Flash and grab : deep-diving southern elephant seals trigger anti-predator flashes in bioluminescent prey

Funding: Fondation BNP Paribas; Centre National d'Etudes Spatiales; Institut Polaire Français Paul Emile Victor; Natural Environment Research Council; H2020 Marie Skłodowska-Curie Actions.Bioluminescence, which occurs in approximately 80% of the world's mesopelagic fauna, can take the form of a low-intensity continuous glow (e.g. for counter-illumination or signalling) or fast repetitions of brighter anti-predatory flashes. The southern elephant seal (SES) is a major consumer of mesopelagic organisms, in particular the abundant myctophid fish, yet the fine-scale relationship between this predator's foraging behaviour and bioluminescent prey remains poorly understood. We hypothesised that brief, intense light emissions should be closely connected with prey strikes when the seal is targeting bioluminescent prey that reacts by emitting anti-predator flashes. To test this, we developed a biologging device containing a fast-sampling light sensor together with location and movement sensors to measure simultaneously anti-predator bioluminescent emissions and the predator's attack motions with a 20 ms resolution. Tags were deployed on female SES breeding at Kerguelen Islands and Península Valdés, Argentina. In situ light levels in combination with duration of prey capture attempts indicated that seals were targeting a variety of prey types. For some individuals, bioluminescent flashes occurred in a large proportion of prey strikes, with the timing of flashes closely connected with the predator's attack motion, suggestive of anti-predator emissions. Marked differences across individuals and location indicate that SES do exploit bioluminescent organisms but the proportion of these in the diet varies widely with location. The combination of wideband light and acceleration data provides new insight into where and when different prey types are encountered and how effectively they might be captured.Publisher PDFPeer reviewe

Trayectorias y bioregistro de elefantes marinos del sur (Mirounga leonina) de Península Valdés

Para comprender la relación entre la elección de las áreas de alimentación de los elefantes marinos del sur (Mirounga leonina) y las características oceanográficas allí presentes (ej. sistemas frontales y eddies), se requiere obtener datos a pequeña escala tanto de las trayectorias realizadas por los animales durante la etapa pelágica en el mar, como del ambiente marino que utilizan. Para ello se emplean dispositivos satelitales que registran la información oceanográfica a medida que el animal viaja en el mar. En enero de 2016 se instrumentaron tres hembras adultas de la colonia de Península Valdés (PV) con dispositivos CTD-SRDL. Estos instrumentos registran la temperatura, profundidad y conductividad del agua, cada 4 segundos, a profundidades de más de mil metros y con una autonomía de 8-9 meses sin interrupción. De esta manera, los elefantes marinos se comportan como verdaderas plataformas oceanográficas ya que permiten caracterizar el ambiente físico con un nivel de precisión no registrado anteriormente. Los resultados preliminares indican que los animales seleccionaron distintos ambientes oceánicos. Una de las hembras recorrió más de 2300 km en línea recta desde PV llegando hasta las Islas Georgias del Sur. Otra, eligió la rama Norte de la Corriente Circumpolar Antártica para viajar hacia el Este, siguiendo el Frente Subantártico y recorriendo más de 3300 km. Otra elección fue la ruta hacia el Noreste siguiendo el talud, copiando el eje de la Corriente de Malvinas. Viajó aproximadamente más de 1600 km y permaneció más de tres meses al Norte de la máxima extensión hacia el Norte de dicha corriente. En general todas invirtieron el 90% del tiempo buceando, alcanzando profundidades entre los 1000-1083 m. La información de las distancias, profundidades y áreas elegidas, permitirán identificar hábitats clave no sólo para la especie estudiada sino también para el resto de los depredadores mesopelágicos del Atlántico Sudoccidental.Fil: Campagna, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Lewis, Mirtha Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina6ta Jornada de Presentación de BecariosPuerto MadrynArgentinaCentro Nacional Patagónic

Catastrophic mortality of southern elephant seals caused by H5N1 avian influenza

We report on the first outbreak of high pathogenicity H5N1 avian influenza, causing extreme mortality in the southern elephant seal, Mirounga leonina, at Península Valdés (PV) and nearby areas, in Argentina. The virus was con-firmed by the Argentine Government Animal Health Service (SENASA) on samples collected from elephant seals at PV. Findings were reported by the national authorities to the World Organisation for Animal Health and are available through the World Animal Health Information System under event ID 5189 (specifically, outbreaks OB_126883 and OB_124986).Fil: Campagna, Claudio. Wildlife Conservation Society; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Uhart, Marcela María. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentina. University of California at Davis; Estados UnidosFil: Falabella, Valeria. Wildlife Conservation Society; Estados UnidosFil: Campagna, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Wildlife Conservation Society; Estados UnidosFil: Zavattieri, Victoria. Wildlife Conservation Society; Estados UnidosFil: Vanstreels, Ralph E. T.. University Of California At Davis. School Of Veterinary Medicine; Estados UnidosFil: Lewis, Mirtha Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentin

