In this paper, we report recent changes in the spatial extent of the Pine Island Glacier. The 22% reduction in areal extent means that the newly exposed marine area has been classified as a Stage 1 Special Area for Scientific Study (SASS) in accordance with Conservation Measure 24-04.

This paper provides additional information to that included in COMM CIRC 21/76, allowing WG-EMM opportunity to comment.

As the most abundant penguin species, the diet of Adélie penguin, Pygoscelis adeliae, would be one of the most important indicators for the ecosystem conditions where they inhabit. The diet of seven Adélie penguin populations in the Ross Sea was studied using both metabarcoding and quantitative PCR (qPCR) analyses. 18Sv9 and miniFish primers provided the overall diet compositions and accurate fish species names, respectively. Based on the metabarcoding analysis, main prey items for Adélie penguin were notothenioid fish, Euphausia superba, and Euphausia crystallorophias varies from small fishes. Among the notothenioid fish, three species, including Pleuragramma antarctica, Pagothenia borchgrevinki, and Trematomus spp. were most abundant. qPCR analysis showed a significant geographical difference in the ratio between krill and notothenioids. Populations inhabiting inbound parts of Ross Sea (Edmonson Point and Inexpressible island) showed higher proportions of fish taxa without E. superba, while the other five populations exhibited a higher krill ratio to fish taxa with two krill. The ratio of krill to fish taxa was highly variable for three-year of study and showed annual synchronous patterns in observed populations, suggesting the long-term study for the penguin’s diet should be conducted to understand the relationship between the populations of Adélie penguin and their marine ecosystem in the Ross Sea.

To identify the dietary composition and characteristics of both Adélie (Pygoscelis adeliae) and emperor penguin (Aptenodytes forsteri) at four breeding sites, we performed stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope analysis of down of penguin chicks. Adélie penguin chicks at Cape Hallett mostly fed on Antarctic krill (Eupausia superba; 65.5±3.5%) reflecting the prevalence of that species near Cape Hallett, and no significant differences were noted between 2017 and 2018. However Adélie penguin chicks at Inexpressible Island located near Terra Nova Bay fed on both Antarctic silverfish (Pleuragramma antarctica; 42.5%) and ice krill (Euphausia crystallorophias; 47%) reflecting the high biomass observed in Terra Nova Bay. On the other hand, no significant difference was noted between at both breeding sites of the emperor penguin. Emperor penguin chicks predominantly fed on Antarctic silverfish (74.5±2.1%) at the breeding sites (Cape Washington and Coulman Island), suggesting that diet preference represents the main factor for emperor penguin foraging. In contrast, the diet of Adélie penguin reflected presumed regional differences in prey prevalence as inferred from available survey data.

Krill play a crucial role in the transfer of energy in the marine food web, connecting primary producers and the upper trophic levels in the Terra Nova Bay polynya (TNBP), which is part of the Ross Sea marine protected area. Despite the substantial ecological importance of krill, there are few studies on their distribution and abundance in the TNBP. An acoustic survey was conducted on 7–14 January 2019 in the TNBP, Ross Sea, using a Simrad EK60 echosounder (38 and 120 kHz) aboard the icebreaker RV Araon. The most commonly used range of the difference of the mean volume backscattering strength (MVBS) (2–16 dB) was applied to distinguish krill. The acoustic data (120 kHz) were extracted to examine the krill distribution characteristics. The study area was divided into low-value areas and high-value areas based on the third quartile of the nautical area scattering coefficient. The results showed that the krill aggregations were distributed in three layers at depths of 0–30 m, 70–110 m, and 270–300 m. The interpolated environmental parameters associated with the backscattering strength were compared. High-value areas of krill coincided with relatively low temperature, low salinity, and high chlorophyll, although very weak correlations were found. The primary goal of this study was to understand the vertical and horizontal distributions of krill acoustic biomass and to relate the observed patterns to the dominant environmental conditions.

Southern Ocean marine ecosystems are highly vulnerable to climate-driven change, the impacts of which must be factored into conservation and management. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is aware of the urgent need to develop climate-responsive options within its ecosystem approach to management. However, limited capacity as well as political differences have meant that little progress has been made. Strengthening scientific information flow to inform CCAMLR’s decision-making on climate change may help to remove some of these barriers. On this basis, this study encourages the utilisation of outputs from the United Nations’ Intergovernmental Panel on Climate Change (IPCC). The IPCC’s 2019 Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) constitutes the most rigorous and up-todate assessment of how oceans and the cryosphere are changing, how they are projected to change, and the consequences of those changes, together with a range of response options. To assist CCAMLR to focus on what is most useful from this extensive global report, SROCC findings that have specific relevance to the management of Southern Ocean ecosystems are extracted and summarised here. These findings are translated into recommendations to CCAMLR, emphasising the need to reduce and manage the risks that climate change presents to harvested species and the wider ecosystem of which they are part. Improved linkages between IPCC, CCAMLR and other relevant bodies may help overcome existing impediments to progress, enabling climate change to become fully integrated into CCAMLR’s policy and decision-making.

