Acoustic biomass surveys of orange roughy (Hoplostethus atlanticus) in ORH 3B North Chatham Rise spawning grounds, 4–8 July 2021, on FV Amaltal Apollo. Surveys were undertaken on Morgue and Graveyard hills in NWCR and on the Rekohu aggregation in ESCR. The survey was prematurely curtailed due to vessel engine failure. Ancillary biomass estimates for Rekohu and Spawn Plume aggregations were derived from hull-mounted echosounder snapshots undertaken by FV Amaltal Mariner and FV San Waitaki.