In pbs-assess/gfsynopsis: Data Synopsis Reports for PBS Groundfish

International Pacific Halibut Commission survey updates {#app:iphc}

The methods for calculating the International Pacific Halibut Commission (IPHC) design-based index remain unchanged from those described in @anderson2019synopsis and @synopsis2022, except for the following:

1. Species identification has improved over time for some species, therefore data points have been omitted for species where zero counts early in the time series are likely the result of improved species identification. Big Skate and Longnose Skate were both explicitly identified starting in 1998, while the more rarely caught Aleutian Skate and Sandpaper Skate only appear in the data from 2006 onwards. For example, the average catch rate of 'Unidentified Skates' was almost 1 fish per effective skate from 1995--1999. See HG predator analysis vignette. Similarly Shortspine Thornyhead only appears in the data in 1998 and was likely classified under 'Unidentified Thornyhead (idiot)' previously.

2. As occurred in 2021, in 2022 only a subsample of stations off the WCVI were surveyed. This may affect the determination of whether or not Series AB [@anderson2019synopsis Appendix G] can be considered representative of the full coast and is one reason why a model-based index (Appendix \@ref(app:stitching)) may be preferable.

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pbs-assess/gfsynopsis documentation built on March 26, 2024, 7:30 p.m.