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/ADAPTor ASAP
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#.
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.
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.
Version 4.2.2 (September 2013) – Ability to include
weights at age, natural mortality, maturity, fishery selectivity, and
fraction added. Search algorithm to find Frebuild added. Calculation
completely re-written in C.
2009) - This version fixes a GUI
bug in extracting data from the output report when the user has not
requested threshold probabilities.
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
The new recruitment models are:
recruits per spawning biomass predictor with normal error
Loglinear recruits per spawning biomass predictor with lognormal error
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 3.1.3
graphical interface has been substantially revised for version 3.1.
may now specify minimum and maximum values for fishing
mortality over the projection horizon.
may now specify
all weights at age as time varying.