s): 150, 300
Borrowed from Precise_Unbiased
CAL_ESS: Effective sample size (independent length draws) of the multinomial catch-at-length observation error model. Uniform distribution lower and upper bounds. Positive integers
Specified Value(s): 50, 100
Borrowed from Precise_Unbiased
Iobs: Observation error in the relative abundance indices expressed as a coefficient of variation. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1, 0.25
Borrowed from Precise_Unbiased
Ibiascv: Not Used. Log-normal coefficient of variation controlling error in observations of relative abundance index. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1
Borrowed from Precise_Unbiased
Btobs: Log-normal coefficient of variation controlling error in observations of current stock biomass among years. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05, 0.2
Borrowed from Precise_Unbiased
Btbiascv: Uniform-log bounds for sampling persistent bias in current stock biomass. Uniform-log distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.33, 3
Borrowed from Precise_Unbiased
beta: A parameter controlling hyperstability/hyperdepletion where values below 1 lead to hyperstability (an index that decreases slower than true abundance) and values above 1 lead to hyperdepletion (an index that decreases more rapidly than true abundance). Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.67, 1.5
Borrowed from Precise_Unbiased
LenMbiascv: Log-normal coefficient of variation for sampling persistent bias in length at 50 percent maturity. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
Mbiascv: Log-normal coefficient of variation for sampling persistent bias in observed natural mortality rate. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
Kbiascv: Log-normal coefficient of variation for sampling persistent bias in observed growth parameter K. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
t0biascv: Log-normal coefficient of variation for sampling persistent bias in observed t0. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
Linfbiascv: Log-normal coefficient of variation for sampling persistent bias in observed maximum length. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
LFCbiascv: Log-normal coefficient of variation for sampling persistent bias in observed length at first capture. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
LFSbiascv: Log-normal coefficient of variation for sampling persistent bias in length-at-full selection. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05
Borrowed from Precise_Unbiased
FMSYbiascv: Not used. Log-normal coefficient of variation for sampling persistent bias in FMSY. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1
Borrowed from Precise_Unbiased
FMSY_Mbiascv: Log-normal coefficient of variation for sampling persistent bias in FMSY/M. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.25
Borrowed from Precise_Unbiased
BMSY_B0biascv: Log-normal coefficient of variation for sampling persistent bias in BMSY relative to unfished. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1
Borrowed from Precise_Unbiased
Irefbiascv: Log-normal coefficient of variation for sampling persistent bias in relative abundance index at BMSY. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1
Borrowed from Precise_Unbiased
Crefbiascv: Log-normal coefficient of variation for sampling persistent bias in MSY. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1
Borrowed from Precise_Unbiased
Brefbiascv: Log-normal coefficient of variation for sampling persistent bias in BMSY. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1
Borrowed from Precise_Unbiased
Dbiascv: Log-normal coefficient of variation for sampling persistent bias in stock depletion. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.2
Borrowed from Precise_Unbiased
Dobs: Log-normal coefficient of variation controlling error in observations of stock depletion among years. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.02, 0.1
Borrowed from Precise_Unbiased
hbiascv: Log-normal coefficient of variation for sampling persistent bias in steepness. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.1
Borrowed from Precise_Unbiased
Recbiascv: Log-normal coefficient of variation for sampling persistent bias in recent recruitment strength. Uniform distribution lower and upper bounds. Positive real numbers
Specified Value(s): 0.05, 0.1
Borrowed from Precise_Unbiased
Histograms of 48 simulations of inter-annual variability in catch observations (Csd
) and persistent bias in observed catch (Cbias
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
Histograms of 48 simulations of inter-annual variability in depletion observations (Dobs
) and persistent bias in observed depletion (Dbias
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
Histograms of 48 simulations of inter-annual variability in abundance observations (Btobs
) and persistent bias in observed abundance (Btbias
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
Histograms of 48 simulations of inter-annual variability in index observations (Iobs
) and hyper-stability/depletion in observed index (beta
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
Time-series plot of 3 samples of index observation error:
Plot showing an example true abundance index (blue) with 3 samples of index observation error and the hyper-stability/depletion parameter (beta
):
Histograms of 48 simulations of inter-annual variability in index observations (Recsd
) , with vertical colored lines indicating 3 randomly drawn values used in other plots:
Histograms of 48 simulations of catch-at-age effective sample size (CAA_ESS
) and sample size (CAA_nsamp
) and catch-at-length effective (CAL_ESS
) and actual sample size (CAL_nsamp
) with vertical colored lines indicating 3 randomly drawn values:
Histograms of 48 simulations of bias in observed natural mortality (Mbias
), von Bertalanffy growth function parameters (Linfbias
, Kbias
, and t0bias
), length-at-maturity (lenMbias
), and bias in observed length at first capture (LFCbias
) and first length at full capture (LFSbias
) with vertical colored lines indicating 3 randomly drawn values:
Histograms of 48 simulations of bias in observed FMSY/M (FMSY_Mbias
), BMSY/B0 (BMSY_B0bias
), reference index (Irefbias
), reference abundance (Brefbias
) and reference catch (Crefbias
), with vertical colored lines indicating 3 randomly drawn values:
TACFrac: Mean fraction of TAC taken. Uniform distribution lower and upper bounds. Positive real number.
Specified Value(s): 1, 1
Borrowed from Perfect_Imp
TACSD: Log-normal coefficient of variation in the fraction of Total Allowable Catch (TAC) taken. Uniform distribution lower and upper bounds. Non-negative real numbers.
Specified Value(s): 0, 0
Borrowed from Perfect_Imp
TAEFrac: Mean fraction of TAE taken. Uniform distribution lower and upper bounds. Positive real number.
Specified Value(s): 1, 1
Borrowed from Perfect_Imp
TAESD: Log-normal coefficient of variation in the fraction of Total Allowable Effort (TAE) taken. Uniform distribution lower and upper bounds. Non-negative real numbers.
Specified Value(s): 0, 0
Borrowed from Perfect_Imp
SizeLimFrac: The real minimum size that is retained expressed as a fraction of the size. Uniform distribution lower and upper bounds. Positive real number.
Specified Value(s): 1, 1
Borrowed from Perfect_Imp
SizeLimSD: Log-normal coefficient of variation controlling mismatch between a minimum size limit and the real minimum size retained. Uniform distribution lower and upper bounds. Non-negative real numbers.
Specified Value(s): 0, 0
Borrowed from Perfect_Imp
Histograms of 48 simulations of inter-annual variability in TAC implementation error (TACSD
) and persistent bias in TAC implementation (TACFrac
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
Histograms of 48 simulations of inter-annual variability in TAE implementation error (TAESD
) and persistent bias in TAC implementation (TAEFrac
), with vertical colored lines indicating 3 randomly drawn values used in other plots:
Histograms of 48 simulations of inter-annual variability in size limit implementation error (SizeLimSD
) and persistent bias in size limit implementation (SizeLimFrac
), with vertical colored lines indicating 3 randomly drawn values used in other plots: