Description: Human-induced habitat destruction, overexploitation, introduction of alien species and climate change are causing species to go extinct at unprecedented rates, from local to global scales. There are growing concerns that these kinds of disturbances alter important functions of ecosystems. Our current understanding is that key parameters of a community (e.g. its functional diversity, species composition, and presence/absence of vulnerable species) reflect an ecological network’s ability to resist or rebound from change in response to pressures and disturbances, such as species loss. If the food web structure is relatively simple, we can analyse the roles of different species interactions in determining how environmental impacts translate into species loss. However, when ecosystems harbour species-rich communities, as is the case in most natural systems, then the complex network of ecological interactions makes it a far more challenging task to perceive how species’ functional roles influence the consequences of species loss. One approach to deal with such complexity is to focus on the functional traits of species in order to identify their respective roles: for instance, large species seem to be more susceptible to extinction than smaller species. Here, we introduce and analyse the marine food web from the high Antarctic Weddell Sea Shelf to illustrate the role of species traits in relation to network robustness of this complex food web. Our approach was threefold: firstly, we applied a new classification system to all species, grouping them by traits other than body size; secondly, we tested the relationship between body size and food web parameters within and across these groups and finally, we calculated food web robustness. We addressed questions regarding (i) patterns of species functional/trophic roles, (ii) relationships between species functional roles and body size and (iii) the role of species body size in terms of network robustness. Our results show that when analyzing relationships between trophic structure, body size and network structure, the diversity of predatory species types needs to be considered in future studies.

Description: Here we provide two ArcGIS map packages with georeferenced files on the spatial distribution of sponges and echinoderms in the wider Weddell Sea (Antarctica), which were created in the context of the development of a marine protected area (MPA) in the Weddell Sea. Sponges: The map of interpolated occurrence of sponges is based on quantitative abundance data (Gerdes 2014 a - o) and on semi-quantitative data obtained by W. Arntz (retired; formerly AWI) (see Teschke & Brey 2019a for presence / absence records of the latter dataset). The abundance data were classified to be merged with the semi-quantitative data and an inverse distance weighted method was performed on the united dataset. Areas with very common occurrence of sponges occurred on the shelf near Brunt Ice Shelf along Riiser - Larsen Ice Shelf to Ekstrøm Ice Shelf. Echinoderms: A cluster analysis with species x station datasets of asteroids (Teschke & Brey 2019b), ophiuroids (Teschke & Brey 2019c) and holothurians (Gutt et al. 2014) from the Antarctic Weddell Sea indicated a particular cold-water echinoderm fauna on the Filchner shelf. We approximated this potential habitat by bottom temperature ≤ -1°, based on seawater temperature data from the Finite Element Sea Ice - Ocean Model provided by R. Timmermann (AWI). More information on the spatial analysis is given in working paper WG-EMM-16/03 submitted to the CCAMLR Working Group on Ecosystem Monitoring and Management (available at https://www.ccamlr.org/en/wg-emm-16).

Description: Here we provide four ArcGIS map packages with georeferenced files on the spatial distribution of demersal and pelagic fishes in the wider Weddell Sea (Antarctica), which were created in the context of the development of a marine protected area (MPA) in the Weddell Sea. Antarctic toothfish: The map of Dissostichus mawsoni occurrence probability is based on catch per unit effort (CPUE) data from the database of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) (data request: 03-08-2016) and on bathymetric data from the International Bathymetric Chart of the Southern Ocean (IBCSO). We fitted a four-parameter Weibull model to the simulated CPUE data per depth interval by means of the R package \textquotesinglefitdistrplus\textquotesingle. The highest D. mawsoni occurrence probability was shown at depths between 1500 and 2000 m and only approximately 20 % of the Antarctic toothfish population occurred deeper than 2000 m. Antarctic silverfish: The map of interpolated abundances of Pleuragramma antarctica was based on pelagic trawl survey data, which were collected during "Polarstern" cruises ANT-I/2, ANT-III/3 and in the context of the Lazarev Sea Krill Survey (LAKRIS) ("Polarstern" cruises ANT-XXI/4, ANT-XXIII/6, ANT-XXIV/2). The first mentioned data were provided by V. Siegel (retired; formerly Th\"unen Institute), the LAKRIS data by H. Flores (AWI). Those data were complemented by benthic trawl survey data, which were collected during seven "Polarstern" cruises between 1996 and 2011 (ANT-XIII/3, ANT-XV/3, ANT-XVII/3, ANT-XIX/5, ANT-XXI/2, ANT-XXIII/8, ANT-XXVII/3) and were provided by R. Knust (AWI) as well as by data on counts of fish species from trawl and dredge samples by Drescher et. (2012), Ekau et al. (2012a, b), Hureau et al. (2012), Kock et al. (2012) and W\"ohrmann et al. (2012). An inverse distance weighted interpolation was performed for a 10 nautical mile radius around each record. Areas with highest numbers of P. antarctica (〉 36 individuals/1000 m²) occurred offshore Riiser -Larsen Ice Shelf and on the southern Weddell Sea continental shelf offshore Filchner Ice Shelf. Demersal fish: The map of predicted habitat suitability for demersal fish is based on data, which were collected during seven "Polarstern" cruises between 1996 and 2011 (ANT-XIII/3, ANT-XV/3, ANT-XVII/3, ANT-XIX/5, ANT-XXI/2, ANT-XXIII/8, ANT-XXVII/3) and were provided by R. Knust (AWI). The habitat suitability model was developed by the use of the modelling package "biomod2". Most suitable habitat conditions for demersal fish in the wider Weddell Sea occurred on the continental shelf between approx. 5° and 30°W, on the shelf west and east of the tip of the Antarctic Peninsula as well as around the South Shetland and South Orkney Islands. Nesting sites of demersal fish: The map on observation of nesting sites of demersal fish is based on data, which were collected during "Polarstern" cruises ANT-XXVII/3, ANT-XXIX/9 and ANT-XXXI/2 and were obtained by T. Lund\"alv (retired; formerly University of Gothenburg), D. Gerdes (retired; formerly AWI) and E. Riginella (University of Padova), respectively. Those data were complemented by a literature research. Most nesting sites were observed west of 25°W, north of the tip of the Antarctic Peninsula and along the west coast of the Antarctic Peninsula. More information is given in the working paper WG-EMM-16/03 submitted to the CCAMLR Working Group on Ecosystem Monitoring and Management CCAMLR (available at https://www.ccamlr.org/en/wg-emm-16). Revised versions of the spatial analysis are described in working paper WG-SAM-17/30 and WS-SM-18/13 submitted to the CCAMLR Working Group on Statistics, Assessments and Modelling and the CCAMLR Workshop on Spatial Management, respectively (available at https://www.ccamlr.org/en/wg-sam-17; https://www.ccamlr.org/en/ws-sm-1

