Zooplankton monitoring using a twin NORPAC net during the 59th Japanese Antarctic Research Expedition in austral summer 2017-2018

As part of the monitoring program of the Japanese Antarctic Research Expedition (JARE), zooplankton sampling using a NORPAC (NORth PACific) standard net has been routinely carried out since JARE-14 (1972/73 season) to estimate the long-term trends of abundance, species composition and their temporal/spatial variation in the uppermost 150 m of the Indian Ocean sector of the Southern Ocean. Two separate monitoring surveys were completed during JARE-59 (December 2017 to March 2018). The icebreaker Shirase has a fixed schedule and route, travel down longitude 110E each December and return along 150E each March, making its voyages ideal for long-term monitoring work in this region. We present data from its 2017/2018 voyage. In additions, a transects by the T/V Umitaka-maru was also carried out along 110E longitude in January 2018. Thus, this report provides the latest zooplankton data, forming part of the long-term monitoring of zooplankton carried out by JARE in this region for the last 40 years. These transect data can be used as time series and/or seasonal sets.