ALBERT

Description: Over the last decade, several hundred seals have been equipped with conductivity-temperature-depth sensors in the Southern Ocean for both biological and physical oceanographic studies. A calibrated collection of seal-derived hydrographic data is now available, consisting of more than 165,000 profiles. The value of these hydrographic data within the existing Southern Ocean observing system is demonstrated herein by conducting two state estimation experiments, differing only in the use or not of seal data to constrain the system. Including seal-derived data substantially modifies the estimated surface mixedlayer properties and circulation patterns within and south of the Antarctic Circumpolar Current. Agreement with independent satellite observations of sea ice concentration is improved, especially along the East Antarctic shelf. Instrumented animals efficiently reduce a critical observational gap, and their contribution to monitoring polar climate variability will continue to grow as data accuracy and spatial coverage increase.

Description: Polar oceans are poorly monitored despite the important role they play in regulating Earth’s climate system. Marine mammals equipped with biologging devices are now being used to fill the data gaps in these logistically difficult to sample regions. Since 2002, instrumented animals have been generating exceptionally large data sets of oceanographic CTD casts (〉500,000 profiles), which are now freely available to the scientific community through the MEOP data portal (http://meop.net). MEOP (Marine Mammals Exploring the Oceans Pole to Pole) is a consortium of international researchers dedicated to sharing animal-derived data and knowledge about the polar oceans. Collectively, MEOP demonstrates the power and cost-effectiveness of using marine mammals as data-collection platforms that can dramatically improve the ocean observing system for biological and physical oceanographers. Here, we review the MEOP program and database to bring it to the attention of the international community.

Description: Southern Ocean ecosystems are under pressure from resource exploitation and climate change. Mitigation requires the identification and protection of Areas of Ecological Significance (AESs), which have so far not been determined at the ocean-basin scale. Here, using assemblage-level tracking of marine predators, we identify AESs for this globally important region and assess current threats and protection levels. Integration of more than 4,000 tracks from 17 bird and mammal species reveals AESs around sub- Antarctic islands in the Atlantic and Indian Oceans and over the Antarctic continental shelf. Fishing pressure is disproportionately concentrated inside AESs, and climate change over the next century is predicted to impose pressure on these areas, particularly around the Antarctic continent. At present, 7.1% of the ocean south of 40°S is under formal protection, including 29% of the total AESs. The establishment and regular revision of networks of protection that encompass AESs are needed to provide long-term mitigation of growing pressures on Southern Ocean ecosystems.

