Stratified_CPUE: Function to estimate Biomass or CPUE from stratified-random...
In rooperc4/GLMGAMRF: Package fits GLM, GAM and Random Forest models to survey data

Description Usage Arguments Examples

This function estimates a design-based survey estimator for a stratified-random survey design. Either a population biomass or CPUE can be output. At the moment the function is set up to incorporate the Gulf of Alaska or the Aleutian Islands bottom trawl survey. It requires CPUE data, Strata designations and total area (in km^2). It can also be used to calculate an estimate for only the trawlable portion of the strata.

1 2	Stratified_CPUE(Catch, Year, Strata, Strata_area, Region = "GOA", Proportion_trawlable = 1, method = "Biomass")

`Catch`	Catch-per-unit-of-effort for each bottom trawl haul
`Year`	Survey year
`Strata`	Strata designation for each haul
`Strata_area`	Area of the strata in km2 where each haul occurs
`Region`	Either "GOA" (the default) or "AI"
`Proportion_trawlable`	The proportion of the strata that can be sampled by the survey trawl (default is 1)
`method`	Either "Biomass" or "CPUE"

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design.index<-Stratified_CPUE(Design.data$juvenile_POP_CPUE,Design.data$year,Design.data$STRATUM,Design.data$AREA_KM2,"GOA",1, "CPUE")
design.index<-Stratified_CPUE(Design.data$juvenile_POP_CPUE,Design.data$year,Design.data$STRATUM,Design.data$AREA_KM2,"AI",Design.data$Trawlable, "Biomass")