4 Overview of Example Objects
openMSE includes a number of built-in objects that can be used for testing and demonstration. These objects span all four subcomponent types, Stock, Fleet, Obs, and Imp, along with a set of example OM objects that combine them in configurations of increasing complexity.
The objects are intended for demonstration and testing purposes only. The biological and exploitation values should not be interpreted as representing real stock assessments or used to inform management advice.
?sec-buildexamples walks through how each object is constructed step by step.
4.1 Stock Objects
Three Stock objects are provided, representing species with contrasting life histories and model configurations. See Section 12.1 for full construction details.
| Object | Common name | Key characteristics |
|---|---|---|
AlbacoreExStock |
Albacore tuna | Long-lived, slow-growing, low \(M\), low recruitment variability, 2-area |
ButterfishExStock |
Butterfish | Short-lived, fast-growing, high \(M\), high recruitment variability, 2-area |
SeasonalSpatialExStock |
Reef fish | Short-lived, monthly time steps, seasonal recruitment pulse, 3-area ontogenetic movement |
4.2 Fleet Objects
Two Fleet objects are provided, representing gear types with contrasting selectivity patterns. See Section 12.2 for full construction details.
| Object | Selectivity type | Key characteristics |
|---|---|---|
AsympExFleet |
Asymptotic | Logistic selectivity pattern; effort builds gradually to a plateau |
DomeExFleet |
Dome-shaped | Reduced selectivity at largest sizes; slower effort build-up |
4.3 Obs Objects
Five Obs objects are provided, representing monitoring programs of increasing data richness. See Section 12.3 for full construction details.
| Object | Data types |
|---|---|
CommercialFleetObs |
Landings, discards, effort, CPUE |
CatchAndSurveyObs |
Landings, survey index |
AgeStructuredObs |
Landings, discards, survey index, age compositions (landings and discards) |
LengthStructuredObs |
Landings, discards, survey index, length compositions (landings and discards) |
DataRichObs |
Landings, discards, effort, CPUE, survey index, age and length compositions (landings and discards) |
4.4 Imp Objects
The Imp class is currently a placeholder and is not yet implemented. Example Imp objects will be added in the future.
4.5 OM Objects
Five pre-assembled OM objects combine the example stocks, fleets, and observation programs in configurations of increasing complexity. All are initialised with nSim = 8, nYear = 20, and pYear = 30. See Section 12.5 for full construction details.
| Object | Stocks | Fleets per stock | Obs program(s) | Notes |
|---|---|---|---|---|
SingleStockOM |
AlbacoreExStock |
AsympExFleet |
AgeStructuredObs |
|
TwoFleetOM |
AlbacoreExStock |
AsympExFleet, DomeExFleet
|
AgeStructuredObs, CatchAndSurveyObs
|
|
MultiStockOM |
AlbacoreExStock, ButterfishExStock
|
AsympExFleet, DomeExFleet
|
Albacore: AgeStructuredObs, CommercialFleetObs; Butterfish: CatchAndSurveyObs, LengthStructuredObs
|
|
ComplexOM |
AlbacoreExStock, ButterfishExStock (complex) |
AsympExFleet |
AgeStructuredObs |
Stock complex |
SeasonalSpatialOM |
SeasonalSpatialExStock |
DomeExFleet |
CommercialFleetObs |
Monthly seasons, 3-area spatial model |
ComplexOM groups both stocks into a single stock complex (StockComplex), meaning fishery data and management advice are handled at the complex level. See Chapter 19 for more details on stock complexes.
SeasonalSpatialOM uses Seasons = 12 to match the monthly age structure of SeasonalSpatialExStock. It is an example OM with sub-annual time steps and a multi-area ontogenetic spatial model.