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Bioeconomic Module Data Requirements

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Ricardo Oliveros Ramos edited this page Jun 11, 2026 · 2 revisions

This page describes the data required to parameterise and apply the Economic Module, with emphasis on which inputs come from OSMOSE and which inputs must be provided externally.

For the equations where these quantities are used, see Bioeconomic Module Mathematical Formulation. For the list of parameters, see Bioeconomic Module Parameters. For the estimation workflow, see Bioeconomic Module Calibration.

Overview

The Economic Module links biological outputs from OSMOSE with economic information on prices, costs, profitability and consumer preferences.

The biological inputs describe the state of the simulated populations and the catches produced by the fishery. These inputs usually come from OSMOSE or are derived from OSMOSE outputs. The economic inputs describe market conditions, cost structures and demand assumptions. These inputs generally need to be provided from external data, literature values or user-defined assumptions.

The main data groups are:

  • biological inputs from OSMOSE;
  • fishery and harvest inputs from OSMOSE or from external data;
  • selectivity or catchability inputs;
  • economic observations;
  • parameters taken from the literature or assumed;
  • quantities calculated by the Economic Module.

Inputs from OSMOSE

OSMOSE provides the biological quantities needed to connect population dynamics with the economic formulation.

The main OSMOSE-derived inputs are:

Data item Symbol Resolution Notes
Species identity $i$ Species Defines the species represented in the economic module
Size classes $s$ Species and size class Should match the biological size structure used by OSMOSE
Time steps or years $t$ Time Economic data should be aligned with the OSMOSE temporal resolution or aggregated to years
Population numbers $N_{i,s,t}$ Species, size class and time Number of individuals in each size class
Individual weight $w_{i,s}$ Species and size class Used to convert numbers into biomass; should be expressed in kg
Harvest or catch $H_{i,t}$ or $h_{i,s,t}$ Species, size class and time Can come from OSMOSE fishing outputs if fishing is simulated
Fishing mortality $F_{i,s,t}$ Species, size class and time Can be used when catchability is fitted to fishing mortality

Depending on the OSMOSE outputs available, harvest may be provided as total harvest by species, $H_{i,t}$, or as harvest by species and size class, $h_{i,s,t}$.

If only total harvest is available, the Economic Module can distribute harvest among size classes according to retainment and accessible biomass. If harvest by size class is already available from OSMOSE, it can be used directly.

Inputs derived from OSMOSE outputs

Some quantities may not be direct OSMOSE outputs but can be derived from OSMOSE outputs before applying the Economic Module.

These include:

Derived data item Symbol Derived from Notes
Biomass by size class $w_{i,s}N_{i,s,t}$ Individual weight and population numbers Used to calculate accessible biomass
Accessible biomass $B_{i,t}$ Population numbers, weights and catchability Can be calculated by the Economic Module
Harvest by size class $h_{i,s,t}$ Total harvest and size-specific retainment Can be calculated if not provided directly
Revenue by species or size class $p_{i,s,t}h_{i,s,t}$ Prices and harvest by size class Calculated once prices are provided

Accessible biomass is the part of the population that could potentially be harvested. It is calculated from catchability, individual weights and population numbers.

External economic inputs

The following inputs are not produced by OSMOSE and must be provided from observations, literature values, assumptions or calibration.

Data item Symbol Resolution Notes
Prices per kg $p_{i,s,t}$ Species, size class and time Used to estimate demand parameters and calculate revenue
Profit margins $\pi_{i,t}$ Species and time Used to estimate cost parameters
Cost information $C_{i,t}$ or related data Species and time Optional if profit margins are available
Consumer preferences for size classes $\beta_{i,s}$ Species and size class Estimated or assumed
Consumer preferences for species $\alpha_i$ Species Estimated or assumed
Elasticity of substitution between sizes $\mu_i$ Species Usually taken from the literature or assumed
Elasticity of substitution between species $\sigma$ Model or market level Usually taken from the literature or assumed
Elasticity of demand for fish $\eta$ Model or market level Estimated or assumed
Weight of fish consumption in utility $\gamma$ Model or market level Estimated from expenditure or assumed

Prices should be provided by species, size class and time whenever possible. If prices are only available by species, additional assumptions are needed to distribute prices among size classes.

Profit margins are used in the estimation of the cost function parameters. If profit margin data are not available and the fishery has been operating at or close to open access conditions, the profit margin can be assumed to be zero.

Selectivity and catchability inputs

The module requires catchability or retention by species, size class and time:

$$ q_{i,s,t} $$

This is the proportion of individuals in a size class that are retained in the net. It needs to be between 0 and 1.

Catchability can be provided in different ways:

  • directly, as $q_{i,s,t}$;
  • through a selectivity function;
  • through fishing mortalities;
  • from OSMOSE fishing outputs, if available and compatible with the economic formulation.

Alternatively, one can fit the catchability to fishing mortalities:

$$ F_{i,s,t} = F_{i,t}^{max} , q_{i,s,t} $$

where $F_{i,s,t}$ is the fishing mortality for species $i$ and size class $s$ in year $t$, and $F_{i,t}^{max}$ is the maximum fishing mortality for species $i$ in year $t$.

If catchability is not provided by OSMOSE, it should be defined as an external fishing or gear assumption.

Data pathways

The Economic Module can be applied through different data pathways, depending on which biological and fishery outputs are available from OSMOSE.

Pathway 1: OSMOSE population numbers and external catchability

Use this pathway when OSMOSE provides population numbers by species, size class and time, but accessible biomass has not been calculated.

