CCAMLR

Japanese multidisciplinary survey with a focus on biomass estimation of Antarctic krill will be conducted in CCAMLR Division 58.4.1 during 2018/19. The biomass estimation will be conducted according to the up-to-date CCAMLR standard protocol. The first standardized survey was conducted by CCAMLR in 2000 as the CCAMLR-2000 survey. Quantitative echosounders has evolved since then and a current model is EK80. Though EK80 can transmit both conventional narrowband continuous wave (CW) and new broadband frequency modulation wave (FM), CW will be used for biomass estimation to follow the CCAMLR standard-method. Three-frequency (38, 120 and 200 kHz) krill identification method which is the current CCAMLR standard will be employed in the analysis but utility of 70 kHz data will also be investigated. Measurements of acoustic impedances (mass density and sound-speed contrasts) of krill will also be conducted during the survey. Currently, the compatibility of the output data between EK60 and EK80 has been discussed at ICES WGFAST and this aspect will also be investigated in this survey.

Three surveys of acoustic data from around South Georgia, collected using a four frequency echosounder (38, 70, 120 and 200 kHz), were used to characterise Antarctic krill. Identification of krill targets was carried out using different permutations of two and three-frequency windows. Density was estimated, from identified krill targets, using the 120 kHz data and an acoustic scattering model. A Bland-Altman analysis with a pre-set nominal cut-off of ≤5 gm^-2 bias between methods identified that only the 120-70 kHz (S_v120-70) identification window was comparable with the regularly used 120-38 kHz (S_v120-38) window, and only the 200-120 kHz and 120-70 kHz (S_v120-70 & S_v200-120) identification window was comparable with the regularly used 120-38 and 200-120 kHz  (S_v120-38 & S_v200-120) three-frequency window.

The proposed boundaries of the Weddell Sea MPA (WSMPA) include the significant area of 1.3 million km².  It is shown that the WSMPA boundaries should be revised in compliance with sea-ice conditions for vessel navigation being a fundamental factor for the successful completion of assigned research tasks in designated areas.  

It is shown that the proposals for the establishment of an MPA in the Weddell Sea should be complemented by information on the commercial potential and future rational use for dominant fish species and krill in Subareas 48.5 and 48.6.