Description: Seals help gather information on some of the harshest environments on the planet, through the use of miniaturized ocean sensors glued on their fur. The resulting data – gathered from remote, icy seas over the last decade – are now freely available to scientists around the world from the data portal http://www.meop.net. The Polar oceans are changing rapidly as a result of global warming. Ice caps in Antarctica and Greenland are melting, releasing large quantities of freshwater into surface waters. The winter sea ice cover is receding in the Arctic and in large areas of the Southern Ocean, which promotes further warming. Southern winds are intensifying for reasons that are not fully understood. To understand the changing marine environment, it is necessary to have a comprehensive network of oceanographic measurements. Yet, until recently, the harsh climate and remoteness of these areas make them extremely difficult to observe. Diving marine animals equipped with sensors are now increasingly filling in the gaps. When diving animals help us to observe the oceans Since 2004, hundreds of diving marine animals, mainly Antarctic and Arctic seals, were fitted with a new generation of Argos tags developed by the Sea Mammal Research Unit of the University of St. Andrews in Scotland (Fig. 1). These tags can be used to investigate simultaneously the at-sea ecology (displacement, behaviour, dives, foraging success...) of these animals while collecting valuable oceanographic data (Boehme et al. 2009). Some of these species are travelling thousands of kilometres continuously diving to great depths (590 ± 200 m, with maxima around 2000m). The overall objective of most marine animal studies is to assess how their foraging behavior responds to oceanographic changes and how it affects their ability to aquire the resources they need to survive. But in the last decade, these animals have become an essential source of temperature and salinity profiles, especially for the polar oceans. For example, elephant seals and Weddell seals have contributed 98 % of the existing temperature and salinity profiles within the Southern Ocean pack ice. The sensors are non-invasive (attached to the animal’s fur, they naturally fall off when the animal moults) and the only devices of their kind that can be attached to animals. MEOP: an international data portal for ocean data collected by marine animals The international consortium MEOP (Marine mammals Exploring the Ocean Pole-to-pole), originally formed during the International Polar Year in 2008-2009, aims to coordinate at the global scale animal tag deployments, oceanographic data processing and data distribution. The MEOP consortium includes participants from 12 countries (Australia, Brazil, Canada, China, United Kingdom, United States, France, Germany, Greenland, Norway, South Africa and Sweden). The MEOP consortium is associated with GOOS (Global Ocean Observing System), POGO (Partnership for Observation of the Global Oceans), and SOOS (Southern Ocean Observing System). At the European level, the European Animal-Borne Instrument (ABI) EuroGOOS Task Team is about to be launched to facilitate and promote the use of animal-borne instruments. Over 300,000 oceanographic profiles (i.e. representing 1/3 of the total number of Argo profiles) collected by marine biologists have already been made freely available to the international community through the MEOP data portal (Fig. 2). This so-called MEOP-CTD database is a significant contribution to the observation of the world ocean that can be used to conduct regional Polar studies. The MEOP-CTD database of animal-derived temperature and salinity profiles An increasing number of studies now show the importance of these remote and inaccessible parts of the ocean, which are so difficult to observe. For example, more than 90% of extra heat in the Earth system is now stored in the oceans and the Southern Ocean in particular is a key site for understanding the uptake of heat and carbon. MEOP provides several thousand oceanographic profiles per year helping us to close gaps in our understanding of the climate system. Instrumented animals complement efficiently other existing observing systems, such as Argo buoys, providing data in sea-ice covered areas and on high-latitude continental shelves. Recent published work (Roquet et al. 2013; Roquet et al. 2014) has shown how important such observations are in predicting ice cover and mixed layer depth in large parts of the oceans where the observations were made. The inclusion of these data should improve significantly the quality of the projections provided by ocean-climate models. All these data are now available into a format file (Argo standard format) easily usable by oceanographers and accessible via the MEOP portal where it can be freely and easily downloaded by users (national data centers, researchers...) with a guaranteed quality level. This database is updated on an annual basis, and it has already been integrated into major oceanographic data centres including NODC, BODC and Coriolis. Figures Figure 1: Weddell seal carrying a SRDL-CTD instrument that collects temperature and salinity profiles while the animal is at sea (Credits: D. Costa). Figure 2: Distribution of hydrographic data in the MEOPCTD database for the Southern Ocean sector (source: meop.net). References Boehme, L. et al., 2009. Technical Note: Animal-borne CTD-Satellite Relay Data Loggers for real-time oceanographic data collection. Ocean Science, 5:685-695. Roquet F. et al., 2013. Estimates of the Southern Ocean General Circulation Improved by Animal-Borne Instruments. Geoph. Res. Letts., 40:1-5. doi: 10.1002/2013GL058304 Roquet F. et al., 2014. A Southern Indian Ocean database of hydrographic profiles obtained with instrumented elephant seals. Nature Scientific Data, 1:140028, doi: 10.1038/sdata.2014.28

Description: The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for multiple species of Antarctic meso- and top-predators to identify Areas of Ecological Significance. These datasets and accompanying syntheses provide a greater understanding of fundamental ecosystem processes in the Southern Ocean, support modelling of predator distributions under future climate scenarios and create inputs that can be incorporated into decision making processes by management authorities. In this data paper, we present the compiled tracking data from research groups that have worked in the Antarctic since the 1990s. The data are publicly available through biodiversity.aq and the Ocean Biogeographic Information System. The archive includes tracking data from over 70 contributors across 12 national Antarctic programs, and includes data from 17 predator species, 4060 individual animals, and over 2.9 million observed locations.

Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Harcourt, R., Hindell, M. A., McMahon, C. R., Goetz, K. T., Charrassin, J.-B., Heerah, K., Holser, R., Jonsen, I. D., Shero, M. R., Hoenner, X., Foster, R., Lenting, B., Tarszisz, E., & Pinkerton, M. H. Regional variation in winter foraging strategies by Weddell Seals in Eastern Antarctica and the Ross Sea. Frontiers in Marine Science, 8, (2021): 720335, https://doi.org/10.3389/fmars.2021.720335.