Recommendations.

CCAMLR is encouraged to continue working towards including climate change considerations in developing its management procedures, and to accelerate the pace of this work to ensure that management is responsive to the effects of change, thereby reducing the risks of additional negative ecosystem impacts. To enhance the scientific foundation for decision-making with specific relevance to climate change, it is recommended that CCAMLR:

1. Assesses the risks climate change presents to its objectives using available information sources:

• Improves mechanisms to coordinate and undertake targeted activities in support of identifying and integrating relevant scientific research outputs on climate change into the work of the Scientific Committee and its Working Groups. • Invites contributions from external experts to ensure access to additional relevant expertise as appropriate. • Further develops mechanisms to ensure that CCAMLR is well informed about climate change research, particularly as the UN IPCC process continues to develop relevant outputs, including AR6 and all subsequent reports. This could involve the establishment of a standing Working Group on Climate Change that reports directly to the Scientific Committee. • Encourages input by its Members to the IPCC process as authors and reviewers, as well as through contributions to the published literature.

2. Identifies the most important risks and aims to understand, reduce and manage these risks:

• Encourages research focused on the continued conservation of Southern Ocean ecosystems in a changing climate by facilitating relevant data collection and responding appropriately to relevant findings. • Actively engages with SCAR, SOOS, ICED and other relevant bodies to develop priorities for scientific research. • Actively engages with organisations or others that manage vessels or assets that might increase opportunities for collection of relevant information, e.g., International Association of Antarctica Tour Operators (IAATO) and Association of Responsible Krill harvesting companies (ARK). • Actively engages with diverse stakeholders to facilitate knowledge-exchange and consider stakeholder values in decision-making processes related to climate change and ecosystem based management.

3. Ensures timely responses to information about these risks, including what action will be taken:

• Develops a work programme with the specific aim of ensuring that the management of all CCAMLR managed fisheries incorporates planning and adaptation pathways that include short-, medium- and longer-term actions to minimise climate change impacts on harvested species and the ecosystem.

In the second decade of February 2021, the Ukrainian longliner CALIPSO performed the research survey with the bottom longline in the northwestern part of the Weddell Sea (statistical subarea 48.1). The work was carried out in accordance with the research plan SC-CAMLR-39/BG/08. Ukraine went on the operations with deep-sea video camera to get the video data which was started on February 2020.

During the survey at two longline stations in the Research block 48.1_2, a set of equipment for underwater video recording was attached to the fishing gear - underwater video recording system (referred to as UVS). In this way one 4.5 hours video footages were successfully recorded.

Understanding the spatial and temporal distributions of fishes and other Antarctic ecosystem components is critical criteria of the conservation and ecosystem management. Here, we report on continuing a non-extractive method for the study of benthic wildlife, based on UVS.

Together with the video recording, oceanological parameters (depth, temperature and salinity) were also recorded with the DST CTD.

Spatial scale is the common ground of all of the three components (Biomass estimation, stock assessment and risk assessment) for the new krill management strategy. The pros and cons of the potential choices of biomass estimate at various spatial scales were discussed to facilitate the deliberation on Krill Stock Assessment at the WG-SAM-2021 meeting. Considerations were also given on the spatial scale that is appropriate both for acoustic biomass estimation and stock assessment, and on the pragmatic approach to implement the new krill management strategy in an efficient manner. Discussions were focused on the work in Subarea 48.1, but some of these considerations may also be applicable in other Subareas.

CCAMLR has now endorsed a new strategy for the management of Antarctic krill Euphausia superba. This combines outputs from a (i) Generalised Yield Model, (ii) updated krill biomass estimate, and (iii) a risk assessment, to identify catch limits and their spatial distribution for the krill fishery so that harvesting remains precautionary. The risk assessment can be used to identify how to spread the catch in order to minimise risks to krill dependent predators and to juvenile krill. The framework combines three components: localised risk to predators, localised risk to krill and desirability to the fishery. Localised risk to predators relates to the potential for interference by the fishery on predator foraging performance. Predation pressure (consumption of krill as a proportion of biomass of krill) is used as an index of predator risk. Localised risk to krill includes areas dominated by juvenile krill. The desirability to the fishery is a measure of the relative importance of each area to the fishery.

In this paper we report on the ongoing development of the data layers necessary to implement the risk assessment in Subareas 48.2 and 48.3.