Required inputs:

  • population numbers from OSMOSE, $N_{i,s,t}$;
  • individual weights, $w_{i,s}$;
  • catchability or retention, $q_{i,s,t}$;
  • total harvest, $H_{i,t}$.

The Economic Module uses these quantities to calculate accessible biomass, $B_{i,t}$, and harvest by size class, $h_{i,s,t}$.

Pathway 2: OSMOSE harvest by size class and calculated accessible biomass

Use this pathway when OSMOSE provides harvest by species, size class and time, and accessible biomass can be calculated from population numbers and catchability.

Required inputs:

  • harvest by size class from OSMOSE, $h_{i,s,t}$;
  • population numbers from OSMOSE, $N_{i,s,t}$;
  • individual weights, $w_{i,s}$;
  • catchability or retention, $q_{i,s,t}$.

The Economic Module uses harvest by size class directly and calculates accessible biomass if needed.

Pathway 3: externally provided harvest and accessible biomass

Use this pathway when catchability and population numbers are not available, but harvest and accessible biomass have already been calculated elsewhere.

Required inputs:

  • harvest by size class, $h_{i,s,t}$;
  • accessible biomass, $B_{i,t}$.

This pathway bypasses the need to calculate accessible biomass from OSMOSE population numbers and catchability.

Data used for cost parameter estimation

Cost parameter estimation requires:

  • catch or harvest;
  • accessible biomass;
  • profitability data.

The following parameters are estimated from these data:

  • baseline costs, $c_{i,0}$;
  • stock elasticity, $\chi_i$;
  • time trend on fishing costs, $\tau_i$.

The biological and fishery inputs may come from OSMOSE, while profitability data must be provided externally.

For details, see Bioeconomic Module Calibration.

Data used for demand parameter estimation

Demand parameter estimation requires:

  • prices per kg, $p_{i,s,t}$;
  • harvest by species, size class and time, $h_{i,s,t}$;
  • assumed or literature-based substitution elasticities.

Harvest by species and size class can come from OSMOSE or be derived from OSMOSE outputs. Prices and elasticity assumptions are external economic inputs.

Species and size-class preferences are estimated using the inverse demand function, assuming market equilibrium.

The following parameters are estimated from these data:

  • size-class preferences, $\beta_{i,s}$;
  • species preferences, $\alpha_i$;
  • the weight of fish consumption in total utility, $\gamma$;
  • the elasticity of demand for fish, $\eta$.

The elasticities of substitution between size classes, $\mu_i$, and between species, $\sigma$, are either taken from the literature or assumed.

Minimum data checklist

The following information is needed for a complete parameterisation.

Data item Symbol Source Resolution Notes
Species identity $i$ OSMOSE Species Must match the species represented in the economic module
Size classes $s$ OSMOSE Species and size class Must match OSMOSE size structure or an agreed aggregation
Time steps or years $t$ OSMOSE and external data Time Biological and economic data must be aligned
Population numbers $N_{i,s,t}$ OSMOSE Species, size class and time Used to calculate accessible biomass
Individual weights $w_{i,s}$ OSMOSE or derived Species and size class In kg
Harvest by size class $h_{i,s,t}$ OSMOSE or derived Species, size class and time Can be calculated or provided directly
Total harvest $H_{i,t}$ OSMOSE or external data Species and time Used when harvest by size class is not available
Fishing mortality $F_{i,s,t}$ OSMOSE or external data Species, size class and time Optional, used to fit catchability
Catchability or retention $q_{i,s,t}$ External or derived Species, size class and time Must be between 0 and 1
Accessible biomass $B_{i,t}$ Calculated or external Species and time Can be calculated from OSMOSE outputs and catchability
Prices per kg $p_{i,s,t}$ External economic data Species, size class and time Used for revenue and demand estimation
Profit margins $\pi_{i,t}$ External economic data Species and time If unavailable, may be set to zero under open access assumptions

Optional or assumed information

The following information may be taken from the literature or assumed:

Data item Symbol Notes
Elasticity of substitution between sizes $\mu_i$ Higher values indicate easier substitutability between size classes
Elasticity of substitution between species $\sigma$ Should be lower than $\mu_i$ since sizes are better substitutes than species
Open access profit margin assumption $\pi_{i,t}=0$ Used when profit margins are unavailable and the fishery is close to open access
Baseline cost trend assumptions $\tau_i$ Can represent increasing fuel prices or technological advancement
Consumer preferences for size classes $\beta_{i,s}$ Estimated when data are available, otherwise assumed
Consumer preferences for species $\alpha_i$ Estimated when data are available, otherwise assumed

Data dimensions

The data should be organised consistently across:

  • species ($i$);
  • size class ($s$);
  • year or time step ($t$).

The economic data should match the biological data used by OSMOSE or derived from OSMOSE outputs. In particular, species names, size classes, units and time steps should be harmonised before parameterisation.

If OSMOSE outputs are produced at a finer temporal resolution than the economic data, the biological and fishery outputs may need to be aggregated to the temporal resolution of the economic observations.

Common data issues

Common issues include:

  • missing profit margin data;
  • prices available by species but not by size class;
  • harvest available as total catch but not by size class;
  • catchability or retention not directly observed;
  • mismatch between OSMOSE size classes and market size categories;
  • mismatch between OSMOSE time steps and annual economic data;
  • inconsistent biomass or weight units;
  • missing or uncertain substitution elasticities.

When some of these data are unavailable, assumptions or simplified parameterisations may be needed. These assumptions should be documented clearly in the corresponding case study.

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