MP32 powerramp candidate

MP32: All-index Powerramp Candidate

Status: sensitivity case in the current jmMSE analysis. MP32 preserves the earlier +20 annual-increase specification and has not been adopted. This page is part of SC14-MSE-2026-RC1 and uses the common 500-draw refinement.

1 Identity

Component	Current definition
Name in the `jmMSE` analysis	`tun32`, labelled MP32
Stock/index indicator	`cpues.ind`
Indices	`Chile_AcousN`, `Chile_CPUE`, `Peru_Artis`, `Peru_Ind`, `Offshore_CPUE`
Reference years	2019-2023
Recent-data window	3 years
How the indices are combined	Mean (`combine = "mean"`, `metric = "mean"`)
Harvest control rule	Power ramp (`powerramp.hcr`)
Output	Catch
Catch allocation	Split among fisheries using their average catch proportions over the last five years (`split.is`)

2 Harvest control rule parameters

Parameter	Value
Minimum catch, `min`	270
Limit metric, `lim`	0.1
Trigger metric	1.640625
Target catch	1500
Initial catch for constraints	1385
Maximum annual decrease multiplier, `dlow`	0.85
Maximum annual increase multiplier, `dupp`	1.20

3 Rule

Let $I_t$ be the annual mean of the standardized index information and

\[ x_t = \frac{I_t-0.1}{1.640625-0.1}. \]

Before applying the annual change limit, the current power-ramp rule calculates the catch recommendation as

\[ C_t^* = \begin{cases} 270, & I_t \le 0.1,\\ 270 + (1500-270)x_t^{2.5}, & 0.1 < I_t < 1.640625,\\ 1500(0.2+0.8x_t)^{0.6}, & I_t \ge 1.640625. \end{cases} \]

Unlike a capped hockeystick, the upper branch continues to rise above the trigger. The annual change rule then prevents the result from falling below 85% or rising above 120% of the previous recommendation. For the first application year, the reference value is 1385.

4 What the current analysis shows

The current analysis retains MP29 and MP32 as annual-limit sensitivities to focal MP43 and MP44. MP32’s realized mean dynamic Kobe-green probability was 0.6026 over 2041–2050. The complete reference and alternative-OM comparison is reported in the SC14 package.

Primary sources: model_tune.R, model_robustness.R, and the July WUR presentation.

5 Annual application requirements still to resolve

authoritative provider and annual cutoff for each index;
precise index standardization performed by cpues.ind and the software version used;
treatment of missing or revised indices;
catch units and rounding;
approved catch-allocation update rule; and
exceptional-circumstances review and decision process.

--- title: "MP32 powerramp candidate" --- {{< include ../_includes/sprfmo-banner.qmd >}} <div class="paper-title">MP32: All-index Powerramp Candidate</div> ::: {.status-note} **Status:** sensitivity case in the current `jmMSE` analysis. MP32 preserves the earlier +20 annual-increase specification and has not been adopted. This page is part of `SC14-MSE-2026-RC1` and uses the common 500-draw refinement. ::: ## Identity | Component | Current definition | |---|---| | Name in the `jmMSE` analysis | `tun32`, labelled MP32 | | Stock/index indicator | `cpues.ind` | | Indices | `Chile_AcousN`, `Chile_CPUE`, `Peru_Artis`, `Peru_Ind`, `Offshore_CPUE` | | Reference years | 2019-2023 | | Recent-data window | 3 years | | How the indices are combined | Mean (`combine = "mean"`, `metric = "mean"`) | | Harvest control rule | Power ramp (`powerramp.hcr`) | | Output | Catch | | Catch allocation | Split among fisheries using their average catch proportions over the last five years (`split.is`) | ## Harvest control rule parameters | Parameter | Value | |---|---:| | Minimum catch, `min` | 270 | | Limit metric, `lim` | 0.1 | | Trigger metric | 1.640625 | | Target catch | 1500 | | Initial catch for constraints | 1385 | | Maximum annual decrease multiplier, `dlow` | 0.85 | | Maximum annual increase multiplier, `dupp` | 1.20 | ## Rule Let $I_t$ be the annual mean of the standardized index information and $$ x_t = \frac{I_t-0.1}{1.640625-0.1}. $$ Before applying the annual change limit, the current power-ramp rule calculates the catch recommendation as $$ C_t^* = \begin{cases} 270, & I_t \le 0.1,\\ 270 + (1500-270)x_t^{2.5}, & 0.1 < I_t < 1.640625,\\ 1500(0.2+0.8x_t)^{0.6}, & I_t \ge 1.640625. \end{cases} $$ Unlike a capped hockeystick, the upper branch continues to rise above the trigger. The annual change rule then prevents the result from falling below 85% or rising above 120% of the previous recommendation. For the first application year, the reference value is 1385. ## What the current analysis shows The current analysis retains MP29 and MP32 as annual-limit sensitivities to focal MP43 and MP44. MP32's realized mean dynamic Kobe-green probability was 0.6026 over 2041--2050. The complete reference and alternative-OM comparison is reported in the SC14 package. Primary sources: [`model_tune.R`](https://github.com/SPRFMO/jmMSE/blob/main/model_tune.R), [`model_robustness.R`](https://github.com/SPRFMO/jmMSE/blob/main/model_robustness.R), and the [July WUR presentation](../evidence/presentation_20260725.pdf). ## Annual application requirements still to resolve - authoritative provider and annual cutoff for each index; - precise index standardization performed by `cpues.ind` and the software version used; - treatment of missing or revised indices; - catch units and rounding; - approved catch-allocation update rule; and - exceptional-circumstances review and decision process.