Chapter 11 Next steps

  • Run log likelihood profiles on Female Trawl selectivity parameters. Profiles are very sporadic, when I force males and females to have the same selectivity it does produce sensible answers selectivity curves.

  • Apply the Dirichlet-Multinomial likelihood for compositional data

  • Start model 1990

  • Generate reference points and ABCs

Simulation Scenarios

  • What effect loosing early time-periods has on the assessment advice. The spatial models started much later in the time-series than when significant exploitation occured, which is a common issue with spatial models due to historical data not haveing spatial resolution to be used. This early period coincides with the largest removals in the time-series which is thought to be valuable to observe for observering contrast and helping estimate stock production (Hilborn 1979) this claim is actually countered by Magnusson and Hilborn (2007).

  • What bias can we expect when we assume a closed population when in fact there is emigration outside of the stock boundary

  • Consequence in assuming a three region model when in fact there is five regions based on the Regression break points.

  • Spatial recruitment process and reference point consequences. Time-varying recruit devs by region vs time-varying recruitment deviations constant across

  • age-varying movement? spasm paper to reference time-vs age varying movement.

References

Hilborn, Ray. 1979. “Comparison of Fisheries Control Systems That Utilize Catch and Effort Data.” Journal of the Fisheries Board of Canada 36 (12): 1477–89.
Magnusson, Arni, and Ray Hilborn. 2007. “What Makes Fisheries Data Informative?” Fish and Fisheries 8 (4): 337–58.