Targeting fin whale conservation in the North-Western Mediterranean Sea : insights on movements and behaviour from biologging and habitat modelling

Open Access via the Royal Society Agreement The fieldwork was supported by Giancarlo Lauriano/ISPRA, who provided transmitters for the 2021 season, and the Friedlaender Lab (UCSC), who provided tags for the 2022 and 2023 seasons, together with SPA-RAC and Tethys Research Institute who contributed with partial funding.Peer reviewe

Fine-scale foraging behaviour of female northern elephant seals during the entire post-breeding migration

第32回極域生物シンポジウムポスター発

Relationship between red blood cell lifespan and endogenous carbon monoxide in the common bottlenose dolphin and beluga

Certain deep-diving marine mammals (i.e., northern elephant seal (Mirounga angustirosis), Weddell seal (Leptonychotes weddellii)) have blood carbon monoxide (CO) levels that are comparable to those of chronic cigarette smokers. Most CO produced in humans is a by-product of heme degradation, which is released when red blood cells (RBC) are destroyed. Elevated CO can occur in humans when RBC lifespan decreases. The contribution of RBC turnover to CO concentrations in marine mammals is unknown. Here, we report the first RBC lifespans in two healthy, marine mammal species with different diving capacities and heme stores, the shallow diving bottlenose dolphin (Tursiops truncatus) and deep-diving beluga (Delphinapterus leucas) and relate the lifespans to the levels of CO in blood and breath. The belugas, with high blood heme stores, had the longest mean RBC lifespan compared to humans and bottlenose dolphins. Both cetacean species were found to have three times higher blood CO content compared to humans. The estimated CO production rate from heme degradation indicates some marine mammals may have additional mechanisms for CO production, or delay CO removal from the body, potentially from long duration breath-holds

Oceanic Controls on the Mass Balance of Wilkins Ice Shelf, Antarctica

Several Antarctic Peninsula (AP) ice shelves have lost significant fractions of their volume over the past decades, coincident with rapid regional climate change. Wilkins Ice Shelf (WIS), on the western side of the AP, is the most recent, experiencing a sequence of large calving events in 2008 and 2009. We analyze the mass balance for WIS for the period 1992-2008 and find that the averaged rate of ice-shelf thinning was similar to 0.8 m a(-1), driven by a mean basal melt rate of \u3c w(b)\u3e = 1.3 +/- 0.4 m a(-1). Interannual variability was large, associated with changes in both surface mass accumulation and \u3c w(b)\u3e. Basal melt rate declined significantly around 2000 from 1.8 +/- 0.4 m a(-1) for 1992-2000 to similar to 0.75 +/- 0.55 m a(-1) for 2001-2008; the latter value corresponding to approximately steady-state ice-shelf mass. Observations of ocean temperature T obtained during 2007-2009 by instrumented seals reveal a cold, deep halo of Winter Water (WW; T approximate to - 1.6 degrees C) surrounding WIS. The base of the WW in the halo is similar to 170 m, approximately the mean ice draft for WIS. We hypothesize that the transition in \u3c w(b)\u3e in 2000 was caused by a small perturbation (similar to 10-20 m) in the relative depths of the ice base and the bottom of the WW layer in the halo. We conclude that basal melting of thin ice shelves like WIS is very sensitive to upper-ocean and coastal processes that act on shorter time and space scales than those affecting basal melting of thicker West Antarctic ice shelves such as George VI and Pine Island Glacier

Circumpolar habitat use in the southern elephant seal : implications for foraging success and population trajectories

In the Southern Ocean, wide-ranging predators offer the opportunity to quantify how animals respond to differences in the environment because their behavior and population trends are an integrated signal of prevailing conditions within multiple marine habitats. Southern elephant seals in particular, can provide useful insights due to their circumpolar distribution, their long and distant migrations and their performance of extended bouts of deep diving. Furthermore, across their range, elephant seal populations have very different population trends. In this study, we present a data set from the International Polar Year project; Marine Mammals Exploring the Oceans Pole to Pole for southern elephant seals, in which a large number of instruments (N = 287) deployed on animals, encompassing a broad circum-Antarctic geographic extent, collected in situ ocean data and at-sea foraging metrics that explicitly link foraging behavior and habitat structure in time and space. Broadly speaking, the seals foraged in two habitats, the relatively shallow waters of the Antarctic continental shelf and the Kerguelen Plateau and deep open water regions. Animals of both sexes were more likely to exhibit area-restricted search (ARS) behavior rather than transit in shelf habitats. While Antarctic shelf waters can be regarded as prime habitat for both sexes, female seals tend to move northwards with the advance of sea ice in the late autumn or early winter. The water masses used by the seals also influenced their behavioral mode, with female ARS behavior being most likely in modified Circumpolar Deepwater or northerly Modified Shelf Water, both of which tend to be associated with the outer reaches of the Antarctic Continental Shelf. The combined effects of (1) the differing habitat quality, (2) differing responses to encroaching ice as the winter progresses among colonies, (3) differing distances between breeding and haul-out sites and high quality habitats, and (4) differing long-term regional trends in sea ice extent can explain the differing population trends observed among elephant seal colonies.Publisher PDFPeer reviewe

