DATA 4 Discard Data

[brianlangseth-NOAA]

Issues listed in the data spreadsheet for determining discard information [plus additional edits from Ian on 5 April 2021]

• Total mortality estimates
• Commercial discard mortality rates--we will probably roll over the 2017 values: "Discard mortality rates of 7% for fixed gears and 50% for trawl gears are applied in this assessment." (from page 43)
• Commercial discard rates from WCGOP
• Commercial length comps from WCGOP
• Recreational length comps (decided not to model rec discards explicitly)
• Recreational discard rates and mortality (see Better support for modeling recreational discards RecFIN#2)

[iantaylor-NOAA]

More on commercial discard rates for Lingcod:

• Commercial discard rates can be processed following the approach @chantelwetzel-noaa used for Dover
  • Description is "A single discard rate was calculated by weighting discard rates based on the commercial landings by each sector" (from https://github.com/chantelwetzel-noaa/dover_sole_2021/blob/master/write_up/21f-.Rmd#L34)
  • Code used to combine across sectors https://github.com/chantelwetzel-noaa/dover_sole_2021/blob/master/code/discard_rates_combine.R

Exploration of sector-specific discard rates for Lingcod are in this script, along with code to make figures like those below (also in discards), which are confidential for some other sectors: https://github.com/iantaylor-NOAA/Lingcod_2021/blob/main/R/lingcod_discard_ratios.R

[iantaylor-NOAA]

No total mortality estimates included, but closing issue anyway.