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Line Art Drawing of a FishAge Structured Projection Model


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Version 4.3.0  (April 2018)

Core Application


The Age Structured Projection Model (AGEPRO) is a projection model for an age-structured fish stock harvested by one or more fleets. AGEPRO was designed to evaluate the probable effects of applying alternative harvest strategies to a fish stock under alternative hypotheses about its stock-recruitment relationship. Uncertainty in the initial stock size at age at the start of the projection time horizon is also incorporated into the model.

AGEPRO interfaces directly with VPA/ADAPT  or ASAP assessment models. It can use bootstrapped or Markov Chain Monte Carlo estimates of initial population size derived from VPA/ADAPT or ASAP or from any age-structured model. AGEPRO uses Monte Carlo simulation to evaluate the probabilities of achieving targets for fishing mortality or stock size, to calculate the probabilities of exceeding biological reference point thresholds, and to calculate the expected future age structure of the and the fishery landings.

The latest version of AGEPRO allows the user to incorporate uncertainty in weights at age, natural mortality, maturity, fishery selectivity, and discard fraction. Additional features include the capacity to calculate annual catch limits with user-specified probabilities of exceeding an overfishing level and the capability to search for rebuilding strategies that achieve user-specified outcomes.

The AGEPRO calculation engine is written in C. It was developed by Dr. Jon Brodziak of NMFS Pacific Islands Fisheries Science Center with contributions by Dr. Paul Rago, NMFS NEFSC and others. The new graphical user interface has been written in C#.


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Brodziak, J., P. Rago, and R. Conser. 1998. A general approach for making short-term stochastic projections from an age-structured fisheries assessment model. In F. Funk, T. Quinn II, J. Heifetz, J. Ianelli, J. Powers, J. Schweigert, P. Sullivan, and C.-I. Zhang (Eds.), Proceedings of the International Symposium on Fishery Stock Assessment Models for the 21st Century. Alaska Sea Grant College Program, Univ. of Alaska, Fairbanks.


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Version History


AGEPRO Version 4.2.2 (September 2013) Ability to include uncertainty in weights at age, natural mortality, maturity, fishery selectivity, and discard fraction added. Search algorithm to find Frebuild added. Calculation engine completely re-written in C.

AGEPRO Version 3.3.3  (May 27, 2009)  - This version fixes a GUI bug in extracting data from the output report when the user has not requested threshold probabilities.

AGEPRO Version 3.3.2  (April 8, 2009)  - This is a Visual Studio 2008 update of the AGEPRO GUI.  Also Jon Brodziak has made a major change to the calculation engine:  There are now 19 Recruitment relationships available, includes four new recruitment prediction models that allow the user to
use up to three covariates for predicting recruitment.

The new recruitment models are:
   *      Linear recruits per spawning biomass predictor with normal error
   *      Loglinear recruits per spawning biomass predictor with lognormal error
   *      Linear recruitment predictor with normal error
   *      Loglinear recruitment predictor with lognormal error

AgePro Includes a model-averaging feature that allows two or more models to be
used to predict recruitment in any year. Model probabililities are used to
specify the sampling frequency of selected recruitment models in each year.
The recruitment models are randomly selected for each simulation in the
projection according to the specified model probabilities. The model-averaging
feature allows one to account for model selection uncertainty in the recruitment
predictions. Model-averaging also provides the option of combining one or more
environmental covariates to predict recruitment in the short term (1-2 yrs)
along with one or more models for medium term projections (3-5 yrs)

AGEPRO Version 3.2.2  (September 2008)

AGEPRO Version 3.1.3 (January 2006)

  • The graphical interface has been substantially revised for version 3.1.

  • User may now specify minimum and maximum values for fishing mortality over the projection horizon.  

  • User may now specify all weights at age as time varying.


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Older Version Changes 


For older changes please see the AGEPRO documentation, or contact User Support.


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