Swimming in an ocean of curves: A functional approach to understanding elephant seal habitat use in the Argentine Basin

International audienceIn recent decades, southern elephant seals (SES) have become a species of particular importance in ocean data acquisition. The scientific community has taken advantage of technological advances coupled with suitable SES biological traits to record numerous variables in challenging environments and to study interactions between SES and oceanographic features. In the context of big dataset acquisition, there is a growing need for methodological tools to analyze and extract key data features while integrating their complexity. Although much attention has been paid to study elephant seal foraging strategies, the continuity of their surrounding three-dimensional environments is seldom integrated. Knowledge gaps persist in understanding habitat use by SES, while the representativeness of a predator-based approach to understanding ecosystem structuring is still questioned. In this study, we explore SES habitat use by using a functional data analysis approach (FDA) to describe the foraging environment of five female elephant seals feeding in the Southwestern Atlantic Ocean. Functional principal component analysis followed by model-based clustering were applied to temperature and salinity (TS) profiles from Mercator model outputs to discriminate waters sharing similar thermohaline structures. Secondly, in situ TS profiles recorded by the SES were employed to determine the habitat visited within the range of potential environments identified from the model data. Four Functional Oceanographic Domains (FOD) were identified in the Brazil-Malvinas Confluence, all visited, in varying proportion, by four of the five females studied. We found that the females favored areas where all the FODs converge and mix, generating thermal fronts and eddies. Prey-capture attempts increased in such areas. Our results are in accordance with previous findings, suggesting that (sub-)mesoscale features act as biological hotspots. This study highlights the potential of coupling FDA with model-based clustering for describing complex environments with minimal loss of information. As well as contributing to better understanding of elephant seal habitat use and foraging strategies, this approach opens up a wide range of applications in oceanography and ecology

Physical changes recorded by a deep diving seal on the Patagonian slope drive large ecological changes

The Patagonian slope is the region where Subantarctic waters and bathymetry give raise to physical and ecological processes that support a rich biodiversity and a large-scale industrial fisheries. Unique among the species that depend on this region is the deep diving southern elephant seal, Mirounga leonina. We report here on changes in the foraging behavior of a female seal explained by the combined effect of a cold and high salinity water mass and a decrease in surface chlorophyll-a concentration. Behavioral and oceanographic data from about 5000 profiles of temperature, conductivity, pressure, light and prey encounters were collected within an area ranging 59.5–61°W and 46–47.5°S, at depths of 300–700 m, on the Patagonian slope, during November–December 2018. A decrease in temperature (0.15 °C) and an increase in salinity (0.03) was found below the mixed layer, during December. Light data revealed a significant increase of irradiance in December (almost reaching the ocean bottom) associated with a decrease of chlorophyll-a in the upper levels. Concomitantly, the seal had a different diving behavior in December, foraging near the surface at night and close to the bottom during daylight hours. Also, the seal doubled the prey capture attempts in December compared to November. This study reveals the importance of ocean physical properties on seal's diving and foraging behavior, and how this changes, although small, can impact on seals diet and body composition during their post-breeding trips.Fil: Aubone Videla, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; ArgentinaFil: Saraceno, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Instituto Franco-Argentino sobre Estudios del Clima y sus Impactos; ArgentinaFil: Torres Alberto, María Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Campagna, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Ster, L. Le. La Rochelle Université; Francia. Centre National de la Recherche Scientifique. Observatoire Océanologique de Villefranche Sur Mer; FranciaFil: Picard, B.. La Rochelle Université; FranciaFil: Hindell, M.. University of Tasmania; AustraliaFil: Campagna, Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina. Wildlife Conservation Society; Estados UnidosFil: Guinet, C. R.. La Rochelle Université; Franci

Ontogenetic niche partitioning in southern elephant seals from Argentine Patagonia

