DNA barcoding is a valuable tool for biodiversity studies in the Southern Ocean. It can be combined with other types of systematics data (morphology, other sequence markers) to reassess the taxonomy of complex groups and reliably delineate species. It can serve as a precise identification tool for fisheries, ecology or large scale biodiversity surveys. The rise of Next Generation Sequencing (NGS) techniques in the last 15 years has provided exciting new developments in classical barcoding identification projects like fisheries identification control, benthic biodiversity survey and voucher-linked reference datasets creation, but also new possibilities like extension of barcoding to the whole mitogenomes and to communities through metabarcoding biodiversity surveys. We provide here some examples.

We present here the workflow of a large scale barcoding project of the benthic fauna of the French Exclusive Economic Zone of the Kerguelen archipelago. This project is part of a larger project that comparing faunistic assemblages through space and time, and aims to compute habitat models to highlight the structuration of the benthic communities and ecotypes spatial distribution. It will provide assessments and advice for the managers of the Marine Reserve. The barcoding project uses two complementary next-generation sequencing techniques and a multimarker approach to cover the whole taxonomic diversity of benthic macrofauna.

We here summarise the sampling effort and some preliminary findings from the 2019 Scotia Sea krill monitoring survey with the F/V Cabo de Hornos. The vessel was chartered by the Association of Responsible Harvesting Companies (ARK) and manned with personnel from the Institute of Marine Research to carry out a significant part of the 2019 Scotia Sea large scale krill monitoring. All sections of the large scale survey area were visited, and about 80 % of the coverage planned for the vessel was completed, the remaining had to be skipped due to time constraints. Altogether 3928 nautical miles were travelled on transects, and in addition to the acoustic data collection which is presented in a separate manuscript, 68 trawl stations for biological sampling with associated CTD casts were carried out. Marine mammals and birds were monitored continuously during daylight hours, as long as weather permitted. In addition, deployment of four acoustic moorings and 9 replicate measurements on board of krill acoustic sound speed and density contrasts were carried out. Euphausia superba dominated in the trawl samples on the shelf north of the south Shetland islands, in the Bransfield Strait, the shelf north of the South Orkneys and south of South Georgia. Salps, mainly Salpa thompsoni dominated north of the South Shetland shelf, and in the vast oceanic waters between the north and south Scotia ridge. Also amphipods, in particular Themisto gaudichaudii and other krill species dominated in some stations. E. superba length distribution were dominated by two modes, one of very large animals averaging around 55 mm dominating in the South Shetland area, and a second mode between 40 and 50 mm dominant further east, in particular around South Georgia. Small animals were only rarely sampled and almost uniquely on the shelf to the east of the Antarctic Peninsula. Fin whales were the dominating whale species in abundance, followed by humpback whales.

CCAMLR has defined Vulnerable Marine Ecosystems (VME) detection thresholds based on the benthos bycatch monitoring. When these thresholds are reached during a single longline fishing operation, the data are reported to the Secretariat to inform the CCAMLR about the potential presence of VME to be protected. Management decisions are triggered out according to various levels. Important catches of sea pens (Pennatulacea, NTW, VME bioindicator) in the 58.4.4b sector have been reported during the CCAMLR SAM Working Group 2018. However, despite the important level of the catches, no VME detection threshold triggering out the establishment of an immediate fishing exclusion zone have been reached. Here, we present the preliminary results and some discussion elements of a study centered on the case of the sea pens, and based on the data collected in the 58.4.4b sector. The results may indicate that (1) detection thresholds may be defined considering the taxa of the VME bioindicators, (2) the detection probability is both linked to the weight/size ratio of the organisms and to the ecology of the taxa.

As a contribution to the joint effort on the large-scale synoptic krill survey of Area 48, the Chinese krill fishing vessel Fu Rong Hai conducted the survey in the Subarea 48.1 from 2 February to 10 February 2019. A total distance of about 875 n. mile transect acoustic data was collected using a hull-mounted Simard EK60 echosounder (38, 70 and 120 kHz), and 10 planned stations were sampled for krill biology using a commercial midwater otter trawl.  Acoustic data processing were carried out generally following the procedures applied in the CCAMLR 2000 survey analyses, and estimates of krill density were based on the 120 kHz data attributed to krill using the swarm-based method as well as the two-frequency (S_v120-38kHz) identification methods. Results show that mean krill areal biomass density is relatively higher than the estimates of the CCAMLR2000 survey in the same area. Main objective of the present work is to introduce the implementation and preliminary results from the synoptic survey conducted by the Chinese vessel, and further cooperated analysis on the survey data might be done in the upcoming Subgroup on Acoustic Survey and Analysis Methods (SG-ASAM) meeting.

