Dispersal of southern elephant seals (Mirounga leonina) from Davis Base, Antarctica: Combining population genetics and tracking data

Marine animals such as the southern elephant seal (Mirounga leonina) rely on a productive marine environment and are vulnerable to oceanic changes that can affect their reproduction and survival rates. Davis Base, Antarctica, acts as a moulting site for southern elephant seals that forage in Prydz Bay, but the genetic diversity and natal source populations of these seals has not been characterized. Determining the genetic diversity of moulting populations like this one provides essential information on seal dispersal, inter-population mixing, and foraging behaviours. In this study, we combined genetic and animal tracking data on these moulting seals to identify levels of genetic diversity, natal source population, and movement behaviours during foraging and haul-out periods. Using mitochondrial sequence data, we identified two major breeding lineages of seals at Davis Base. We found that the majority of the seals originated from breeding stocks within the South Atlantic Ocean and South Indian Ocean. One seal was grouped with the Macquarie Island breeding stock (South Pacific Ocean). The Macquarie Island population, unlike the other two stocks, is decreasing in size. Tracking data revealed long-distance foraging activity of the Macquarie Island seal around Crozet Islands. We speculate that changes to the Antarctic marine environment have resulted in a shift in foraging and dispersal strategies, which subsequently affects seal population growth rates. These findings have implications for conservation management plans aimed at improving the population status of the southern elephant seal.

Determinants of moult haulout phenology and duration in southern elephant seals

Phenological shifts are among the most obvious biological responses to environmental change, yet documented responses for Southern Ocean marine mammals are extremely rare. Marine mammals can respond to environmental changes through phenological flexibility of their life-history events such as breeding and moulting. Southern elephant seals (Mirounga leonina) undergo an obligatory annual moult which involves the rapid shedding of epidermal skin and hair while seals fast ashore. We quantified the timing (phenology) and duration (the time from arrival ashore to departure) of the moult haulout of 4612 female elephant seals at Marion Island over 32 years. Using linear mixed-effects models, we investigated age, breeding state and environmental drivers of moult timing and haulout duration. We found no clear evidence for a temporal shift in moult phenology or its duration. Annual variation in moult arrival date and haulout duration was small relative to age and breeding effects, which explained more than 90% of the variance in moult arrival date and 25% in moult haulout duration. All environmental covariates we tested explained minimal variation in the data. Female elephant seals moulted progressively later as juveniles, but adults age 4 and older had similar moult start dates that depended on the breeding state of the female. In contrast, moult haulout duration was not constant with age among adults, but instead became shorter with increasing age. Moulting is energetically expensive and differences in the moult haulout duration are possibly due to individual variation in body mass and associated metabolizable energy reserves, although other drivers (e.g. hormones) may also be present. Individual-based data on moult arrival dates and haulout duration can be used as auxiliary data in demographic modelling and may be useful proxies of other important biological parameters such as body condition and breeding history.

Observational/hydrographic data of the South Atlantic Ocean published as LOD

This article describes the publication of occurrences of Southern Elephant Seals Mirounga leonina (Linnaeus, 1758) as Linked Open Data in two environments (marine and coastal). The data constitutes hydrographic measurements of instrumented animals and observation data collected during censuses between 1990 and 2017. The data scheme is based on the previously developed ontology BiGe-Onto and the new version of the Semantic Sensor Network ontology (SSN). We introduce the network of ontologies used to organize the data and the transformation process to publish the dataset. In the use case, we develop an application to access and analyze the dataset. The linked open dataset and the related visualization tool turned data into a resource that can be located by the international community and thus increase the commitment to its sustainability. The data, coming from Península Valdés (UNESCO World Heritage), is available for interdisciplinary studies of management and conservation of marine and coastal protected areas which demand reliable and updated data.

Design of Deployment Strategies to Monitor the Movement of Animals with Passive Electronic Devices

Current animal monitoring systems have improved our knowledge of quantitative animal ecology. There are many electronic tracking technologies such as VHF/UHF telemetry, light-level geolocation, ARGOS satellite telemetry and GPS tracking. To reach the desired level of information retrieval requires the planning of adequate equipment effort and coverage, which depends on the properties of the system. We propose an equipment arrangement model consisting of a given number of receiver stations in a two-dimensional space in which the animals move according to a central place movement model. The objective is to characterize how the transmission of tracking data depends on the movement of the animals and the design of the equipment deployment: quantity and location of the receiver stations and their associated reception radius. We also implement the model using real trajectories of southern elephant seals and Australian sea lions publicly available online and tracked during the years 2010–2012. We characterize the data transmission based on different equipment configurations and we obtained analogous results to the theoretical model.

Mawson’s views on use of natural resources in the Antarctic and sub-Antarctic

Sir Douglas Mawson is a well-known Antarctic explorer and scientist. Early in his career, he recognised opportunities for commerce in Antarctic and sub-Antarctic regions. While at Cape Denison, Antarctica, in 1913 on the Australasian Antarctic Expedition (AAE), the Adelie Blizzard magazine was produced. Mawson contributed articles about Antarctic natural resources and their possible use. Later, he advocated Australia be involved in pelagic whaling. He collected seal skins and oil for their commercial value to be assessed by the Hudson’s Bay Company. During the AAE, Mawson visited Macquarie Island where an oiling gang was killing southern elephant seals and royal penguins. Mawson was concerned that they were over-exploited and lobbied successfully to stop the killing. His plans for Macquarie Island included a wildlife sanctuary, with a party to supervise access, send meteorological observations to Australia and New Zealand, and be self-funded by harvesting elephant seals and penguins. Macquarie Island was declared a sanctuary in 1933. Although Mawson has been recognised as an early proponent of conservation, his views on conservation of living natural resources were inconsistent. They should be placed in their historical context: in the early twentieth century, utilisation of living natural resources was viewed more favourably than currently.