Research Document - 2012/036
Bayesian Surplus Production modelling for American Plaice (Hippoglossoides platessoides)
By J.A. Bailey
Using a Bayesian modelling approach, a Schaefer surplus-production (SP) curve was fit to commercial landings and indices of population biomass of each of three populations of American Plaice (Hippoglossoides platessoides). The curve was then projected forward under various scenarios using Bayesian probability modeling in order to assess expected population trajectories over a biologically reasonable time frame for this species (48 years).
In order to examine the possibility that productivity may have changed between 1960-2009, several models were examined for each stock which divided the time series into 1 to 3 periods of productivity.
The paper describes the process and methodology used to fit a Bayesian Surplus Production Model to American Plaice biomass. Results indicated that such models could be useful in the Recovery Potential Assessment of American plaice. The results were consistent with stock assessments of these populations and showed that all three remain well below the estimated biomass level at the beginning of their respective time series.
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