A multidisciplinary ecosystem survey in the eastern Indian sector of the Antarctic (CCAMLR Division 58.4.1) with a focus on Antarctic krill was carried out by Kaiyo-maru during the 2018/19 season for 53 days. The survey consisted of 2 survey periods: Leg 1 (from 15 December 2018 to January 2019; 24 days) and Leg 2 (from 26 January to 23 February 2019; 29 days). Leg 1 was commenced at ice edge on 80°E and ended at ice edge on 120°19.0’E. Leg 2 was commenced at 63°00.0’S on 150°00.0’E and ended at ice edge on 125°50.0’E. Two small scale oceanographic surveys (off the Mertz Glacier Tongue and the Totten Glacier) were also conducted during Leg 2. RMT tows were carried out at 72 stations (40 predetermined and 29 targeted stations with combination of both at 3 stations). SUIT tows were carried out at 28 stations. Quad NORPAC tows were carried out at 44 predetermined stations. Narrowband echosounder (38, 70, 120 and 200 kHz) data to estimate biomass of Antarctic krill were recorded along predetermined tracklines for 2,519 n.miles. Broadband echosounder data were recorded at 24 targeted RMT stations to estimate length distribution and swimming angles of Antarctic krill acoustically. The mass density and sound-speed contrasts against surrounding seawater of zooplanktons were measured 14 and 12 times, respectively. SADCP and PDR data were continuously recorded along the tracklines. A total of 101 CTD and 150 XCTD casts were made for physical and chemical oceanographic studies. Six types of autonomous profiling floats and buoys were deployed at 18 locations. Surface oceanographic environment data were continuously recorded along the tracklines. Sea ice (18 samples) and iceberg (15 samples) were collected for physical and chemical oceanographic studies. A total of 26 CTD casts were made for biological oceanographic studies. A total of 339 schools with 552 individuals of marine mammals were sighted during 1,249 n.miles of sighting effort along the tracklines. A total of 8,616 individuals of seabirds were sighted during 1,257 n.miles of sighting effort along the tracklines. Biological video recordings were made 25 times using 6 types of video recording devices. A number of analyses using obtained samples and data are in preparation and the results will be presented to the expert groups of SC-CAMLR.

China, Italy and Republic of Korea submitted to the next coming CEP XXII - ATCM XLII a proposal for the designation of a new Antarctic Specially Protected Area (ASPA) at Inexpressible Island and Seaview Bay, Ross Sea. The co-proponents have prepared the draft ASPA Management Plan annexed to this paper, in accordance with the requirements of Annex V to the Protocol on Environmental Protection to the Antarctic Treaty and the Revised Guide to the Preparation of Management Plans for Antarctic Specially Protected Areas (Resolution 2, 2011). The proposal is submitted to CCAMLR for its consideration, in accordance with ATCM Decision 9 (2005)

We provide a summary of environmental change in the Southern Ocean over the period of satellite observaton (1981 to present). The environmental data we consider are: (1) chlorophyll-a concentration from merged observation of SeaWiFS and MODIS-Aqua (1987–2019); (2) sea-surface temperature (SST) from the AVHRR series of NOAA satellites (1981–2019); (3) spatial gradient of SST (as an indicator of ocean fronts) from the same AVHRR observations; (4) sea ice concentration from microwave satellite sensors (SMMR, SSM/I); (5), net primary productivity (NPP) using the vertically-generalised productivity model (VGPM); (6) estimates of mixed layer depth from the data-assimilating US Navy hindcast model HyCOM (GLBu0.08); and (7) incident light intensity at the sea-surface. The data show heterogenous patterns of environmental change across the Southern Ocean over the last 4 decades. Key results are: (1) warming of the ocean surface north of the southern limit of the ACC and slight cooling to the south; (2) evidence of movement north of the Subantarctic Front; (3) increasing chl-a and NPP in the Subantarctic Front and around the southern limit of the ACC except in the Ross Sea region; (4) decreasing chl-a and NPP in the Ross Sea sector and on the Antarctic continental shelf; (5) gradual loss of sea-ice in the Amundsen Sea and increasing sea-ice in the Weddell, Bellingshausen and Ross Seas; (6) deepening of the mixed-layer near the Polar Front, contrasting with shallowing in the Ross Sea region, and both increases and decreases in different parts of the Weddell Sea; (7) increasing trends in incident light intensity in Subantarctic waters and generally decreasing trends near the Antarctic continent.

Understanding the variation in krill diet during winter is crucial to elucidate the overwintering of krill in the Southern Ocean. The information on trophic variation of krill under ice-free waters during the winter can also provide the insight for understanding the response of krill to global warming. Stable isotope analyses (¹⁵N/¹⁴N and ¹³C/¹²C) were utilized to explore the variation in diet of adult krill with size and month during the winter season (June to September 2016) at the South Georgia. Stable isotope signatures indicated that there were no significant differences in δ¹³C and δ¹⁵N values between sexes of krill. Nitrogen isotope signatures suggested increasing carnivory with size of adults throughout winter. Carbon isotope signatures revealed reduced food sources for the larger adults during early winter, but all adults could feed on similar food items during middle to late winter. The trophic niche of adults was similar during the winter season at the South Georgia. Our results provide insight for the diet of adult krill in the food-limited season and should be useful in understanding the energy transfer in the marine food web in the South Georgia ecosystem. Moreover, the information derived from this study can also be used to support krill fishery management and understand the interaction between krill population, top predators and fishery.

New Zealand carried out a 40-day voyage to the Ross Sea from 8 January to 16 February 2019 using the research vessel Tangaroa. The purpose of this multi-disciplinary research voyage was to increase knowledge about key environmental and biological processes in the Ross Sea region of Antarctica and the Southern Ocean, and thereby improve understanding of ecosystem function and likely responses to future change. The focus was on providing information relevant to the recently established Ross Sea region Marine Protected Area to allow scientific evaluation of its ecological status, spatial adequacy, and effectiveness. The eight voyage objectives spanned topics ranging from oceanography to bacteria to whales.