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Modules Bioeconomic Module
The Economic Module links OSMOSE biological outputs to economic indicators of fishing and fish consumption. It is designed to evaluate how changes in abundance, size structure, harvest and selectivity can affect harvesting costs, market prices, revenues, profits and welfare-related indicators.
This module is particularly useful when the economic value of a fishery depends not only on total catch, but also on the species and size composition of the catch. For example, a scenario that changes the size structure of a population may also change the accessible biomass, the cost of fishing, the market value of landings, and the welfare consequences of different harvest strategies.
The Economic Module represents the interaction between biological dynamics, fishing activity and market demand. It combines three main processes:
- fishing costs, which depend on harvest and accessible biomass;
- consumer demand, which depends on preferences for species and size classes;
- economic outcomes, including prices, revenues, costs, profits and welfare-related quantities.
The module can be used to analyse historical simulations, compare management scenarios, or explore how assumptions about markets and consumer preferences influence the economic interpretation of OSMOSE outputs.
OSMOSE provides the biological information needed by the Economic Module. Depending on the configuration and the level of aggregation used, this may include abundance, biomass, individual weight, harvest, species identity, size class and time step.
The Economic Module uses these biological quantities together with economic parameters or observations. It can then estimate or calculate indicators such as accessible biomass, harvesting costs, revenues, prices and profits.
In this sense, the Economic Module acts as a bridge between the ecological dynamics simulated by OSMOSE and the economic consequences of fishing.
Accessible biomass is the part of the population that can be harvested by a given fishing process. It depends on the abundance of fish, their individual weight and the probability that individuals of a given size are retained by the fishing gear.
Fishing costs increase with harvest and decrease when accessible biomass is higher. This means that fishing becomes more costly when fish are less available, less accessible, or less efficiently retained by the fishing process.
See Bioeconomic Module Concepts and Assumptions and Bioeconomic Module Mathematical Formulation for the assumptions and equations used to represent accessible biomass and harvesting costs.
Consumers may have preferences for particular species or size classes. The Economic Module represents these preferences and allows substitution among species and among size classes.
This means that the price of a given catch component can depend on its own quantity, the availability of substitute products, and the relative preferences of consumers. The demand component is therefore useful when changes in size composition or species composition are expected to affect market value.
See Bioeconomic Module Concepts and Assumptions and Bioeconomic Module Mathematical Formulation for the demand assumptions and inverse demand equations.
The module calculates revenue from the value of harvested biomass and subtracts harvesting costs to estimate profit. These indicators can be produced by species, size class, time step, or at more aggregated levels, depending on the available inputs and the intended analysis.
See Bioeconomic Module Scenarios and Outputs for the main indicators produced by the module.
The module can also be used in a welfare perspective. In this case, the objective is not only to calculate private profit, but also to evaluate the benefits of fish consumption relative to the costs of extraction.
This framework can be used to compare alternative harvest strategies, selectivity patterns or management scenarios.
See Bioeconomic Module Mathematical Formulation for the welfare objective and Bioeconomic Module Scenarios and Outputs for example applications.
The Economic Module can be used to explore questions such as:
- How do changes in stock abundance affect harvesting costs?
- How does size-selective fishing affect revenue and profit?
- What are the economic consequences of shifts in population size structure?
- How sensitive are prices and profits to consumer preferences for size classes?
- How do alternative harvest or selectivity scenarios compare economically?
- What happens if baseline fishing costs increase or decrease over time?
- How do biological and economic outcomes differ across management scenarios?
The module requires biological information from OSMOSE and economic information from observations, assumptions or calibration.
Typical biological inputs include:
- abundance or biomass by species, size class and time step;
- individual weight by species and size class;
- harvest or catch by species, size class and time step;
- selectivity, retention or accessible biomass.
Typical economic inputs include:
- prices by species and size class;
- profit margins or cost information;
- consumer preferences for species and size classes;
- substitution elasticities;
- cost parameters or assumptions.
Typical outputs include:
- accessible biomass;
- total revenue;
- total harvesting costs;
- profit;
- profit margin;
- prices;
- welfare-related indicators.
See Bioeconomic Module Data Requirements for a detailed list of required and optional inputs, and Bioeconomic Module Parameters for a description of model parameters.
The Economic Module documentation is organised into specialised pages:
- Bioeconomic Module Concepts and Assumptions
- Bioeconomic Module Mathematical Formulation
- Bioeconomic Module Parameters
- Bioeconomic Module Data Requirements
- Bioeconomic Module Calibration and Validation-and-Validation
- Bioeconomic Module Scenarios and Outputs
- Bioeconomic Module Examples
New users should start with this page and then read Bioeconomic Module Concepts and Assumptions.
Users implementing or reviewing the equations should continue with Bioeconomic Module Mathematical Formulation and Bioeconomic Module Parameters.
Users preparing a case study should read Bioeconomic Module Data Requirements, Bioeconomic Module Calibration and Validation-and-Validation and Bioeconomic Module Scenarios and Outputs.
Users looking for practical guidance should consult Bioeconomic Module Examples.