Description: Here, we provided four ArcGIS map packages with georeferenced files on the spatial distribution of Antarctic krill, Euphausia superba, (adults and larvae) and ice krill, Euphausia crystallorophias, in the wider Weddell Sea. The files were created in the context of the development of a marine protected area in the Weddell Sea. Antarctic krill (adults): The map of predicted habitat suitability for adult Antarctic krill was based on krill data from the database KRILLBASE (Atkinson et al., 2017; data request: 26-09-13). Those data were complemented by krill data, which were collected (a) during the Norwegian Antarctic research expedition 1976/77 (M/V "Polarsirkel"), (b) during two Soviet research cruises (RV "Gizhiga", 1977; RV "Volny Vetter", 1983), (c) in the context of the Lazarev Sea Krill Survey ("Polarstern" cruises ANT-XXI/4, ANT-XXIII/2, ANT-XXIII/6, ANT-XXIV/2) as well as (d) during "Polarstern" cruise ANT-XXIX/3. The habitat suitability model was developed by the use of the modelling package "biomod2". As predictor variables, we used (i) dissolved oxygen from the World Ocean Atlas 2013, (ii) ice coverage from AMSR-E sea ice maps, (iii) seawater temperature data from the Finite Element Sea Ice - Ocean Model (FESOM) provided by R. Timmermann (AWI), (iv) bathymetric data from the International Bathymetric Chart of the Southern Ocean (IBCSO) and (v) SeaWiFS chlorophyll-a concentration data. Most suitable habitat conditions for the Antarctic krill seem to occur near the tip of the Antarctic Peninsula, on the continental slope between 15°W and 15°E and on the Maud Rise plateau. Antarctic krill (larvae): The map of interpolated abundances of krill larvae is based on abundance data, which were collected (a) during the Norwegian Antarctic research expeditions 1976/77, 1977/78 and 1979/80 (M/V "Polarsirkel"), (b) in the context of the First International BIOMASS Experiment survey (FIBEX) (Walther Herwig cruise 1981) and the Lazarev Sea Krill Survey (LAKRIS) ("Polarstern" cruises ANT-XXI/4, ANT-XXIII/6) as well as (c) during "Polarstern" cruise ANT-VII/4 and the combined "Polarstern" (ANT-VIII/2) and R.V. "Akademik Fedorova" cruise. An inverse distance weighted (IDW) interpolation was performed for a 30 km radius around each krill larvae record. Areas with highest numbers of E. superba larvae (〉 1000 individuals/m²) occurred west of the Prime Meridian from approximately 65°S to the ice shelf. Ice krill (adults): The map of the potential habitat of E. crystallorophias was approximated by water depth from 0 m to 550 m, using bathymetric data from IBCSO, and mean sea surface temperature ≤ 0°C based on temperature data from FESOM provided by R. Timmermann (AWI). The map of interpolated density of individuals of E. crystallorophias is based on abundance data, which were collected (a) during the Norwegian Antarctic research expedition 1979/80 (M/V "Polarsirkel"), (b) during the German Antarctic research cruise 1975/76 with "Walther Herwig", (c) in the context of the Lazarev Sea Krill Survey ("Polarstern" cruises ANT-XXI/4, ANT-XXIII/2, ANT-XXIII/6, ANT-XXIV/2) as well as (d) during "Polarstern" cruise ANT-V/1-3, ANT-VII/4 and ANT-XXIX/3. An IDW interpolation was performed for a 30 km radius around each record of ice krill. Areas with highest densities of E. crystallorophias individuals occurred on the south-eastern Weddell Sea shelf and near the tip of the Antarctic Peninsula. Volker Siegel (retired; formerly Th\"unen Institute) provided the data for the Antarctic krill and ice krill. More information on the spatial analysis is given in working paper WG-EMM-16/03 submitted to the CCAMLR Working Group on Ecosystem Monitoring and Management (available at https://www.ccamlr.org/en/wg-emm-16)