The pre-exploitation krill biomass estimates, B0, is essential for generating the Precautionary Catch Limit (PCL) for sound science-based krill fishery management. In 2019, a multi-member large-scale synoptic acoustic survey was conducted to provide krill biomass estimates for Area 48, whilst various mesoscale surveys were also conducted in Subarea 48.1. Krill biomass estimates for the four US AMLR strata has been provided by WG-ASAM e-group during the 2021 intersessional period. However, krill biomass estimates for the remaining area in Subarea 48.1 as required by the Scientific Committee has not been provided yet. To facilitate the development of the new management approach, here we provide the krill biomass estimates in Subarea 48.1 based on the up-to-date available acoustic surveys.