Revised outline of the dedicated krill survey for CCAMLR Division 58.4.1 during 2018/19 season by the Japanese survey vessel, Kaiyo-maru

A dedicated krill survey for CCAMLR Division 58.4.1 during 2018/19 season will be conducted by Japanese research vessel, Kaiyo-maru. No krill biomass has been estimated in the Division since Australia carried out BROKE in 1996. There are two main objectives of our survey: (1) estimation of krill biomass to update B(0) in the area and (2) oceanographic observations in the area to detect long term changes if any. The krill survey (echosounder–EK80 and RMT) and subsequent biomass estimation will follow the CCAMLR standard protocol. Utility of 70 kHz in addition to 3 standard frequencies (38, 120 and 200 kHz) for biomass estimation will be considered using obtained data. Broadband echosounder measurements of length and orientation of Antarctic krill will also be conducted. An initial plan of the survey was presented to SG-ASAM-17 and WG-EMM-17 as SG-ASAM-17/01 and WG-EMM-17/05, respectively. This paper provides a revised outline of the survey while detailed acoustic survey methods are presented to this meeting in separate papers (Abe et al., 2018; Amakasu et al. 2018). The finalized plan will be submitted to WG-EMM-18.