Scaling up ocean conservation through recognition of key biodiversity areas in the Southern Ocean from multispecies tracking data

Biodiversity is critical for maintaining ecosystem function but is threatened by increasing anthropogenic pressures. In the Southern Ocean, a highly biologically productive region containing many endemic species, proactive management is urgently needed to mitigate increasing pressures from fishing, climate change, and tourism. Site-based conservation is one important tool for managing the negative impacts of human activities on ecosystems. The Key Biodiversity Area (KBA) Standard is a standardized framework used to define sites vital for the persistence of global biodiversity based on criteria and quantitative thresholds. We used tracking data from 14 species of Antarctic and subantarctic seabirds and pinnipeds from the publicly available Retrospective Analysis of Antarctic Tracking Data (RAATD) data set to define KBAs for a diverse suite of marine predators. We used track2kba, an R package that supports identification of KBAs from telemetry data through identification of highly used habitat areas and estimates of local abundance within sites. We compared abundance estimates at each site with thresholds for KBA criteria A1, B1, and D1 (related to globally threatened species, individual geographically restricted species, and demographic aggregations, respectively). We identified 30 potential KBAs for 13 species distributed throughout the Southern Ocean that were vital for each individual species, population, and life-history stage for which they were determined. These areas were identified as highly used by these populations based on observational data and complement the ongoing habitat modeling and bioregionalization work that has been used to prioritize conservation areas in this region. Although further work is needed to identify potential KBAs based on additional current and future data sets, we highlight the benefits of utilizing KBAs as part of a holistic approach to marine conservation, given their significant value as a global conservation tool

The retrospective analysis of Antarctic tracking data project

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

The retrospective analysis of Antarctic tracking data project

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.Supplementary Figure S1: Filtered location data (black) and tag deployment locations (red) for each species. Maps are Lambert Azimuthal projections extending from 90° S to 20° S.Supplementary Table S1: Names and coordinates of the major study sites in the Southern Ocean and on the Antarctic Continent where tracking devices were deployed on the selected species (indicated by their 4-letter codes in the last column).Online Table 1: Description of fields (column names) in the metadata and data files.Supranational committees and organisations including the Scientific Committee on Antarctic Research Life Science Group and BirdLife International. National institutions and foundations, including but not limited to Argentina (Dirección Nacional del Antártico), Australia (Australian Antarctic program; Australian Research Council; Sea World Research and Rescue Foundation Inc., IMOS is a national collaborative research infrastructure, supported by the Australian Government and operated by a consortium of institutions as an unincorporated joint venture, with the University of Tasmania as Lead Agent), Belgium (Belgian Science Policy Office, EU Lifewatch ERIC), Brazil (Brazilian Antarctic Programme; Brazilian National Research Council (CNPq/MCTI) and CAPES), France (Agence Nationale de la Recherche; Centre National d’Etudes Spatiales; Centre National de la Recherche Scientifique; the French Foundation for Research on Biodiversity (FRB; www.fondationbiodiversite.fr) in the context of the CESAB project “RAATD”; Fondation Total; Institut Paul-Emile Victor; Programme Zone Atelier de Recherches sur l’Environnement Antarctique et Subantarctique; Terres Australes et Antarctiques Françaises), Germany (Deutsche Forschungsgemeinschaft, Hanse-Wissenschaftskolleg - Institute for Advanced Study), Italy (Italian National Antarctic Research Program; Ministry for Education University and Research), Japan (Japanese Antarctic Research Expedition; JSPS Kakenhi grant), Monaco (Fondation Prince Albert II de Monaco), New Zealand (Ministry for Primary Industries - BRAG; Pew Charitable Trusts), Norway (Norwegian Antarctic Research Expeditions; Norwegian Research Council), Portugal (Foundation for Science and Technology), South Africa (Department of Environmental Affairs; National Research Foundation; South African National Antarctic Programme), UK (Darwin Plus; Ecosystems Programme at the British Antarctic Survey; Natural Environment Research Council; WWF), and USA (U.S. AMLR Program of NOAA Fisheries; US Office of Polar Programs).http://www.nature.com/sdataam2021Mammal Research Institut

