Relative abundance of skipjack tuna for the purse seine fishery operating in the Philippines Moro Gulf (Region 12) and High Seas Pocket #1

Port sampling data were used to estimate effort, catch, catch per unit effort (CPUE), standardized CPUE and species composition from the purse seine fishery operating in the southern Philippines (Region 12, SOCCSKSARGEN) and High Seas Pocket #1 from 2005 to 2018. A relative abundance index was produced as a quarterly standardized CPUE index from 2005 to 2018 for use in the 2019 WCPFC skipjack tuna assessment. Standardized CPUE was estimated by Generalized Linear Models (GLMs) by removing effects due to vessel and fishing ground (area). The current index predicted quarterly CPUE with a YR:QTR, Area (fishing ground) and Vessel effects. A combined YR:QTR effect was estimated to be consistent with other fishery CPUE standardization methods used in the assessment. Effort by many vessels consisted of only a few trips and data were filtered for active vessels which had conducted 20 or more trips and resulted in a subset of 54 vessels. There were 18 Area designations in the database; however, Area was relatively non-informative in the model as fishing trips were dominated by 4 areas. 2019 NMFS (National Marine Fisheries Service) PIFSC (Pacific Islands Fisheries Science Center) Submitted https://doi.org/10.25923/8pxa-7s16 Public Domain 1862