Elephant seals, Mirounga spp., are highly dimorphic, having different energetic requirements according to age and sex, and foraging in various ecological and oceanographic contexts. Resource partitioning has been shown for the sub-Antarctic populations of southern elephant seals, M. leonina, where colonies are surrounded by narrow shelves that deepen abruptly. In contrast, seals from Península Valdés (Argentina), in the northernmost extent of the breeding range, face an extended, shallow, temperate, and productive continental shelf. We integrated tracking data from 98 animals (juveniles and adults, males and females) gathered over more than two decades, and found that although all available habitats were used, individuals segregated by age and sex. Juvenile males favored shelf habitats, whereas subadult and adult males also used the shelf break. Juvenile females preferred the shelf and the more distant Argentine Basin used by postbreeding and postmolt adult females. Males showed the highest proportion of area-restricted search locations, suggesting more spatially concentrated feeding activity, and likely reflecting a preference for foraging habitat and prey. Our results are consistent with those from other populations, implying that elephant seals show remarkable similarities in habitat use by age and sex classes, despite broad differences in the offshore habitats between sub-Antarctic and temperate ecosystems.Fil: Campagna, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Lewis, Mirtha Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: González Carman, Victoria. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Campagna, Claudio. Wildlife Conservation Society, Marine and Argentina Programs; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Guinet, Christophe. Université de La Rochelle; FranciaFil: Johnson, Mark. University of St. Andrews; Reino Unido. University Aarhus; DinamarcaFil: Davis, Randall W.. Texas A&M University; Estados UnidosFil: Rodríguez, Diego Hernán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Hindell, Mark A.. University of Tasmania; Australi

Physiological and behavioural responses of bottlenose dolphin Tursiops truncatus to gustatory, olfactory and trigeminal chemical stimuli

Mare CampInternational audienceChemical perception is the first modality that evolved in animals to sense the surrounding world. In terrestrials’ mammals, chemical perception plays a crucial role in feeding, orientation, communication and much more. Conversely, information regarding this aspect is notably scarce in marine mammals, especially in cetaceans. The limited studies available so far indicate a partial regression of both anatomical structures and key genes families involved in olfaction and gustation. However, different behavioural observations suggest that chemical perception could be functional. In this study, we aimed to shed light on the chemical perception of Bottlenose Dolphins, focusing one of the chemical facet : gustatory sense. Gustation is characterized by the detection of molecules through taste receptors on the surface of papillae. We expected to unveil conserved processes and signalling pathways, through physiological and behavioural measurements. These findings would indicate that chemical senses could have kept a biological utility through odontocetes evolution

Physiological and behavioural responses of bottlenose dolphin Tursiops truncatus to gustatory, olfactory and trigeminal chemical stimuli

Mare CampInternational audienceChemical perception is the first modality that evolved in animals to sense the surrounding world. In terrestrials’ mammals, chemical perception plays a crucial role in feeding, orientation, communication and much more. Conversely, information regarding this aspect is notably scarce in marine mammals, especially in cetaceans. The limited studies available so far indicate a partial regression of both anatomical structures and key genes families involved in olfaction and gustation. However, different behavioural observations suggest that chemical perception could be functional. In this study, we aimed to shed light on the chemical perception of Bottlenose Dolphins, focusing one of the chemical facet : gustatory sense. Gustation is characterized by the detection of molecules through taste receptors on the surface of papillae. We expected to unveil conserved processes and signalling pathways, through physiological and behavioural measurements. These findings would indicate that chemical senses could have kept a biological utility through odontocetes evolution

Satellite and High-Spatio-Temporal Resolution Data Collected by Southern Elephant Seals Allow an Unprecedented 3D View of the Argentine Continental Shelf

International audienceHigh spatial and temporal resolution hydrographic data collected by Southern Elephant Seals (Mirounga leonina, SESs) and satellite remote sensing data allow a detailed oceanographic description of the Argentine Continental Shelf (ACS). In-situ data were obtained from the CTD (Conductivity, Temperature, and Depth), accelerometer, and hydrophone sensors attached to five SESs that crossed the ACS between the 17th and 31st of October 2019. The analysis of the temperature (T) and salinity (S) along the trajectories allowed us to identify two different regions: north and south of 42°S. Satellite Sea Surface Temperature (SST) data suggests that north of 42°S, warm waters are coming from the San Matias Gulf (SMG). The high spatio-temporal resolution of the in-situ data shows regions with intense gradients along the T and S sections that were associated with a seasonal front that develops north of Península Valdés in winter due to the entrance of cold and fresh water to the SMG. The speed of the SESs is correlated with tidal currents in the coastal portion of the northern region, which is in good agreement with the macrotidal regime observed. A large number of Prey Catch Attempts (PCA), a measure obtained from the accelerometer sensor, indicates that SESs also feed in this region, contradicting suggestions from previous works. The analysis of wind intensity estimated from acoustic sensors allowed us to rule out the local wind as the cause of fast thermocline breakups observed along the SESs trajectories. Finally, we show that the maximum depth reached by the elephant seals can be used to detect errors in the bathymetry charts