Dealing with a fast changing environment: the trophic ecology of the southern elephant seal (Mirounga leonina) and crabeater seal (Lobodon carcinophaga) in the western Antarctica Peninsula

The foraging behavior of top predators is linked to the distribution and abundance of prey, which in turn is determined by oceanographic features. Thus, the identification of the specific foraging behaviors associated with different environmental conditions is of primary relevance to understanding the foraging behavior of top predators. The southern elephant seal (Mirounga leonina) and crabeater seal (Lobodon carcinophaga) are important top predators of the Southern Ocean, and as such, they can integrate information about several layers of primary and secondary productivity. Moreover, these two species are part of different trophic pathways of the Southern Ocean. Elephant seals are part of the northern slope and oceanic waters food web, where copepods, mesopelagic fish and squid occupy the mid-trophic levels. Crabeater seals are part of the southern food web, where the Antarctic krill, Euphausia superba, is considered the dominant species in the seasonal pack ice zone.The main goal of my study was to determine what level of flexibility, if any, is displayed by the southern elephant seals and crabeater seals from the western Antarctic Peninsula (wAP) in their foraging behavior and habitat utilization patterns, using a combination of stable isotope data (δ13C and δ 15N ), satellite telemetry data (tracking and diving) and environmental data (from animal-borne sensors, oceanographic models and satellite oceanography) to address two main aspects of the ecology of the two species: (a) Feeding habits and trophic ecology, and (b) Habitat utilization in relation with the oceanography.Combining stable isotope analysis and satellite telemetry, I studied the variability in individual foraging strategies of adult female southern elephant seals analyses (Chapter 1). Most individuals were specialists, with half of the individuals utilizing 31% or less of their available niche. I found 8 different foraging strategies for these animals. Hence, female elephant seals from the wAP are a diverse group of predators with individuals utilizing only a small portion of the total available niche, and therefore have the potential to expand their range to exploit new niches that will potentially become available as a consequence of environmental change. Due to the high specialization of crabeater seal to forage on Antarctic krill Euphausia superba, the species is particularly vulnerable to the environmental changes that are already occurring in the Southern Ocean as a consequence of the climatic global change. Using stable isotopes, I studied the trophic ecology of crabeater seals from the western Antarctica Peninsula (Chapter 2). The median (range) contribution of Antarctic krill to the diet of the crabeater seal from the western Antarctica Peninsula (wAP) is 87.9 (81.2 - 94.8) %, however the results showed that crabeater seals are capable of displaying trophic plasticity, supplementing their diet with other prey that might be available in the environment (i.e. fish). I also investigated the foraging behavior of adult female elephant seals from the wAP in relation with the in situ oceanographic conditions that they experience during their ca. 8-months post-molt migration at sea (Chapter 3). There was a wide diversity in the areas utilized by elephant seals contradicting the general idea of elephant seals as being part of the northern slope and oceanic waters food web of the Southern Ocean, where copepods, mesopelagic fish and squid occupy the mid-trophic levels, and extends their range into the southern/coastal food web, where the Antarctic krill, Euphausia superba, is considered the dominant mid-trophic species. Finally I present a suit of habitat models for a conspicuous predator of the wAP: the crabeater seal, likely the largest consumer of krill in the world (Chapter 4). Crabeater seals from the wAP presented a coastal distribution, occupying water of the inner continental shelf preferably, and rarely venturing beyond the break of the continental shelf (1,000 isobath). The best habitat model, included variables associated with bathymetry and water column features. Crabeater seals preferred shelf areas between 100 and 200 km from the shelf break, with bathymetric slope of about 5° (~10%), and shallow depths (<500 m deep). As well I found a negative trend between crabeater seals and zones of intrusions of warm, off-shelf Circumpolar Deep Water (CDW)