Results of the krill and oceanographic survey under the NEWREP-A in the Antarctic in 2018/19
Atsushi Wada, Toshihiro Mogoe, Keigo Kasahara, Chikamasa Ohkoshi, Yasuaki Sasaki and Tsutomu Tamura
The krill and oceanographic surveys were conducted in the Antarctic Area III-E and IV during the 2018/19 austral summer season as part of fourth dedicated sighting survey of the New Scientific Whale Research Program in the Antarctic Ocean (NEWREP-A). These surveys, which were conducted by two research vessels Yushin Maru No. 2 (YS2) and Kaiyo Maru No. 7 (KY7), are associated with the main objective II of NEWREP-A. The krill survey was conducted along the zig-zag tracklines designed for the whale sighting survey. Acoustic data using quantitative echosounders EK80 (YS2) and EK60 (KY7) were recorded continuously for total 72 days and 7,195n.miles. Net sampling using a small ring net (YS2 and KY7) and an Issak-Kid Midwater Trawl (IKMT) (KY7) was carried out to identify species and size composition of plankton echo signs at 54 stations and 22 stations respectively. Oceanographic observations were also conducted at 144 stations using a Conductivity-Temperature-Depth profiler (CTD) and seawater sampling occurred at 16 stations. Calibration among EK80 and EK60 quantitative echosounders, and simultaneous samplings between small ring net and IKMT were also conducted. Krill and oceanographic data are currently being examined, and results will be reported in related CCAMLR working groups.