Yield per
Recruit
(YPR)
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Yield per
Recruit
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Version 2.7.2 (April 2008) |
Core Application |
Yield per Recruit (YPR) is a major revision of earlier implementations of the basic Thompson-Bell model for estimating the expected lifetime yield and biomass from a cohort subjected to varying levels of fishing mortality.
The present version incorporates estimates of life-history parameters such as mean age, mean generation time, reproductive value, expected number of spawnings, reproductive output from first-, second- and multiple time spawners. In addition the user can investigate the resulting age composition of catch and abundance under different levels of fishing mortality. Sensitivity analyses allow the user to investigate the influence of age at entry on the predicted yield and other population attributes.
The user can enter the known coefficients of either a Beverton-Holt or Ricker stock recruitment relationship and perform a Sissenwine-Shepherd analysis for equilibrium estimates of MSY and biomass at MSY.
The user can also conduct sensitivity analyses for any model parameter. Data visualization methods are emphasized to allow exploration of the population consequences of increasing fishing mortality.
FACT input files will be automatically converted to the new input file format.
Gabriel, W.L., M. P. Sissenwine, and W. J. Overholtz. 1989. Analysis of spawning stock biomass per recruit: An example of Georges Bank haddock. North American Journal of Fisheries Management 9:383-391, 1989.
Thompson, W.F. and F.H Bell. 1934. Biological statistics of the Pacific halibut fishery. (2) Effects of changes in intensity upon total yield and yield per unit of gear. International Fisheries Commission Report, No. 8, 1934.
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Version History |
YPR Version 2.7.1 (May 2007)
Fixed a bug where selecting Create a New Case from the File menu caused the GUI to crash.
YPR Version 2.7 (April 2007)
Includes a new grid editing tool with easier data entry and copy/paste abilities.
Ability to save files with spaces in the file name, and use spaces in folder names.
Upgraded version of the plotting package.
YPR Version 2.6.2 (May 2006)
Fixed minor graphics bug which constrained the values that could be entered for recruitment equation coefficients. All constraints have been dropped
May 2003
The age based YPR graphical interface was completely rewritten for this version. In addition to the new style features the plot displays have been improved.
User may specify three weight vectors: Catch Weight, Stock Weight, and Spawning Stock Weight. This may be of value for fast growing species.
The model now allows a user to input parameters for Stock Recruitment equations and perform a Sissenwine-Shepherd analysis.
NOAA Fisheries Toolbox Version 3.1
website last modified November 13, 2009