Description: The relative importance of intrinsic and extrinsic determinants of animal foraging is often difficult to quantify. The most southerly breeding mammal, the Weddell seal, remains in the Antarctic pack-ice year-round. We compared Weddell seals tagged at three geographically and hydrographically distinct locations in East Antarctica (Prydz Bay, Terre Adélie, and the Ross Sea) to quantify the role of individual variability and habitat structure in winter foraging behaviour. Most Weddell seals remained in relatively small areas close to the coast throughout the winter, but some dispersed widely. Individual utilisation distributions (UDi, a measure of the total area used by an individual seal) ranged from 125 to 20,825 km2. This variability was not due to size or sex but may be due to other intrinsic states for example reproductive condition or personality. The type of foraging (benthic vs. pelagic) varied from 56.6 ± 14.9% benthic dives in Prydz Bay through 42.1 ± 9.4% Terre Adélie to only 25.1 ± 8.7% in the Ross Sea reflecting regional hydrographic structure. The probability of benthic diving was less likely the deeper the ocean. Ocean topography was also influential at the population level; seals from Terre Adélie, with its relatively narrow continental shelf, had a core (50%) UD of only 200 km2, considerably smaller than the Ross Sea (1650 km2) and Prydz Bay (1700 km2). Sea ice concentration had little influence on the time the seals spent in shallow coastal waters, but in deeper offshore water they used areas of higher ice concentration. Marine Protected Areas (MPAs) in the Ross Sea encompass all the observed Weddell seal habitat, and future MPAs that include the Antarctic continental shelf are likely to effectively protect key Weddell seal habitat.

Description: Field support was provided in the Ross Sea by Malcolm O’Toole, Rupert Woods, and Antarctica New Zealand and in Prydz Bay by Malcolm O’Toole, Andrew Doube, Iain Field, and the Australian Antarctic Division. The tagging study in Terre Adélie had logistical support from IPEV (Institut Paul Emile Victor) and the French Polar Institute. New Zealand funding was provided by the Ministry for Business, Innovation and Employment Endeavour Fund C01 × 1710: “RAMPing-up protection of the Ross Sea”. The 2014 field event was funded by NZARI (NZ Antarctic Research Institute) and Fisheries New Zealand (respectively), with Regina Eisert as CI, and tags and some field personnel funded by IMOS. The IMOS deployments in Prydz Bay were supported logistically by the Australian Antarctic Division through the Australian Antarctic Science Grant Scheme (AAS Projects 2794 & 4329). The tagging study in Terre Adélie was supported by the Program Terre-Océan-Surface Continentale-Atmosphère from Centre National d’Etudes Spatiales (TOSCA-CNES). The ARGOS seal tracking and dive data were sourced and are available from the Integrated Marine Observing System (IMOS), NIWA, and LOCEAN. IMOS is a national collaborative research infrastructure, supported by the Australian Government. It is operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as lead agent.

Description: Quantifying the population trends of higher order predators provides an especially informative and tractable indicator of ecosystem health. Therefore, regular censuses are fundamental for the management of animal populations but are logistically challenging for species living in the Southern Ocean. High-resolution satellite images of Earth, which are increasingly available for civilian applications, can discern individual large animals and permit, for the first time, the possibility of estimating populations on regional to continental scales. Pack ice seals are an important component of the Southern Ocean ecosystem, yet are notoriously difficult to census as they are sparsely distributed over large regions, are highly mobile, and hence their haul out sites onto the ice are unpredictable. Accordingly, historically population estimates have been derived through a combination of counts and models to accommodate the detection rate of animals, both of which are constrained when surveys are limited in spatial and temporal coverage. We will use counts derived from satellite imagery to estimate abundance of pack ice seals and to, ultimately, quantify population trends in this important group. In the Southern Ocean, estimates of seal abundance are needed to set precautionary catch limits for the burgeoning fisheries and in view of the management of Marine Protected Areas in that region. This study will define a pathway for satellite imagery and remote sensing techniques to be used for inaccessible species of wildlife in other management frameworks worldwide.