Standardizing CPUE of Japanese commercial dip-net fishery targeting spawners of chub mackerel in the Northwest Pacific

In this document, we provide the summary of the CPUE standardization of Japanese commercial dip-net fishery for Pacific chub mackerel following the “CPUE Standardization Protocol for Chub Mackerel”. The year trend of the spawning stock biomass (SSB) was derived from standardized CPUE, by applying the catch-and-effort data of the dip-net fishery targeting spawners of chub mackerel to the delta GLM. Since we found no serious problems in the standardization, we recommend this SSB index to be utilized in the Technical Working Group for the Chub Mackerel Stock Assessment.