Running log of how the state and federal statistical catch-at-age models differ from one another:
The federal assessment uses survey weight-at-age exclusively to fit to catch and effort indices (Hanselman et al. 2018). However, because discarding is permitted in the state fishery, there are large differences in survey and fishery weight-at-age, especially at younger ages. Consequently, fishery weight-at-age was fit to landed catch biomass, whereas survey weight-atage was used to estimate exploitable biomass, spawning biomass, and other quantities of interest in the model.
The state assessments incorporates discards in the estimates of fishing mortality.
The ABC calculation and BRPs for the state model uses the geometric mean to dampen the effects of anomalously high recruitment events. The feds use the arithmetic mean.
Running log of how the state and federal statistical catch-at-age models differ from one another: