Stock Status Update for Arrowtooth Flounder in 2024

Arrowtooth Flounder (Atheresthes stomias) stock status on the West Coast of British Columbia was last assessed using data from 1996-2021 (DFO 2023; Grandin et al. 2024). In the last assessment (reviewed in 2022; the '2022 stock assessment'), the stock was estimated slightly below the Upper Stock Reference (USR) in the base model and close to the Limit Reference Point (LRP) under one sensitivity model with higher recruitment variation. The model also showed declining estimated spawning stock biomass, declining survey indices, and declining estimated recruitment. Due to these issues, a two-year update on the stock was requested by the Groundfish Management Unit (GMU). This two-year span was chosen since the biennial survey indexes included in the model would each have one new year of data. The 2022 stock assessment estimated a median stock size at the beginning of 2022 (or end of 2021) of 67.95 kilotonnes (kt) with a credible interval (Cl) of 56.14-83.83 kt. When divided by the estimated unfished biomass (Bo), the median relative biomass for 2022 was estimated to be 0.37 with a Cl of 0.26--0.51. The estimated median relative biomass for 2011, was estimated to be 0.77 with a Cl of 0.53-1.09. The estimated biomass declined each year from 2011-2021. This Science Response results from the regional peer review on October 2, 2024 on the Update Stock Assessment for Arrowtooth Flounder (Atheresthes stomias) in British Columbia.